The metadata of energy-related datasets from the following repositories is used in this multi-repository assessment of conformance of metadata with [OEMetadata v2](https://github.com/OpenEnergyPlatform/oemetadata): - Energy Data eXchange: https://edx.netl.doe.gov/ - EU Open Data Portal: https://data.europa.eu/data/datasets - Eurostat: https://ec.europa.eu/eurostat - FfE Open Data Portal: https://opendata.ffe.de/ - Inspire-HEP: https://inspirehep.net - Open Energy Data Initiative: https://data.openei.org/ - Open Energy Platform: https://openenergyplatform.org/database/ - OpenAIRE: https://explore.openaire.eu/ - Open Power System Data (OPSD): https://open-power-system-data.org/ - Open Access Power-Grid Frequency Database: https://osf.io/m43tg/ Unfortunately, we cannot share the scripts that we used for downloading the metadata from these repositories. However, we are sharing our preprocessing scripts for the repositories which needed preprocessing before mapping them to OEMetadata. These scripts would be executed directly after retrieving the metadata from the repository. In order to map the raw metadata (see `metadata_raw`) to the OEMetadata, execute ```bash pip install -r requirements.txt python parser.py ``` The transformed metadata is then stored in a directory called `metadata_mapped`. To fix some reporting issues with nested fields, execute the cleanup script for the OEP: ```bash python cleanup_oep.py ``` Now you are ready to reproduce our report by running ```bash python report.py ``` The reports for each of the repositories is then stored in the directory `report`.
All files required to reproduce the reported results, including raw metadata, mappings, and scripts
CERN-LHC. Multi-particle cumulants and corresponding Fourier harmonics are measured for azimuthal angle distributions of charged particles in pp collisions at $\sqrt{s}$ = 5.02 and 13 TeV and in p+Pb collisions at $\sqrt{s_{NN}}$ = 5.02 TeV, and compared to the results obtained for low-multiplicity Pb+Pb collisions at $\sqrt{s_{NN}}$ = 2.76 TeV. These measurements aim to assess the collective nature of particle production. The measurements of multi-particle cumulants confirm the evidence for collective phenomena in p+Pb and low-multiplicity Pb+Pb collisions. On the other hand, the pp results for four-particle cumulants do not demonstrate collective behaviour, indicating that they may be biased by contributions from non-flow correlations. A comparison of multi-particle cumulants and derived Fourier harmonics across different collision systems is presented as a function of the charged-particle multiplicity. For a given multiplicity, the measured Fourier harmonics are largest in Pb+Pb, smaller in p+Pb and smallest in pp collisions. The pp results show no dependence on the collision energy, nor on the multiplicity.
Measurement of multi-particle azimuthal correlations in $pp$, $p$+Pb and low-multiplicity Pb+Pb collisions with the ATLAS detector
CERN-LHC, ATLAS. Acceptance times efficiency Basic event selection: - Additional selection: Signal region (SR): - Control Region (CR): - Validation Region (VR): -
Searches for heavy $ZZ$ and $ZW$ resonances in the $\ell\ell qq$ and $\nu\nu qq$ final states in $pp$ collisions at $\sqrt{s}=13$ TeV with the ATLAS detector
A search for the decay of the Higgs boson to a Z boson and a light, pseudoscalar particle, a, decaying respectively to two leptons and to two photons is reported. The search uses the full LHC Run 2 proton-proton collision data at sqrt(s)=13 TeV, corresponding to 139 fb-1 collected by the ATLAS detector. This is one of the first searches for this specific decay mode of the Higgs boson, and it probes unexplored parameter space in models with axion-like particles (ALPs) and extended scalar sectors. The mass of the a particle is assumed to be in the range 0.1-33 GeV. The data are analysed in two categories: a merged category where the photons from the a decay are reconstructed in the ATLAS calorimeter as a single cluster, and a resolved category in which two separate photons are detected. The main background processes are from Standard Model Z boson production in association with photons or jets. The data are in agreement with the background predictions, and upper limits on the branching ratio of the Higgs boson decay to Za times the branching ratio a->yy are derived at the 95% confidence level and they range from 0.08% to 2% depending on the mass of the a particle. The results are also interpreted in the context of ALP models.
Search for the decay of the Higgs boson to a $Z$ boson and a light pseudoscalar particle decaying to two photons
A search for $B-L$ $R$-parity-violating top squarks in $\sqrt{s} = 13$ TeV $pp$ collisions with the ATLAS experiment
Search for $WW/WZ$ resonance production in $\ell \nu qq$ final states in $pp$ collisions at $\sqrt{s} =$ 13 TeV with the ATLAS detector
A search is conducted for a new scalar boson $S$, with a mass distinct from that of the Higgs boson, decaying promptly into four leptons ($\ell =$ $e$, $\mu$) via an intermediate state containing two on-shell, promptly decaying new spin-1 bosons $Z_{d}$: $S \rightarrow Z_{d}Z_{d} \rightarrow 4\ell$, where the $Z_{d}$ boson has a mass between 15 and 300 GeV, and the $S$ boson has a mass between either 30 and 115 GeV or 130 and 800 GeV. The search uses proton-proton collision data collected with the ATLAS detector at the Large Hadron Collider with an integrated luminosity of 139 fb$^{-1}$ at a centre-of-mass energy of $\sqrt{s}=13$ TeV. No significant excess above the Standard Model background expectation is observed. Upper limits at 95% confidence level are set on the production cross-section times branching ratio, $\sigma(gg \rightarrow S) \times \mathcal{B}(S\rightarrow Z_{d}Z_{d} \rightarrow 4\ell)$, as a function of the mass of both particles, $S$ and $m_{Z_{d}}$.
Search for a new scalar decaying into new spin-1 bosons in four-lepton final states with the ATLAS detector
Search for heavy resonances decaying to a $W$ or $Z$ boson and a Higgs boson in the $q\bar{q}^{(\prime)}b\bar{b}$ final state in $pp$ collisions at $\sqrt{s} = 13$ TeV with the ATLAS detector
CERN-LHC, ATLAS. Limits on the production of dark matter candidates in association with a SM Higgs boson decaying to a bottom-quark pair in two Higgs doublet models with a vector or pseudoscalar mediator.
Search for dark matter produced in association with a Standard Model Higgs boson decaying into $b$-quarks using the full Run 2 dataset from the ATLAS detector
CERN-LHC. The production rates of prompt and non-prompt $J/\psi$ and $\psi(2\mathrm{S})$ mesons are measured using 140 $fb^{-1}$ of data collected with the ATLAS experiment at the LHC, in proton-proton collisions at $\sqrt{s}=13$ TeV. Production cross-sections for both prompt and non-prompt production sources, ratios of $\psi(2\mathrm{S})$ to $J/\psi$ production, and fractions of non-prompt to inclusive production for $J/\psi$ and $\psi(2\mathrm{S})$ are measured double-differentially as a function of meson $p_{T}$ and rapidity.
Measurement of the production cross-section of $J/\psi$ and $\psi(2$S$)$ mesons in $pp$ collisions at $\sqrt{s} = 13$ TeV with the ATLAS detector
CERN-LHC. The production of $Z$ bosons with one or two isolated high-energy photons is studied using $pp$ collisions at $\sqrt{s}$ = 8 TeV. The analyses use a data sample with an integrated luminosity of 20.3 fb$^{-1}$ collected by the ATLAS detector during the 2012 LHC data taking. The $Z\gamma$ and $Z\gamma\gamma$ production cross sections are measured with leptonic ($e^{+}e^{-}$, $\mu^{+}\mu^{-}$, $\nu\bar{\nu}$) decays of the $Z$ boson, in extended fiducial regions defined in terms of the lepton and photon acceptance. They are then compared to cross-section predictions from the Standard Model, where the sources of the photons are radiation off initial-state quarks and radiative $Z$-boson decay to charged leptons, and from fragmentation of final-state quarks and gluons into photons. The yields of events with photon transverse energy $E_{\mathrm{T}} >$ 250 GeV from $\ell^{+}\ell^{-}\gamma$ events and with $E_{\mathrm{T}} >$ 400 GeV from $\nu\bar{\nu}\gamma$ events are used to search for anomalous triple gauge-boson couplings $ZZ\gamma$ and $Z\gamma\gamma$. The yields of events with diphoton invariant mass $m_{\gamma\gamma} >$ 200 GeV from $\ell^{+}\ell^{-}\gamma\gamma$ events and with $m_{\gamma\gamma} > $ 300 GeV from $\nu\bar{\nu}\gamma\gamma$ events are used to search for anomalous quartic gauge-boson couplings $ZZ\gamma\gamma$ and $Z\gamma\gamma\gamma$. No deviations from Standard Model predictions are observed and limits are placed on parameters used to describe anomalous triple and quartic gauge-boson couplings.
Measurements of $Z\gamma$ and $Z\gamma\gamma$ production in $pp$ collisions at $\sqrt{s}=$ 8 TeV with the ATLAS detector
Search for pair-produced scalar and vector leptoquarks decaying into third-generation quarks and first- or second-generation leptons in pp collisions with the ATLAS detector
CERN-LHC. The production of $D^{*\pm}$, $D^\pm$ and $D_s^\pm$ charmed mesons has been measured with the ATLAS detector in $pp$ collisions at $\sqrt{s}=7$ TeV at the LHC, using data corresponding to an integrated luminosity of $280\,$nb$^{-1}$. The charmed mesons have been reconstructed in the range of transverse momentum $3.5<p_{\rm T}(D)<100$ GeV and pseudorapidity $|\eta(D)|<2.1$. The differential cross sections as a function of transverse momentum and pseudorapidity were measured for $D^{*\pm}$ and $D^\pm$ production. The next-to-leading-order QCD predictions are consistent with the data in the visible kinematic region within the large theoretical uncertainties. Using the visible $D$ cross sections and an extrapolation to the full kinematic phase space, the strangeness-suppression factor in charm fragmentation, the fraction of charged non-strange $D$ mesons produced in a vector state, and the total cross section of charm production at $\sqrt{s}=7$ TeV were derived.
Measurement of $D^{*\pm}$, $D^\pm$ and $D_s^\pm$ meson production cross sections in $pp$ collisions at $\sqrt{s}=7$ TeV with the ATLAS detector
CERN-LHC. Measurement of the inelastic proton-proton cross section at a centre-of-mass energy of 13 TeV. The data set has a total integrated luminosity of 60 $\mu$b$^{-1}$. Scintillation counters in the forward region were used to select inelastic events. Results are given for a cut off of $M(X)^{2}/S > 1*10^{-6}$, equivalent to $M_X > 13$ GeV at 13 TeV and also extrapolated to the full range $M(P)^{2}/S$.
Measurement of the Inelastic Proton-Proton Cross Section at $\sqrt{s} = 13$ TeV with the ATLAS Detector at the LHC
CERN-LHC. Event-shape observables measured using charged particles in inclusive Z-Boson events are presented, using the electron and muon decay modes of the Z-bosons. The measurements are based on an integrated luminosity of $ 1.1 {\rm fb}^{-1}$ of proton--proton collisions recorded by the ATLAS detector at the LHC at a centre-of-mass energy $\sqrt{s}=7$ TeV. Charged-particle distributions, excluding the lepton--antilepton pair from the Z-boson decay, are measured in different ranges of transverse momentum of the Z-boson. Distributions include multiplicity, scalar sum of transverse momenta, beam thrust, transverse thrust, spherocity, and $\mathcal{F}$ -parameter, which are in particular sensitive to properties of the underlying event at small values of the Z-boson transverse momentum.
Measurement of event-shape observables in $Z \to \ell^{+} \ell^{-}$ events in $pp$ collisions at $\sqrt{s}=7$ TeV with the ATLAS detector at the LHC
CERN-LHC. Measurements on the triboson W+-W+-W-+ production cross-section using two decay channels fully-leptonic W+-W+-W-+ -> l+-nu l+-nu l-+nu and semi-leptonic W+-W+-W-+ -> l+-nu l+-nu jj (with l=e,mu) in proton-proton collision data corresponding to an integrated luminosity of 20.3 fb-1 at a centre of-mass energy of 8 TeV with the ATLAS detector at the Large Hadron Collider. Limits are also sets on WWWW anomalous quartic gauge couplings. The fully-leptonic channel (W+-W+-W-+ -> l+-nu l+-nu l-+nu ) is defined as (the exact definition is given in table 1 of the preprint): - Exactly 3 leptons electrons or muons with pT(Lepton)>25 GeV and |eta(Leptons)|<=2.5 - If there are 2 Same Flavor Opposite Signe (SFOS) pairs, MET>55 GeV, if there is 1 SFOS, MET>45 GeV, and if there is 0 SFOS pairs no requirement is applied on the MET. - If there is no SFOS pairs the invariant mass between any lepton paires mll > 20 GeV. No such requirements is applied in the presence of 1 or 2 SFOS pairs. - The angle between the trilepton system and the pTMiss must be |phi_3l-phi_met|>2.5 - If there is no SFOS pairs, |mee-mZ|>15 GeV, if there is one SFOS pair mZ-mSFOS>35 Gev or mSFOS-mZ>20 GeV, and if there are two SFOS pairs mSFOS-mZ|>20 GeV. - There should be at most 1 jet with pT>25 GeV and |eta|<4.5 - DeltaR(l,l)>0.1 The semi-leptonic channel (W+-W+-W-+ -> l+-nu l+-nu jj) is defined as (the exact definition is given in table 2 of the preprint): - Exactly 2 same-charge leptons electrons or muons with pT(Lepton)>30 GeV and |eta(Leptons)|<=2.5 - Veto the presence of any third lepton with pT>6 GeV and |\eta|<2.5 GeV. - In the ee final state mee<80 GeV or mee>100 GeV. - The lepton pair should satisfy mll>40 GeV. - There should be at least 2 jets with pT(j1)>30 GeV , pT(j2)>30 GeV and |eta|<2.5 - The dijet system should satisfy 65 GeV<mjj< 105 GeV and |Delta_Eta(jj)|<1.5 - If there is at least one electron in the events, MET>55 GeV. - DeltaR(l,l)>0.1 and DeltaR(l,j)>0.3
Search for triboson $W^{\pm}W^{\pm}W^{\mp}$ production in $pp$ collisions at $\sqrt{s}=8$ TeV with the ATLAS detector
CERN-ATLAS. Search for heavy resonances decaying into a W or Z boson and a Higgs boson in final states with leptons and b-jets in 36 1/fb of 13 TeV pp collisions with the ATLAS detector
Search for heavy resonances decaying into a $W$ or $Z$ boson and a Higgs boson in final states with leptons and $b$-jets in 36 fb$^{-1}$ of $\sqrt s = 13$ TeV $pp$ collisions with the ATLAS detector
CERN-LHC. Measurement of the cross-section for electroweak production of dijets in association with a Z boson in pp collisions at a centre-of-mass energy of 13 TeV with the ATLAS detector. The measurement was made using the 3.2 fb^-1 of data collected in 2015.
Measurement of the cross-section for electroweak production of dijets in association with a $Z$ boson in $pp$ collisions at $\sqrt{s}=13$ TeV with the ATLAS detector
A search is performed for new phenomena in events with a high-transverse momentum photon and jets collected in 36.7/fb of pp collisions at a centre-of-mass energy of 13 TeV recorded with the ATLAS detector at the Large Hadron Collider. The invariant mass distribution of the leading photon and jet is examined to look for a resonant production of new particles or the presence of new high-mass states beyond the Standard Model. No significant deviation is observed in the mass distribution from the background-only hypothesis and cross section limits for generic Gaussian-shaped resonances are extracted. Excited quarks hypothesized in the quark compositeness model and high-mass states predicted in the quantum black hole models with extra dimensions are also examined in the analysis. The observed data exclude, at 95% confidence level, mass range below 5.3 TeV for the excited quarks and 7.1 TeV (4.4 TeV) for the quantum black holes with six (one) extra dimensions in the Arkani-Hamed-Dimopoulos-Dvali (Randall-Sundrum) model.
Search for new phenomena in high-mass final states with a photon and a jet from $pp$ collisions at $\sqrt{s}$ = 13 TeV with the ATLAS detector
- CERN-LHC. Detailed measurements of $t$-channel single top-quark production are presented. They use $20.2~\mathrm{fb}^{-1}$ of data collected by the ATLAS experiment in proton--proton collisions at a centre-of-mass energy of 8 TeV at the LHC. Total, fiducial and differential cross-sections are measured for both top-quark and top-antiquark production. The fiducial cross-section is measured with a precision of $5.8~\%$ (top quark) and $7.8~\%$ (top antiquark), respectively. The total cross-sections are measured to be $\sigma_\mathrm{tot}(tq) = 56.7^{+4.3}_{-3.8}\;\mathrm{pb}$ for top-quark production and $\sigma_\mathrm{tot}(\bar{t} q) = 32.9^{+3.0}_{-2.7}\;\mathrm{pb}$ for top-antiquark production, in agreement with the Standard Model prediction. In addition, the ratio of top-quark to top-antiquark production cross-sections is determined to be $R_t=1.72 \pm 0.09$. The differential cross-sections as a function of the transverse momentum and rapidity of both the top quark and the top antiquark are measured at both the parton and particle levels. The transverse momentum and rapidity differential cross-sections of the accompanying jet from the $t$-channel scattering are measured at particle level. All measurements are compared to various Monte Carlo predictions as well as to fixed-order QCD calculations where available.
Fiducial, total and differential cross-section measurements of $t$-channel single top-quark production in $pp$ collisions at 8 TeV using data collected by the ATLAS detector
A search for nonresonant Higgs boson pair production in the $b\bar{b}\gamma\gamma$ final state is performed using 140 fb$^{-1}$ of proton--proton collisions at a centre-of-mass energy of 13 TeV recorded by the ATLAS detector at the CERN Large Hadron Collider. This analysis supersedes and expands upon the previous nonresonant ATLAS results in this final state based on the same data sample. The analysis strategy is optimised to probe anomalous values not only of the Higgs ($H$) boson self-coupling modifier $\kappa_\lambda$ but also of the quartic $HHVV$ ($V=W,Z$) coupling modifier $\kappa_{2V}$. No significant excess above the expected background from Standard Model processes is observed. An observed upper limit $\mu_{HH}<4.0$ is set at 95% confidence level on the Higgs boson pair production cross-section normalised to its Standard Model prediction. The 95% confidence intervals for the coupling modifiers are $-1.4<\kappa_\lambda<6.9$ and $-0.5<\kappa_{2V}<2.7$, assuming all other Higgs boson couplings except the one under study are fixed to the Standard Model predictions. The results are interpreted in the Standard Model effective field theory and Higgs effective field theory frameworks in terms of constraints on the couplings of anomalous Higgs boson (self-)interactions
Studies of new Higgs boson interactions through nonresonant $HH$ production in the $b\bar{b}\gamma\gamma$ final state in $pp$ collisions at $\sqrt{s}=13$ TeV with the ATLAS detector
CERN-LHC. High-precision measurements by the ATLAS Collaboration are presented of inclusive $W^+\to\ell^+\nu$, $W^-\to\ell^-\bar{\nu}$ and $Z/\gamma^*\to\ell\ell$ ($\ell=e,\mu$) Drell--Yan production cross sections at the LHC. The data were collected in proton--proton collisions at $\sqrt{s} = 7$ TeV with an integrated luminosity of 4.6 fb$^{-1}$. Differential $W^+$ and $W^-$ cross sections are measured in a lepton pseudorapidity range $|\eta_{\ell}| = 2.5$. Differential $Z/\gamma^*$ cross sections are measured as a function of the absolute dilepton rapidity, for $|y_{\ell\ell}| < 3.6$, for three intervals of dilepton mass, $m_{\ell\ell}$, extending from 46 to 150 GeV. The integrated and differential electron- and muon-channel cross sections are combined and compared to theoretical predictions using recent sets of parton distribution functions. The data, together with the final inclusive $e^{\pm}p$ scattering cross-section data from H1 and ZEUS, are interpreted in a next-to-next-to-leading-order QCD analysis, and a new set of parton distribution functions, ATLAS-epWZ16, is obtained. The ratio of strange-to-light sea-quark densities in the proton is determined more accurately than in previous determinations based on collider data only, and is established to be close to unity in the sensitivity range of the data. A new measurement of the CKM matrix element $|V_{cs}|$ is also provided. The differential cross sections are provided in two forms, a version with summarised uncertainties as in the paper tables and as "attached resource" files in HerAverager/xFitter format detailing all sources of correlated uncertainties separately. In addition to the experimental results, detailed information on the theoretical predictions are provided as required to reproduce the interpretation.
Precision measurement and interpretation of inclusive $W^+$, $W^-$ and $Z/\gamma^*$ production cross sections with the ATLAS detector
Particle level differential cross-section measurements for top-pair production, in event with at least an hadronically decaying top-quark, as a function of substructure of the boosted top-quark. Only charged particles are used to build the substructure. Two topologies, $l$+jets and all-hadronic, are considered. The study was performed using data from pp collisions at centre-of-mass energy of 13 TeV collected in Run2 by the ATLAS detector at the CERN Large Hadron Collider (LHC), corresponding to an integrated luminosity of 140 fb$^{−1}$. Due to the large cross-section at the LHC, such measurements allow a detailed study of the properties top-quark substructure, enabling precision tests of several Monte Carlo generators. The Monte Carlo predictions for measures of the broadness, and also the two-body structure, of the top-quark jets are found to be in good agreement with the measurements, while variables sensitive to the three-body structure of the top-quark jets exhibit some tension with the measured distributions .
Measurement of jet substructure in boosted $t\bar{t}$ events with the ATLAS detector using 140 fb$^{-1}$ of 13 TeV $pp$ collisions
CERN-LHC. Observables sensitive to the anomalous production of events containing hadronic jets and missing momentum in the plane transverse to the proton beams at the Large Hadron Collider are presented. The observables are defined as a ratio of cross sections, for events containing jets and large missing transverse momentum to events containing jets and a pair of charged leptons from the decay of a $Z/\gamma^\ast$ boson. This definition minimises experimental and theoretical systematic uncertainties in the measurements. This ratio is measured differentially with respect to a number of kinematic properties of the hadronic system in two phase-space regions; one inclusive single-jet region and one region sensitive to vector-boson-fusion topologies. The data are found to be in agreement with the Standard Model predictions and used to constrain a variety of theoretical models for dark-matter production, including simplified models, effective field theory models, and invisible decays of the Higgs boson. The measurements use 3.2 fb${}^{-1}$ of proton-proton collision data recorded by the ATLAS experiment at a centre-of-mass energy of 13 TeV and are fully corrected for detector effects, meaning that the data can be used to constrain new-physics models beyond those shown in this paper. Numerator and denominator ($\geq 1$ jet): - $p_\text{T}^\text{miss} > 200$ GeV - no additional electron or muon with $p_\text{T}$(lepton)>7 GeV and |$\eta$(lepton)|<2.5 - |$y$(jet)|<4.5 and $p_\text{T}$(jet)>25 GeV - $\Delta\phi$(jet,$p_\text{T}^\text{miss}$) > 0.4 for the four leading jets with $p_\text{T}$(jet)>30 GeV - leading $p_\text{T}$(jet)>120 GeV and |$\eta$(jet)|<2.4 Numerator and denominator (VBF): - $p_\text{T}^\text{miss} > 200$ GeV - no additional electron or muon with $p_\text{T}$(lepton)>7 GeV and |$\eta$(lepton)|<2.5 - |$y$(jet)|<4.5 and $p_\text{T}$(jet)>25 GeV - $\Delta\phi$(jet,$p_\text{T}^\text{miss}$) > 0.4 for the four leading jets with $p_\text{T}$(jet)>30 GeV - leading pT(jet)>80 GeV and subleading pT(jet)>50 GeV - $m_\text{jj}$>200 GeV - no additional jets with $p_\text{T}$(jet)>25 GeV inside rapidity interval Denominator only ($\geq 1$ jet and VBF): - leading $p_\text{T}$(lepton)>80 GeV and |$\eta$(lepton)|<2.5 - subleading $p_\text{T}$(lepton)>7 GeV and |$\eta$(lepton)|<2.5 - 66 GeV $< m_{\ell\ell}<$ 116 GeV - $\Delta R$(jet,lepton)>0.5, otherwise jet is removed
Measurement of detector-corrected observables sensitive to the anomalous production of events with jets and large missing transverse momentum in $pp$ collisions at $\sqrt{s} = 13$ TeV using the ATLAS detector
CERN-LHC. Measurements of the cross-section of the electroweak production in Zy final state in association with two jets, using two decay channels Z -> l+ l- and Z -> nu nu~ (with l=e,mu and nu=e/mu/tau neutrinos and nu~=e/mu/tau anti-neutrinos and y=photons) in proton-proton collision data corresponding to an integrated luminosity of 20.2 fb-1 at a centre of-mass energy of 8 TeV with the ATLAS detector at the Large Hadron Collider. Limits are also sets on WWZy/ZZZy/ZyZy/yyZy anomalous quartic gauge couplings. The charged-leptonic channel Zyjj electroweak process cross sections are measured in two regions, one of which is constructed with maximized sensitivity to Zyjj electroweak process (SR) and the other region is defined as the Zyjj QCD process control region (CR). A further optimized region with higher Et photon cut applied is used to probe the anomalous quartic couplings (aQGC). The neutrino channel is probed in a region used to further improve the sensitivity to aQGC and combined with charged leptonic channel. The detailed definitions are summarized as follows. The charged-leptonic channel (Z -> l+ l- ) is defined as (the exact definition is given in table 5 of the preprint): - 2 Same Flavor Opposite Sign (SFOS) leptons (electrons or muons) with pT(Lepton)>25 GeV and |eta(Lepton)|<=2.5 - 1 isolated photon with ET(Photon)>15 GeV and |eta(Photon)|<=2.37 - 2 jets with pT(Jet)>30 GeV and |eta(Jet)|<4.5 - |m(LeptonLepton) + m(LeptonLeptonPhoton)| > 182 GeV, |m(LeptonLepton)|>40 GeV - DeltaR(Lepton, Photon)>0.4, DeltaR(Jet, Photon)>0.4, DeltaR(Jet, Lepton)>0.3 - SR is defined with |m(JetJet)|>500 GeV - CR is defined with 500 GeV>|m(JetJet)|>150 GeV - aQGC search region is defined on top of SR with ET(Photon)>250 GeV - Requirement of Photon isolation (particle level only): ET(isolation)/ET(Photon) < 0.5. The photon isolation energy is taken as the energy of the jet matching the photon (DeltaR(Jet, Photon)<0.3), with the photon energy subtracted. The neutrino channel (Z -> nu nu~) is defined as (the exact definition is given in table 8 of the preprint): - two-neutrino-system pT>100 GeV - 1 isolated photon with ET(Photon)>150 GeV and |eta(Photon)|<=2.37 - 2 jets with pT(Jet)>30 GeV and |eta(Jet)|<4.5 - |m(LeptonLepton) + m(LeptonLeptonPhoton)| > 182 GeV, |m(LeptonLepton)|>40 GeV - DeltaR(Jet, Photon)>0.4 - |m(JetJet)|>600 GeV - Rapidity gap between two jets greater than 2.5 - photon centrality less than 0.3 and event pT balance less than 0.1 (variable definitions can be found in equation 1 and 2 of the preprint) - DeltaR(ET(NeutrinoNeutrino), JetJetPhoton)>3*PI/4., DeltaR(ET(NeutrinoNeutrino), JetJetPhoton)>PI/2., DeltaR(ET(NeutrinoNeutrino), Jet)>1. - Requirement of Photon isolation (particle level only): ET(isolation)/ET(Photon) < 0.5. The photon isolation energy is taken as the energy of the jet matching the photon (DeltaR(Jet, Photon)<0.3), with the photon energy subtracted.
Studies of $Z\gamma$ production in association with a high-mass dijet system in $pp$ collisions at $\sqrt{s}$ = 8 TeV with the ATLAS detector
Statistical combinations of searches for charginos and neutralinos using various decay channels are performed using $139\,$fb$^{-1}$ of pp collision data at $\sqrt{s}$=13 TeV with the ATLAS detector at the Large Hadron Collider. Searches targeting pure-wino chargino pair production, pure-wino chargino-neutralino production, or higgsino production decaying via Standard Model W, Z, or h bosons are combined to extend the mass reach to the produced SUSY particles by 30-100 GeV. The depth of the sensitivity of the original searches is also improved by the combinations, lowering the 95% CL cross-section upper limits by 15%-40%.
A statistical combination of ATLAS Run 2 searches for charginos and neutralinos at the LHC
Combination and summary of ATLAS dark matter searches interpreted in a 2HDM with a pseudo-scalar mediator using 139 fb$^{-1}$ of $\sqrt{s} = 13$ TeV $pp$ collision data
Measurement of forward-backward multiplicity correlations in lead-lead, proton-lead, and proton-proton collisions with the ATLAS detector
CERN-LHC, ATLAS. Measurements of the fiducial and total cross sections for Z production using the electron and muon final states in proton-proton collisions at a centre-of-mass energy of 13 TeV with 3.2 fb^-1 of data collected in 2015. Measurements of single and double fiducial and total cross-section ratios for ttbar and Z production at 13, 8, and 7TeV.
Measurements of top-quark pair to $Z$-boson cross-section ratios at $\sqrt s = 13, 8, 7$TeV with the ATLAS detector
This paper presents a search for a new $Z^\prime$ resonance decaying into a pair of dark quarks which hadronise into dark hadrons before promptly decaying back to Standard Model particles. This analysis is based on proton-proton collision data recorded at $\sqrt{s}=13$ TeV with the ATLAS detector at the Large Hadron Collider between 2015 and 2018, corresponding to an integrated luminosity of 139 fb$^{-1}$. After selecting events containing large-radius jets with high track multiplicity, the invariant mass distribution of the two leading jets is scanned to look for an excess above a data-driven estimate of the Standard Model multi-jet background. No significant excess of events is observed and the results are thus used to set $95 \%$ confidence-level upper limits on the production cross-section times branching ratio of the $Z^\prime$ to dark quarks as a function of the $Z^\prime$ mass for various dark-quark scenarios.
Search for Resonant Production of Dark Quarks in the Dijet Final State with the ATLAS Detector
Numbers taken from table 1 of arXiv:1605.03513v1.
Measurement of the forward-backward asymmetries in the production of $\Xi$ and $\Omega$ baryons in $p \bar{p}$ collisions
This paper presents the measurement of fiducial and differential cross sections for both the inclusive and electroweak production of a same-sign $W$-boson pair in association with two jets ($W^\pm W^\pm jj$) using $139\,\mathrm{fb}^{-1}$ of proton--proton collision data recorded at a centre-of-mass energy of $\sqrt{s}=13$ TeV by the ATLAS detector at the Large Hadron Collider. The analysis is performed by selecting two same-charge leptons, electron or muon, and at least two jets with large invariant mass and a large rapidity difference. The measured fiducial cross sections for electroweak and inclusive $W^\pm W^\pm jj$ production are $2.92 \pm 0.22\, \text{(stat.)} \pm 0.19\, \text{(syst.)}$ fb and $3.38 \pm 0.22\, \text{(stat.)} \pm 0.19\, \text{(syst.)}$ fb, respectively, in agreement with Standard Model predictions. The measurements are used to constrain anomalous quartic gauge couplings by extracting 95\%\ confidence level intervals on dimension-8 operators. A search for doubly charged Higgs bosons \(H^{\pm\pm}\) that are produced in vector-boson fusion processes and decay into a same-sign $W$ boson pair is performed. The largest deviation from the Standard Model occurs for an \(H^{\pm\pm}\) mass near $450\,\mathrm{GeV}$, with a global significance of 2.5 standard deviations.
Measurement and interpretation of same-sign $W$ boson pair production in association with two jets in $pp$ collisions at $\sqrt{s} = 13$ TeV with the ATLAS detector
CERN-LHC. A search for $W^\prime$ bosons in events with one lepton (electron or muon) and missing transverse momentum is presented. The search uses 3.2 fb$^{-1}$ of $pp$ collision data collected at $\sqrt{s} = 13$ TeV by the ATLAS experiment at the LHC in 2015. The transverse mass distribution is examined and no significant excess of events above the level expected from Standard Model processes is observed. Upper limits on the $W^\prime$ boson cross-section times branching ratio to leptons are set as a function of the $W^\prime$ mass. Assuming a $W^\prime$ boson as predicted by the Sequential Standard Model, $W^\prime$ masses below 4.07 TeV are excluded at the 95% confidence level. This extends the limit set using LHC data at $\sqrt{s}=8$ TeV by around 800 GeV.
Search for new resonances in events with one lepton and missing transverse momentum in $pp$ collisions at $\sqrt{s} = 13$ TeV with the ATLAS detector
Search for resonances decaying into a weak vector boson and a Higgs boson in the fully hadronic final state produced in proton$-$proton collisions at $\sqrt{s} = 13$ TeV with the ATLAS detector
Constraints on the Higgs boson self-coupling are set by combining double-Higgs boson analyses in the bbbb, bb$\tau\tau$ and bb$\gamma\gamma$ decay channels with single-Higgs boson analyses targeting the $\gamma\gamma$, $ZZ^{∗}$, $WW^{∗}$, $\tau\tau$ and bb decay channels. The data used in these analyses were recorded by the ATLAS detector at the LHC in proton−proton collisions at 13 TeV and correspond to an integrated luminosity of 126−139 fb$^{-1}$ . The combination of the double-Higgs analyses sets an upper limit of $\mu_{HH} < 2.4$ at 95% confidence level on the double-Higgs production cross-section normalised to its Standard Model prediction. Combining the single-Higgs and double-Higgs analyses, with the assumption that new physics affects only the Higgs boson self-coupling ($\lambda_{HHH}$), values outside the interval $-0.4< \kappa_\lambda < 6.3$ are excluded at 95% confidence level. The combined single-Higgs and double-Higgs analyses provide results with fewer assumptions, by adding in the fit more coupling modifiers introduced to account for the Higgs boson interactions with the other Standard Model particles.
Constraining the Higgs boson self-coupling from single- and double-Higgs production with the ATLAS detector using $pp$ collisions at $\sqrt{s}=13$ TeV
CERN-LHC. Measurements of the per-event charged-particle yield as a function of the charged-particle transverse momentum and rapidity are performed using $p+$Pb collision data collected by the ATLAS experiment at the LHC at a centre-of-mass energy of $\sqrt{s_{NN}}=5.02$ TeV. Charged particles are reconstructed over pseudorapidity $|\eta|<2.3$ and transverse momentum between $0.1$ GeV and $22$ GeV in a dataset corresponding to an integrated luminosity of $1$ $\mu b^{-1}$. The results are presented in the form of charged-particle nuclear modification factors, where the $p+$Pb charged-particle multiplicities are compared between central and peripheral $p+$Pb collisions as well as to charged-particle cross sections measured in pp collisions. The $p+$Pb collision centrality is characterized by the total transverse energy measured in $-4.9<\eta<-3.1$, which is in the direction of the outgoing lead beam. Three different estimations of the number of nucleons participating in the $p+$Pb collision are carried out using the Glauber model and two Glauber-Gribov colour-fluctuation extensions to the Glauber model. The values of the nuclear modification factors are found to vary significantly as a function of rapidity and transverse momentum. A broad peak is observed for all centralities and rapidities in the nuclear modification factors for charged-particle transverse momentum values around $3$ GeV. The magnitude of the peak increases for more central collisions as well as rapidity ranges closer to the direction of the outgoing lead nucleus.
Transverse momentum, rapidity, and centrality dependence of inclusive charged-particle production in $\sqrt{s_{NN}}=5.02$ TeV p+Pb collisions measured by the ATLAS experiment
CERN-LHC. This paper presents a search for direct electroweak gaugino or gluino pair production with a chargino nearly mass-degenerate with a stable neutralino. It is based on an integrated luminosity of 36.1 fb$^{-1}$ of $pp$ collisions at $\sqrt{s}$ = 13 TeV collected by the ATLAS experiment at the LHC. The final state of interest is a disappearing track accompanied by at least one jet with high transverse momentum from initial-state radiation or by four jets from the gluino decay chain. The use of short track segments reconstructed from the innermost tracking layers significantly improves the sensitivity to short chargino lifetimes. The results are found to be consistent with Standard Model predictions. Exclusion limits are set at 95% confidence level on the mass of charginos and gluinos for different chargino lifetimes. For a pure wino with a lifetime of about 0.2 ns, chargino masses up to 460 GeV are excluded. For the strong production channel, gluino masses up to 1.65 TeV are excluded assuming a chargino mass of 460 GeV and lifetime of 0.2 ns. For the strong production channel, gluino masses up to 1.65 TeV are excluded assuming a chargino mass of 460 GeV and lifetime of 0.2 ns.
Search for long-lived charginos based on a disappearing-track signature in $pp$ collisions at $\sqrt{s}$ = 13 TeV with the ATLAS detector
CERN-LHC. We present a search for magnetic monopoles and high-electric-charge objects using LHC Run 2 $\sqrt{s}$ = 13 TeV proton–proton collisions recorded by the ATLAS detector. A total integrated luminosity of 138 fb$^{−1}$ was collected by a specialized trigger and analyzed.No highly ionizing particle candidate was observed. Considering the Drell-Yan and photon-fusion pair production mechanisms as benchmark models, lowest to-date cross-section upper limits are presented for spin-0 and spin-$\frac{1}{2}$ magnetic monopoles of charge 1$g_{D}$ and 2$g_{D}$ and high-electric-charge objects of charge $20\le|z|\le100$, for masses between 200 and 4000 GeV.
Search for magnetic monopoles and stable particles with high electric charges in $\sqrt{s}=$13 TeV $pp$ collisions with the ATLAS detector
CERN-LHC. Search for lepton-flavor-violating $Z\to e\tau$ and $Z\to\mu\tau$ decays with 139 fb$^{-1}$ of Run 2 $pp$ collision data at a center-of-mass energy of 13 TeV recorded by the ATLAS detector at the LHC. This search exploits leptonically-decaying taus in the final state and is combined with a similar ATLAS search in the final state in which the tau-lepton decays hadronically using the same data set as well as Run 1 data. Final states with an opposite-sign electron-muon pair are considered. The fiducial region of the $e\tau$ channel is defined as: - Opposite-sign electron-muon pair - $p_{\mathrm{T}}(e)$ > 27 GeV - $p_{\mathrm{T}}(\mu)$ > 10 GeV - $p_{\mathrm{T}}(e)$ > $p_{\mathrm{T}}(\mu)$ - Veto on 1.37 < $|\eta(e)|$ < 1.52 - $\Delta R(e,\mu)$ > 0.1 - $|\Delta\phi(e,E^{\mathrm{miss}}_{\mathrm{T}})|$ > 1 - Visible mass $m_{\mathrm{vis}}(e,\mu)$ > 40 GeV - No $b$-jets - Transverse mass $m_{\mathrm{T}}(\mu,E^{\mathrm{miss}}_{\mathrm{T}})$ < 35 GeV The fiducial region of the $\mu\tau$ channel is defined as: - Opposite-sign electron-muon pair - $p_{\mathrm{T}}(e)$ > 15 GeV - $p_{\mathrm{T}}(\mu)$ > 27 GeV - $p_{\mathrm{T}}(\mu)$ > $p_{\mathrm{T}}(e)$ - Veto on 1.37 < $|\eta(e)|$ < 1.52 - $\Delta R(e,\mu)$ > 0.1 - $|\Delta\phi(\mu,E^{\mathrm{miss}}_{\mathrm{T}})|$ > 1 - Visible mass $m_{\mathrm{vis}}(e,\mu)$ > 40 GeV - No $b$-jets - Transverse mass $m_{\mathrm{T}}(e,E^{\mathrm{miss}}_{\mathrm{T}})$ < 35 GeV
Search for lepton-flavor-violation in $Z$-boson decays with $\tau$-leptons with the ATLAS detector
CERN-LHC. Measurements of the electroweak production of a $W$ boson in association with two jets at high dijet invariant mass are performed using $\sqrt{s} = 7$ and 8 TeV proton--proton collision data produced by the Large Hadron Collider, corresponding respectively to 4.7 and 20.2 fb${}^{-1}$ of integrated luminosity collected by the ATLAS detector. The measurements are sensitive to the production of a $W$ boson via a triple-gauge-boson vertex and include both the fiducial and differential cross sections of the electroweak process. Preselection: - Lepton $p_\text{T} > 25$ GeV - Lepton $|\eta| < 2.5$ - $E_\text{T}^\text{miss} > 25$ GeV - $m_\text{T} > 40$ GeV - $p_\text{T}^{j_1} > 80$ GeV - $p_\text{T}^{j_2} > 60$ GeV - Jet $|y| < 4.4$ - $M_{jj} > 500$ GeV - $\Delta y(j_1, j_2) > 2$ - $\Delta R(j,\ell) > 0.3$ Inclusive regions: - $M_{jj} > 0.5$ TeV, 1 TeV, 1.5 TeV, or 2 TeV Forward-lepton/central-jet region: - $N^\text{cen}_\text{lepton} = 0$, $N^\text{cen}_\text{jets} \geq 1$ Forward-lepton control region: - $N^\text{cen}_\text{lepton} = 0$, $N^\text{cen}_\text{jets} = 0$ Central-jet validation region: - $N^\text{cen}_\text{lepton} = 1$, $N^\text{cen}_\text{jets} \geq 1$ Signal region: - $N^\text{cen}_\text{lepton} = 1$, $N^\text{cen}_\text{jets} = 0$ High-mass signal region: - $M_{jj} > 1$ TeV, $N^\text{cen}_\text{lepton} = 1$, $N^\text{cen}_\text{jets} = 0$
Measurements of electroweak $Wjj$ production and constraints on anomalous gauge couplings with the ATLAS detector
CERN-LHC. The relationship between jet production in the central region and the underlying-event activity in a pseudorapidity-separated region is studied in 4.0 pb$^{-1}$ of $\sqrt{s} = 2.76$ TeV $pp$ collision data recorded with the ATLAS detector at the LHC. The underlying event is characterised through measurements of the average value of the sum of the transverse energy at large pseudorapidity downstream of one of the protons, which are reported here as a function of hard-scattering kinematic variables. The hard scattering is characterised by the average transverse momentum and pseudorapidity of the two highest transverse momentum jets in the event. The dijet kinematics are used to estimate, on an event-by-event basis, the scaled longitudinal momenta of the hard-scattered partons in the target and projectile beam-protons moving toward and away from the region measuring transverse energy, respectively. Transverse energy production at large pseudorapidity is observed to decrease with a linear dependence on the longitudinal momentum fraction in the target proton and to depend only weakly on that in the projectile proton. The results are compared to the predictions of various Monte Carlo event generators, which qualitatively reproduce the trends observed in data but generally underpredict the overall level of transverse energy at forward pseudorapidity.
Measurement of the dependence of transverse energy production at large pseudorapidity on the hard-scattering kinematics of proton-proton collisions at $\sqrt{s} = 2.76$ TeV with ATLAS
CERN-LHC. A search for new phenomena in final states characterized by high jet multiplicity, an isolated lepton (electron or muon) and either zero or at least three b-tagged jets is presented. The search uses 36.1 fb-1 of sqrt(s) = 13 TeV proton-proton collision data collected by the ATLAS experiment at the Large Hadron Collider in 2015 and 2016. The dominant sources of background are estimated using parameterized extrapolations, based on observables at medium jet multiplicity, to predict the b-tagged jet multiplicity distribution at the higher jet multiplicities used in the search. No significant excess over the Standard Model expectation is observed and 95% confidence-level limits are extracted constraining four simplified models of R-parity-violating supersymmetry that feature either gluino or top-squark pair production. The exclusion limits reach as high as 2.1 TeV in gluino mass and 1.2 TeV in top-squark mass in the models considered. In addition, an upper limit is set on the cross-section for Standard Model tttt production of 60 fb (6.5 times the Standard Model prediction) at 95% confidence level. Finally, model-independent limits are set on the contribution from new phenomena to the signal-region yields.
Search for new phenomena in a lepton plus high jet multiplicity final state with the ATLAS experiment using $\sqrt{s}$ = 13 Tev proton-proton collision data
CERN-LHC. Measurement of the inclusive isolated prompt photon cross section in pp collisions at 8 TeV with the ATLAS detector. The prompt photon fiducial region is defined as: - ET(Photon) range: 25 < ET(Photon) < 1500 GeV - |EtaPhoton|: 0-0.6, 0.6-1.37, 1.56-1.81, 1.81-2.37 - Photon Isolation in DeltaR-Cone of 0.4: ETIso < 4.8 GeV + 4.2x10^{-3} ET(Photon). At particle level it is the sum of transverse energy from all particles, except for muons, neutrinos and the photon itself. At parton level it is the sum of energy from all coloured partons.
Measurement of the inclusive isolated prompt photon cross section in $pp$ collisions at $\sqrt{s} = 8$ TeV with the ATLAS detector
A combination of searches for resonant Higgs boson pair production is presented, using up to 139 $fb^{-1}$ of $pp$ collision data at $\sqrt{s}$ = 13 TeV recorded with the ATLAS detector at the LHC. The combination includes searches performed in three decay channels: bbbb, bb$\tau\tau$, bb$\gamma\gamma$. No excess above the expected background is observed and upper limits are set at the 95% confidence level on the production cross section of Higgs boson pairs originating from the decay of a narrow scalar resonance with mass in the range 251 GeV-5 TeV. The observed (expected) limits are in the range 0.96-600 fb (1.2-390 fb). The limits are interpreted in the Type-I Two-Higgs-Doublet Model and the Minimimal Supersymmetric Standard Model, and constrain parameter space not previously excluded by other searches.
Combination of searches for resonant Higgs boson pair production using $pp$ collisions at $\sqrt{s}=13$ TeV with the ATLAS detector
CERN-LHC. Measurements of the cross section for prompt photon plus jet production in proton-proton collisions at a centre-of-mass energy of 8 TeV with 20.2/fb of data collected in 2012. The photon is required to have a transverse energy above 130 GeV and absolute value of pseudorapity |etaGamma|<2.37, excluding the region 1.37<|etaGamma|<1.56. The photon isolation is ensured by requiring the transverse energy around a cone of radius R=0.4 around the photon to be less than 10 GeV. At particle level it is the sum of transverse energy from all particles, except for muons, neutrinos and the photon itself. At parton level it is the sum of energy from all coloured partons. Jets are reconstructed using the anti-kt algorithm with radius parameter R=0.6 and required to have the jet rapidity in the range |yjet|<4.4 and the distance between the jet and the photon DeltaR(gamma jet)>1. The requirements on the jet transverse momenta depend on the sample and are as follows. Photon+1jet sample (tables 1 and 2): pTjet1 > 100 GeV. Photon+1jet sample (tables 3 to 13): pTjet1 > 100 GeV, |yjet1| < 2.37, |costhetastar| < 0.83 and |etaGamma + yjet1| < 2.37 and mgammajet1 > 467 GeV. Photon+2jet sample (tables 14 to 17): pTjet1 > 100 GeV and pTjet2 > 65 GeV. Photon+2jet sample (tables 18 and 20): pTjet1 > 100 GeV, pTjet2 > 65 GeV and 130 < ETGamma < 300 GeV. Photon+2jet sample (tables 19 and 21): pTjet1 > 100 GeV, pTjet2 > 65 GeV and ETGamma > 300 GeV. Photon+2jet sample (table 22): pTjet1 > 130 GeV, pTjet2 > 50 GeV, Delta R(gamma jet1) > 3, 1 < Delta R(jet1 jet2) < 1.5 and |etajet1| < 2.37. Photon+2jet sample (table 23): pTjet1 > 130 GeV, pTjet2 > 50 GeV, Delta R(gamma jet1) > 3, 1 < Delta R(gamma jet2) < 1.5, |etajet1| < 2.37 and pTjet2 < ETGamma. Photon+2jet sample (table 24): ratio of cross sections in tables 22 and 23. Photon+3jet sample (tables 25 to 29): pTjet1 > 100 GeV, pTjet2 > 65 GeV and pTjet3 > 50 GeV. Photon+3jet sample (tables 30, 32 and 34): pTjet1 > 100 GeV, pTjet2 > 65 GeV, pTjet3 > 50 GeV and 130 < ETGamma < 300 GeV. Photon+3jet sample (tables 31, 33 and 35): pTjet1 > 100 GeV, pTjet2 > 65 GeV, pTjet3 > 50 GeV and ETGamma > 300 GeV.
High-$E_{\rm T}$ isolated-photon plus jets production in $pp$ collisions at $\sqrt s=$ 8 TeV with the ATLAS detector
Performance of the missing transverse momentum triggers for the ATLAS detector during Run-2 data taking
CERN-LHC. A search for supersymmetry in events with large missing transverse momentum, jets, and at least one hadronically decaying tau lepton has been performed using 3.2 fb$^{-1}$ of proton-proton collision data at $\sqrt{s}=13$ TeV recorded by the ATLAS detector at the Large Hadron Collider in 2015. Two exclusive final states are considered, with either exactly one or at least two tau leptons. No excess over the Standard Model prediction is observed in the data. Results are interpreted in the context of gauge-mediated supersymmetry breaking and a simplified model of gluino pair production with tau-rich cascade decays, substantially improving on previous limits. In the GMSB model considered, supersymmetry-breaking scale ($\Lambda$) values below 92 TeV are excluded at the 95% confidence level, corresponding to gluino masses below 2000 GeV. For large values of $\tan\beta$, values of $\Lambda$ up to 107 TeV and gluino masses up to 2300 GeV are excluded. In the simplified model, gluino masses are excluded up to 1570 GeV for neutralino masses around 100 GeV. Neutralino masses up to 700 GeV are excluded for all gluino masses between 800 GeV and 1500 GeV, while the strongest exclusion of 750 GeV is achieved for gluino masses around 1400 GeV.
Search for squarks and gluinos in events with hadronically decaying tau leptons, jets and missing transverse momentum in proton-proton collisions at $\sqrt{s}=13$ TeV recorded with the ATLAS detector
A search for events with one top quark and missing transverse momentum in the final state is presented. The fully hadronic decay of the top quark is explored by selecting events with a reconstructed boosted top-quark topology produced in association with large missing transverse momentum. The analysis uses 139 fb$^{-1}$ of proton--proton collision data at a centre-of-mass energy of $\sqrt{s} =13$ TeV recorded during 2015-2018 by the ATLAS detector at the Large Hadron Collider. The results are interpreted in terms of simplified models for Dark Matter particle production and the single production of a vector-like $T$ quark.
Search for invisible particles produced in association with single top quarks in proton-proton collisions at $\sqrt{s}$=13 TeV with the ATLAS detector
CERN-LHC-ATLAS. Measurements of the cross section for $t\bar{t}\gamma$ production using the single lepton (e or mu) channel in proton-proton collisions at a centre-of-mass energy of 8 TeV with 20.2 fb^-1 of data collected in 2012. The fiducial region is defined as: - 1 electron or muon, 1 photon, at least 4 jets, at least 1 b-jet - ptLepton > 25 GeV, |etaLepton| < 2.5 - ptPhoton > 15 GeV, |etaPhoton| < 2.37 - ptJet > 25 GeV, |etaJet| < 2.5 - min(DeltaR(lepton,photon)) > 0.7 - min(DeltaR(jet,photon)) > 0.5
Measurement of the $t\bar{t}\gamma$ production cross section in proton-proton collisions at $\sqrt{s} = 8$ TeV with the ATLAS detector
CERN-LHC. A search is presented for particles that decay producing a large jet multiplicity and invisible particles. The event selection applies a veto on the presence of isolated electrons or muons and additional requirements on the number of $b$-tagged jets and the scalar sum of masses of large-radius jets. Having explored the full ATLAS 2015--2016 dataset of LHC proton--proton collisions at $\sqrt{s}$=13 TeV, which corresponds to 36.1~fb$^{-1}$ of integrated luminosity, no evidence is found for physics beyond the Standard Model.The results are interpreted in the context of simplified models inspired by R-parity-conserving and R-parity-violating supersymmetry, where gluinos are pair-produced. More generic models within the phenomenological minimal supersymmetric Standard Model are also considered.
Search for new phenomena with large jet multiplicities and missing transverse momentum using large-radius jets and flavour-tagging at ATLAS in 13 TeV $pp$ collisions
This paper presents a search for hypothetical massive, charged, long-lived particles with the ATLAS detector at the LHC using an integrated luminosity of $139 \mathrm{fb^{-1}}$ of proton--proton collisions at $\sqrt{s}=13 \text{TeV}$. These particles are expected to move significantly slower than the speed of light and should be identifiable by their high transverse momenta and anomalously large specific ionisation losses, $dE/dx$. Trajectories reconstructed solely by the inner tracking system and a $dE/dx$ measurement in the pixel detector layers provide sensitivity to particles with lifetimes down to ${\cal O}(1) \text{ns}$ with a mass, measured using the Bethe--Bloch relation, ranging from $100 \text{GeV}$ to 3 $\text{TeV}$. Interpretations for pair-production of $R$-hadrons, charginos and staus in scenarios of supersymmetry compatible with these particles being long-lived are presented, with mass limits extending considerably beyond those from previous searches in broad ranges of lifetime.
Search for heavy, long-lived, charged particles with large ionisation energy loss in $pp$ collisions at $\sqrt{s} = 13~\text{TeV}$ using the ATLAS experiment and the full Run 2 dataset
Search for new phenomena in dijet events using 37 fb$^{-1}$ of $pp$ collision data collected at $\sqrt{s}=$13 TeV with the ATLAS detector
CERN-LHC, ATLAS. A search for dark matter is conducted in final states containing a photon and missing transverse momentum in proton-proton collisions at 13 TeV. The data, collected during 2015-2018 by the ATLAS experiment at the CERN LHC, correspond to an integrated luminosity of 139 fb$^{-1}$. No deviations are observed relative to the predictions of the Standard Model. The results are interpreted as exclusion limits in models where weakly interacting dark-matter candidates are pair-produced via an axial-vector or a vector mediator in the s-channel. Results are also expressed in terms of 95% confidence level limits on the parameters of a model with an axion-like particle produced in association with a photon.
Search for dark matter in association with an energetic photon in $pp$ collisions at $\sqrt{s}$ = 13 TeV with the ATLAS detector
CERN-LHC, ATLAS. Measurements of the fiducial and total cross sections and ratios for W+/-, Z production using the electron and muon final states in proton-proton collisions at a centre-of-mass energy of 13 TeV with 81 pb^-1 of data collected in 2015. Where there are two systematic uncertainties, the first is experimental (omitting luminosity) and the second uncertainty is that of luminosity.
Measurement of $W^{\pm}$ and $Z$-boson production cross sections in $pp$ collisions at $\sqrt{s}=13$ TeV with the ATLAS detector
Study of 2-particle correlations in the context of coherent particle emission, test of the model of quantized fragmentation of a helical QCD string. Low intensity minimum bias pp data collected at centre-of-mass energy of 7 TeV. Acceptance region pT>100 MeV and |eta|<2.5. Non-identified particles, treated as pions.
Study of ordered hadron chains with the ATLAS detector
CERN-LHC. A search for heavy neutral Higgs bosons and $Z^{\prime}$ bosons is performed using a data sample corresponding to an integrated luminosity of 36.1 fb$^{-1}$ from proton-proton collisions at $\sqrt{s}$ = 13 TeV recorded by the ATLAS detector at the LHC during 2015 and 2016. The 1l1tau_h channel fiducial region is defined as: - 1e+>=1tau_h or 1mu+>=1tau_h - ptLepton > 30 GeV - |etaMuon| < 2.4, |etaEle| < 2.47 (excluding 1.37 < |etaEle| < 1.52) - ptTauVis > 25 GeV - |etaTauVis| < 2.3 (excluding 1.37 < |etaTauVis| < 1.52) - No events with more than 1 electron (ptEle > 15 GeV) or muon (ptMuon > 7 GeV, |etaMuon|<2.5) - If multiple tau_h exist, the leading visible pt one is chosen - l and tau_h opposite electric charge - |DeltaPhi(l,tau_h)| > 2.4 rad - mT(l,MET) < 40 GeV - veto 80 < m(l,tau_h) < 110 in 1e1tau_h channel The 2tau_h channel fiducial region is defined as: - >=2tau_h - ptTauVis > 65 GeV (at least one with ptTauVis > 130 GeV, note that technically, this upper threshold was 85 GeV for ~10% of the data) - No events with an electron or muon, ptLepton > 7 (15) GeV for muons (electrons), |etaMuon| < 2.5, |etaEle| < 2.47 (excluding 1.37 < |etaEle| < 1.52) - If more than two tau_h exist, the two leading visible pt ones are chosen - The two tau_h have opposite electric charge - |DeltaPhi(tau1_h,tau2_h)| > 2.7 rad For Higgs interpretations events entering the fiducial region of each channel are categorised as: - "b-tag: if they contain a b-quark initiated jet (ptJet > 20 GeV, |etaJet|<2.5)" - "b-veto: otherwise"
Search for additional heavy neutral Higgs and gauge bosons in the ditau final state produced in 36 fb$^{-1}$ of $pp$ collisions at $\sqrt{s}$ = 13 TeV with the ATLAS detector
CERN-LHC. A search for strongly produced supersymmetric particles is conducted using signatures involving multiple energetic jets and either two isolated leptons ($e$ or $\mu$) with the same electric charge or at least three isolated leptons. The search also utilises $b$-tagged jets, missing transverse momentum and other observables to extend its sensitivity. The analysis uses a data sample of proton-proton collisions at $\sqrt{s}=13$ TeV recorded with the ATLAS detector at the Large Hadron Collider in 2015 corresponding to a total integrated luminosity of 3.2 fb$^{-1}$. No significant excess over the Standard Model expectation is observed. The results are interpreted in several simplified supersymmetric models and extend the exclusion limits from previous searches. In the context of exclusive production and simplified decay modes, gluino masses are excluded at 95% confidence level up to 1.1-1.3 TeV for light neutralinos (depending on the decay channel), and bottom squark masses are also excluded up to 540 GeV. In the former scenarios, neutralino masses are also excluded up to 550-850 GeV for gluino masses around 1 TeV.
Search for supersymmetry at $\sqrt{s}=13$ TeV in final states with jets and two same-sign leptons or three leptons with the ATLAS detector
CERN-LHC. Search for new phenomena in high-mass diphoton final states using 37 fb^−1 of proton-proton collisions collected at a centre-of-mass energy of 13 TeV with the ATLAS detector in 2015 and 2016. The final states used are 2 photons. The fiducial region for the spin-0 resonance search is defined as: - 2 photons - E_T > 0.4 m_gamgam for the photon with leading E_T, and E_T > 0.3 m_gamgam for the photon with sub-leading E_T - |eta_gam| < 2.37 - An isolation requirement using all particles with lifetime greater than 10 ps at the generator level in a cone of Delta_R = 0.4 around the photon direction: E^iso_T< 0.05 E_T+ 6 GeV. For the spin-2 resonance search, the acceptance and efficiencies are assumed to be those obtained from MC simulation of KK graviton decays.
Search for new phenomena in high-mass diphoton final states using 37 fb$^{-1}$ of proton--proton collisions collected at $\sqrt{s}=13$ TeV with the ATLAS detector
This paper presents a search for pair production of higgsinos, the supersymmetric partners of the Higgs bosons, in scenarios with gauge-mediated supersymmetry breaking. Each higgsino is assumed to decay into a Higgs boson and a nearly-massless gravitino. The search targets the decay of the two Higgs bosons to $b\bar{b}$, leading to a reconstructed final state with at least three energetic $b$-jets and missing transverse momentum. Two complementary analysis channels are used, with each channel specifically targeting either low or high values of the higgsino mass. The low (high) mass channel exploits 126 (139) fb$^{-1}$ of $\sqrt{s}=13$ TeV data collected by the ATLAS detector during Run 2 of the Large Hadron Collider. No significant excess above the Standard Model prediction is found. At 95% confidence level, masses up to 940 GeV are excluded for higgsinos decaying exclusively to Higgs bosons. Exclusion limits as a function of the higgsino decay branching ratio to a Higgs boson are also reported.
Search for pair production of higgsinos in events with two Higgs bosons and missing transverse momentum in $\sqrt{s}=13$ TeV $pp$ collisions at the ATLAS experiment
We present charged-particle distributions sensitive to the underlying event, measured by the ATLAS detector in proton-proton collisions at a centre-of-mass energy of 13 TeV, in low-luminosity Large Hadron Collider fills corresponding to an integrated luminosity of 1.6 nb$^{-1}$. The distributions were constructed using charged particles with absolute pseudorapidity less than 2.5 and with transverse momentum greater than 500 MeV, in events with at least one such charged particle with transverse momentum above 1 GeV. These distributions characterise the angular distribution of energy and particle flows with respect to the charged particle with highest transverse momentum, as a function of both that momentum and of charged-particle multiplicity. The results have been corrected for detector effects and are compared to the predictions of various Monte Carlo event generators, experimentally establishing the level of underlying-event activity at LHC Run 2 energies and providing inputs for the development of event generator modelling. The current models in use for UE modelling typically describe this data to 5% accuracy, compared with data uncertainties of less than 1%.
Measurement of charged-particle distributions sensitive to the underlying event in $\sqrt{s} = 13$ TeV proton-proton collisions with the ATLAS detector at the LHC
CERN-LHC. A search for the supersymmetric partners of quarks and gluons (squarks and gluinos) in final states containing hadronic jets and missing transverse momentum, but no electrons or muons, is presented. The data used in this search were recorded in 2015 and 2016 by the ATLAS experiment in $\sqrt{s}=13\mathrm{\ Te\kern -0.1em V}$ proton--proton collisions at the Large Hadron Collider, corresponding to an integrated luminosity of 36.1 fb$^{-1}$. The results are interpreted in the context of various models where squarks and gluinos are pair-produced and the neutralino is the lightest supersymmetric particle. An exclusion limit at the 95% confidence level on the mass of the gluino is set at 2.03$\mathrm{\ Te\kern -0.1em V}$ for a simplified model incorporating only a gluino and the lightest neutralino, assuming the lightest neutralino is massless. For a simplified model involving the strong production of mass-degenerate first- and second-generation squarks, squark masses below 1.55$\mathrm{\ Te\kern -0.1em V}$ are excluded if the lightest neutralino is massless. These limits substantially extend the region of supersymmetric parameter space previously excluded by searches with the ATLAS detector.
Search for squarks and gluinos in final states with jets and missing transverse momentum using 36 fb$^{-1}$ of $\sqrt{s}$=13 TeV $pp$ collision data with the ATLAS detector
CERN-LHC, ATLAS. Measurement of jet activity in top-quark pair events produced in proton proton collisions at 13 TeV with 3.2fb-1 of data measured in 2015. Events are chosen by requiring an opposite-charge electron-muon pair and two b-tagged jets in the final state. Normalised differential cross sections are presented.
Measurement of jet activity produced in top-quark events with an electron, a muon and two $b$-tagged jets in the final state in $pp$ collisions at $\sqrt{s}=13$ TeV with the ATLAS detector
Search for supersymmetry in events with $b$-tagged jets and missing transverse momentum in $pp$ collisions at $\sqrt{s}=13$ TeV with the ATLAS detector
- Measurement of inclusive jet cross-sections with the ATLAS Detector at a centre-of-mass energy 8 TeV Inclusive jet production cross-sections are measured in proton--proton collisions at a centre-of-mass energy of $\sqrt{s}$=8 TeV recorded by the ATLAS experiment at the Large Hadron Collider at CERN. The total integrated luminosity of the analysed data set amounts to 20.2 $fb^{−1}$. Double-differential cross-sections are measured for jets defined by the anti-kt jet clustering algorithm with radius parameters of R=0.4 and R=0.6 and are presented as a function of the jet transverse momentum, in the range between 70 GeV and 2.5 TeV and in six bins of the absolute jet rapidity, between 0 and 3.0. The measured cross-sections are compared to predictions of quantum chromodynamics, calculated at next-to-leading order in perturbation theory, and corrected for non-perturbative and electroweak effects. The level of agreement with predictions, using a selection of different parton distribution functions for the proton, is quantified. Tensions between the data and the theory predictions are observed. - The HepData contain the following additional files: o) HepData base tables in yaml format for each cross-section atlas_inclusive_jet2012_r0*_eta*.yaml These files are for the default correlation scenario (see below) Sometimes up and down uncertainties can have the same sign. They need to be symmetrized for the chi2 calculation. o) Replica encoding the statistical uncertainties, e.g. to calculate the global statistical correlation matrix hepdata_tables_data_r04_replicas.tar.gz The replica can be used to calculate the statistical uncertainty. but, for convenience, the cross-section tables also contains the statistical uncertainty. The tarfile contains for each cross-section 10k replica files of the form heprep9997_R06_Eta6.txt The first number is the replica number (random), the following numbers the jet cone size and the rapidity bin In each replica file the format is as follows: The first lines are a description of the cross-section (following old HepData conventions). It includes the replica number of each file, the rapidity bin and the jet cone radius (same as in file name). The following lines with the numbers are the minimum and maximum bin edge and the fluctuated cross-section. o) The alternative splitting of the 2-points systematic uncertainties as described in the Appendix of the publication is encoded in the following tables: atlas_2012_jet_antiktr0*_incljetpt_altcorr*_eta*.yaml with the following alternative correlation scenarios For R=0.4 altcorr1 as described in Table 5 For R=0.6 altcorr1 and altcorr2 as described in Table 6 To get the chi2 values as quoted in the paper the theory systematics need to be also decorrelated as described in the paper. Note, that the splitting of the theory numbers has a large effect on the global chi2. o) Electro-weak corrections as function of jet pt (for each rapidity bins) as calculated with the method described in Dittmaier, Huss, Speckner HEP11(2012) 095 arXiv:1210.0438 are given in special tables like atlas_2012_jet_antiktr06_incljetpt_eta5_ewcorr.txt (as example for R=0.6 and 2<|y|<0.5) Each line gives the bin minimum and maximum and the correction. The corrections are given as calculated. No uncertainty is given. For some bins at high-pt the values need to be merged to compare to the measurements. o) Non-perturbative corrections (hadronisation corrections and underlying event) as function of jet pt (for each rapidity bins). See the paper for a description and references. As described in the tables the default corrections is based on Pythia8AU2CT10_PYHW tune The uncertainty based on pythia8 tunes: 4C MONASH ATLASA14NNPDF ATLASA14MRSTWLO ATLASA14CTEQL1 and on Herwig tunes. Each line gives the middle of the pt bin, the bin minimum and maximum, the default correction and the up and down uncertainty. Comments to HepData tables: o) The systematic uncertainties with the same names are correlated across the cross-sections in the various rapidity bins, (see section 6 in arXiv:1706.03192 and ATLAS-CONF-2015-037) o) The statistical uncertainty of the in situ methods (Gjet, Zjet, MJB, EtaStat ) should be treated as any other systematics uncertainty across pt and eta, but they are uncorrellated with the systematics uncertainties from a different data-set (e.g. ATLAS 2012 and ATLAS 2015 data) even if they have the same name. o) The beam uncertainty is considered as theory systematics and can be calculated from the applgrid tables. o) The corresponding applgrid files can be found on the ploughshare site https://ploughshare.web.cern.ch/ploughshare/record.php?group=atlas&dataset=atlas-atlas-incljets-8tev-arxiv-1706.03192
Measurement of the inclusive jet cross-sections in proton--proton collisions at $\sqrt{s}= $8 TeV with the ATLAS detector
SLHA files and exclusion information (in CSV format) are available to download for the pMSSM models in this paper. Please refer to this web page for download links along with a description of the contents.
ATLAS Run 2 searches for electroweak production of supersymmetric particles interpreted within the pMSSM
CERN-LHC. Measurements of normalized differential cross-sections of top-quark pair production are presented as a function of the top-quark, $t\bar{t}$ system and event-level kinematic observables in proton-proton collisions at a centre-of-mass energy of sqrt(s)=8 TeV. The observables have been chosen to emphasize the $t\bar{t}$ production process and to be sensitive to effects of initial- and final-state radiation, to the different parton distribution functions, and to non-resonant processes and higher-order corrections. Events are selected in the lepton+jets channel, requiring exactly one charged lepton and at least four jets with at least two of the jets tagged as originating from a b-quark. The measured spectra are corrected for detector effects and are compared to several Monte Carlo simulations. The results are in fair agreement with the predictions over a wide kinematic range. Nevertheless, most generators predict a harder top-quark transverse momentum distribution at high values than what is observed in the data. The agreement for this observable improves when next-to-next-to-leading order corrections are taken into account. Using the current settings and parton distribution functions, the rapidity distributions are not well modelled by any generator under consideration. However, the level of agreement is improved when more recent sets of parton distribution functions are used.
Measurements of top-quark pair differential cross-sections in the lepton+jets channel in $pp$ collisions at $\sqrt{s}=8$ TeV using the ATLAS detector
Measurement of the prompt $J/\psi$ pair production cross-section in $pp$ collisions at $\sqrt{s} = 8$ TeV with the ATLAS detector
Measurement of the $t\bar{t}$ cross section and its ratio to the $Z$ production cross section using $pp$ collisions at $\sqrt{s} = 13.6$ TeV with the ATLAS detector
Measurements of the production cross section of a $Z$ boson in association with jets in proton-proton collisions at $\sqrt{s}=13$ TeV are presented, using data corresponding to an integrated luminosity of $3.16$ fb$^{-1}$ collected by the ATLAS experiment at the CERN Large Hadron Collider in 2015. Inclusive and differential cross sections are measured for events containing a $Z$ boson boson decaying to electrons or muons and produced in association with up to seven jets with $p_{\text{T}}>30$ GeV and $|y|<2.5$. Predictions from different Monte Carlo generators based on leading-order and next-to-leading-order matrix elements for up to two additional partons interfaced with parton shower and fixed-order predictions at next-to-leading order and next-to-next-to-leading order are compared with the measured cross sections. Good agreement within the uncertainties is observed for most of the modelled quantities, in particular with the generators which use next-to-leading-order matrix elements and the more recent next-to-next-to-leading-order fixed-order predictions.
Measurements of the production cross section of a $Z$ boson in association with jets in pp collisions at $\sqrt{s} = 13$ TeV with the ATLAS detector
CERN-LHC. This paper presents a study of $WW\gamma$ and $WZ\gamma$ triboson production using events from proton--proton collisions at a centre-of-mass energy of $\sqrt{s} = 8$ TeV recorded with the ATLAS detector at the LHC and corresponding to an integrated luminosity of 20.2 fb$^{-1}$. The $WW\gamma$ production cross-section is determined using a final state containing an electron, a muon, a photon, and neutrinos ($e\nu\mu\nu\gamma$). Upper limits on the production cross-section of the $e\nu\mu\nu\gamma$ final state and the $WW\gamma$ and $WZ\gamma$ final states containing an electron or a muon, two jets, a photon, and a neutrino ($e\nu jj\gamma$ or $\mu\nu jj\gamma$) are also derived. The results are compared to the cross-sections predicted by the Standard Model at next-to-leading order in the strong-coupling constant. In addition, upper limits on the production cross-sections are derived in a fiducial region optimised for a search for new physics beyond the Standard Model. The results are interpreted in the context of anomalous quartic gauge couplings using an effective field theory. Confidence intervals at 95% confidence level are derived for the 14 coupling coefficients to which $WW\gamma$ and $WZ\gamma$ production are sensitive. The $e\nu\mu\nu\gamma$ fiducial phase space region is defined as (Table 3 of the preprint): - 1 electron and 1 muon with opposite charge and $p_{\text{T}}^{\ell} > \mbox{20 GeV} $ each - no $3^{\text{rd}}$ lepton ($p_{\text{T}}^{\ell} > \mbox{7 GeV}$) - $\eta^{\ell} < 2.5$ - $\Delta R (\ell, \ell^{\prime}) < 0.1$ - at least one photon with $E_{\text{T}}^{\gamma} > \mbox{15 GeV}$ and $|\eta^{\gamma}| < 2.37$ - isolation fraction $\epsilon_{h}^{p} < 0.5$ - $\Delta R(\ell, \gamma) > 0.5$ - $E_{\text{T,rel}}^{\text{miss}} > \mbox{15 GeV}$ - $m_{e\mu}> \mbox{50 GeV}$ - $N_{\text{jets}} = 0$ with $p_{\text{T}}^{j} > \mbox{25 GeV}$ and $|y^{j}| < 4.4$ - $\Delta R(\text{jet}, \gamma) > 0.5$ - $\Delta R(\text{jet}, \ell) > 0.3$ The $\ell\nu jj\gamma$ fiducial phase space region with $\ell = e \text{ or }\mu$ is defined as (Table 3 of the preprint): - 1 electron or 1 muon with $p_{\text{T}}^{\ell} > \mbox{25 GeV}$ and $|\eta^{\ell}| < 2.5$ - no $2^{\text{nd}}$ lepton ($p_{\text{T}}^{\ell} > \mbox{7 GeV}$) - at least one photon with $E_{\text{T}}^{\gamma} > \mbox{15 GeV}$ and $|\eta^{\gamma}| < 2.37$ - isolation fraction $\epsilon_{h}^{p} < 0.5$ - $\Delta R(\ell, \gamma) > 0.5$ - $E_{\text{T}}^{\text{miss}} > \mbox{30 GeV}$ - $m_{\text{T}} > \mbox{30 GeV}$ - at least two jets with $p_{\text{T}}^{j} > \mbox{25 GeV}$ and $|\eta^{j}| < 2.5 $ - $N_{\text{$b$-jets}} = 0$ - $|\Delta \eta_{jj}| < 1.2$ - $\Delta R_{jj} < 3.0$ - $\mbox{70 GeV} < m_{jj} < \mbox{100 GeV}$ - $\Delta R(\text{jet}, \gamma) > 0.5$ - $\Delta R(\text{jet}, \ell) > 0.3$
Study of $WW\gamma$ and $WZ\gamma$ production in $pp$ collisions at $\sqrt{s} = 8$ TeV and search for anomalous quartic gauge couplings with the ATLAS experiment
CERN-LHC. The $W$ boson angular distribution in events with high transverse momentum jets is measured using data collected by the ATLAS experiment from proton--proton collisions at a centre-of-mass energy $\sqrt{s}=$ 8 TeV at the Large Hadron Collider, corresponding to an integrated luminosity of 20.3 fb$^{-1}$. The focus is on the contributions to $W$ + jets processes from real $W$ emission, which is achieved by studying events where a muon is observed close to a high transverse momentum jet. At small angular separations, these contributions are expected to be large. Various theoretical models of this process are compared to the data in terms of the absolute cross-section and the angular distributions of the muon from the leptonic $W$ decay.
Measurement of $W$ boson angular distributions in events with high transverse momentum jets at $\sqrt{s}=$ 8 TeV using the ATLAS detector
CERN-LHC. Results of a search for physics beyond the Standard Model in events containing an energetic photon and large missing transverse momentum with the ATLAS detector at the Large Hadron Collider are reported. As the number of events observed in data, corresponding to an integrated luminosity of 36.1 fb$^{-1}$ of proton-proton collisions at a centre-of-mass energy of 13 TeV, is in agreement with the Standard Model expectations, exclusion limits in models where dark-matter candidates are pair-produced are determined. For dark-matter production via an axial-vector or a vector mediator in the s-channel, this search excludes mediator masses below 750-1200 GeV for dark-matter candidate masses below 230-480 GeV at 95% confidence level, depending on the couplings. In an effective theory of dark-matter production, the limits restrict the value of the suppression scale $M_{*}$ to be above 790 GeV at 95% confidence level. A limit is also reported on the production of a high-mass scalar resonance by processes beyond the Standard Model, in which the resonance decays to $Z\gamma$ and the $Z$ boson subsequently decays into neutrinos.
Search for dark matter at $\sqrt{s}=13$ TeV in final states containing an energetic photon and large missing transverse momentum with the ATLAS detector
CERN-LHC, ATLAS. A search for dark matter in the context of a two-Higgs-doublet model together with an additional pseudo-scalar mediator, which decays to the dark matter particles is presented. Processes where the pseudo-scalar mediator is produced in association with a single top quark are explored for the first time at the LHC. Several final states are considered, including either one or two charged leptons (electrons or muons) and a significant amount of missing transverse momentum. The analysis is based on the data collected with the ATLAS experiment at $\sqrt{s} = 13$ TeV during LHC Run 2 ($2015-2018$), corresponding to an integrated luminosity of 139 fb$^{-1}$.
Search for dark matter produced in association with a single top quark in $\sqrt{s}=13$ TeV $pp$ collisions with the ATLAS detector
Associated production of Higgs and $W$ bosons via vector-boson fusion (VBF) is highly sensitive to the relative sign of the Higgs boson couplings to $W$ and $Z$ bosons. In this Letter, two searches for this process are presented, using 140 fb$^{-1}$ of proton--proton collision data at $\sqrt{s} = 13$ TeV recorded by the ATLAS detector at the LHC. The first search targets scenarios with opposite-sign couplings of the $W$ and $Z$ bosons to the Higgs boson, while the second targets Standard Model-like scenarios with same-sign couplings. Both analyses consider Higgs decays into a pair of $b$-quarks and $W$ decays with an electron or muon. The opposite-sign coupling hypothesis is excluded with significance much greater than $5\sigma$, and the observed (expected) upper limit set on the cross-section for VBF $WH$ production is 9.0 (8.7) times the Standard Model value.
Determination of the relative sign of the Higgs boson couplings to $W$ and $Z$ bosons using $WH$ production via vector-boson fusion with the ATLAS detector
ATLAS CERN-LHC. Measurements of exclusive electron muon events in ATLAS at 8 TeV are used to estimate the exclusive cross section for W+W-, put limits on anomolous quartic couplings (aQGCs), and limit the cross section for diffractive Higgs production. The fiducial region is defined as - |etaLepton| <2.5 - ptLepton >25 (second lepton >20 or >15 for Higgs study) - exclusivity no other track associated with the electron/muon intersection with pt >0.5 The luminosity is 20.2 (0.4) 1/fb at 8 TeV. Calibration of exclusivity is data based and e e and mu mu results agree with previous measurements. The results are - dimuons > 160 GeV/c2 ratio observed/elastic predicted 3.30 (0.22) (0.06) - WW sigmaB emuX (gamma gamma) 6.9 (2.2) (1.4) pb consistent with expectation - anomolous expect pt(emu) >120 expect 0.4 see 1, limits on dim 6 and 8 - Higgs selection expect 3 see 6, UL 95% 1.2 pb
Measurement of exclusive $\gamma\gamma\rightarrow W^+W^-$ production and search for exclusive Higgs boson production in $pp$ collisions at $\sqrt{s} = 8$ TeV using the ATLAS detector
CERN-LHC. Measurement of the differential cross-section for pair production of top quarks with high transverse momentum ($p_T$), with respect to the transverse momentum of the top quark, obtained using the lepton+jets channel. The hadronically decaying top quark is reconstructed as an anti-kt jet with radius parameter R=1.0 and identified with jet substructure techniques. The measurement is obtained using 20.3 fb-1 of proton--proton collisions at a center-of-mass energy of 8 TeV and is corrected at both particle-level, in a fiducial region close to the event selection, and at parton-level, for events with top quarks with $p_T$ > 300 GeV. The fiducial region is defined as (see also Table 1 of the paper): - Exactly one lepton (e or mu) - p_T(lepton) > 25 GeV and |eta(lepton)| < 2.5 - p_T(anti-kt R=0.4 jets) > 25 GeV and |eta(anti-kt R=0.4 jets)| < 2.5 - MET > 20 GeV and MET+MTW > 60 GeV (MTW is the transverse mass between the lepton and the MET) - at least one anti-kt R=0.4 jets within Delta-R < 1.5 from the lepton - at least one anti-kt R=1.0 jets with p_T > 300 GeV, mass > 100 GeV, sqrt(d_12) > 40 GeV (sqrt(d_12) is the first splitting scale) - $\Delta R$(anti-kt R=1.0 jet, anti-kt R=0.4 jet) > 1.5 and $\Delta \phi$(anti-kt R=1.0 jet, lepton) > 2.3 - At least one of the anti-kt R=0.4 jets is b-tagged among: (a) the leading jet within $\Delta R$ < 1.5 from the lepton; (b) one jet within $\Delta R$ < 1.0 from anti-kt R=1.0 jet axis.
Measurement of the differential cross-section of highly boosted top quarks as a function of their transverse momentum in $\sqrt{s}$ = 8 TeV proton-proton collisions using the ATLAS detector
Differential cross sections are presented for the prompt and non-prompt production of the hidden-charm states $X(3872)$ and $\psi(2S)$, in the decay mode $J/\psi \pi^+\pi^-$, measured using 11.4~fb$^{-1}$ of $pp$ collisions at $\sqrt{s} = 8$~TeV by the ATLAS detector at the LHC. The ratio of cross-sections $X(3872)/\psi(2S)$ is also given, separately for prompt and non-prompt components, as well as the non-prompt fractions of $X(3872)$ and $\psi(2S)$. Assuming independent single effective lifetimes for non-prompt $X(3872)$ and $\psi(2S)$ production gives $R_B = \frac{\mathcal{B}(B \rightarrow X(3872)\textrm{ + any}) \mathcal{B}(X(3872) \rightarrow J\psi\pi^+\pi^-)}{\mathcal{B}(B \rightarrow \psi(2S)\textrm{ + any}) \mathcal{B}(\psi(2S) \rightarrow J\psi\pi^+\pi^-)} = (3.95 \pm 0.32 \mathrm{(stat)} \pm 0.08\mathrm{(sys)}) \times 10^{-2}$, while separating short- and long-lived contributions, assuming that the short-lived component is due to $B_c$ decays, gives $R_B = (3.57 \pm 0.33\mathrm{(stat)} \pm 0.11\mathrm{(sys)}) \times 10^{-2}$, with the fraction of non-prompt $X(3872)$ produced via $B_c$ decays for $p_\mathrm{T}(X(3872)) > 10$~GeV being $(25 \pm 13\mathrm{(stat)} \pm 2\mathrm{(sys)} \pm 5\mathrm{(spin)})\%$. The distributions of the dipion invariant mass in the $X(3872)$ and $\psi(2S)$ decays are also measured and compared to theoretical predictions.
Measurements of $\psi(2S)$ and $X(3872) \to J/\psi\pi^+\pi^-$ production in $pp$ collisions at $\sqrt{s} = 8$ TeV with the ATLAS detector
CERN-LHC. In the $pp \rightarrow t\bar{t}$ process the angular distributions of top and anti-top quarks are expected to present a subtle difference, which could be enhanced by processes not included in the Standard Model. This Letter presents a measurement of the charge asymmetry in events where the top-quark pair is produced with a large invariant mass. The analysis is performed on 20.3 fb$^{-1}$ of $pp$ collision data at $\sqrt{s} =$ 8 TeV collected by the ATLAS experiment at the LHC, using reconstruction techniques specifically designed for the decay topology of highly boosted top quarks. The charge asymmetry in a fiducial region with large invariant mass of the top-quark pair ($m_{t\bar{t}} > $ 0.75 TeV) and an absolute rapidity difference of the top and anti-top quark candidates within $-$2 $ < |y_t| - |y_{\bar{t}}| <$ 2 is measured to be 4.2 $\pm$ 3.2%, in agreement with the Standard Model prediction at next-to-leading order. A differential measurement in three $t\bar{t}$ mass bins is also presented.
Measurement of the charge asymmetry in highly boosted top-quark pair production in $\sqrt{s} =$ 8 TeV $pp$ collision data collected by the ATLAS experiment
CERN-LHC. The four-lepton ($4\ell$, $\ell = e, \mu$) production cross section is measured in the mass range from 80 to 1000 GeV using 20.3 fb$^{-1}$ of data in $pp$ collisions at $\sqrt{s}=8$ TeV collected with the ATLAS detector at the LHC. The $4\ell$ events are produced in the decays of resonant $Z$ and Higgs bosons and the non-resonant $ZZ$ continuum originating from $q\bar q$, $gg$, and $qg$ initial states. A total of 476 signal candidate events are observed with a background expectation of $26.2 \pm 3.6$ events, enabling the measurement of the integrated cross section and the differential cross section as a function of the invariant mass and transverse momentum of the four-lepton system. In the mass range above 180 GeV, assuming the theoretical constraint on the $q\bar q$ production cross section calculated with perturbative NNLO QCD and NLO electroweak corrections, the signal strength of the gluon-fusion component relative to its leading-order prediction is determined. The experimental fiducial region for four-lepton analysis is defined as: - 4e, 4mu or 2e2mu. - The leading dilepton pair is selected as the one with invariant mass closest to the Z-boson mass. - The sub-leading dilepton pair is selected among the remaining possible pairs with largest invariant mass. - ptLepton > 6 (7) GeV for muons (electrons). - |etaLepton| < 2.7 (2.5) for muons (electrons). - ptDilepton > 2 GeV. - ptLepton > 20, 15, 8 (10) GeV for leading, sub-leading and third muons (electrons). - min(DeltaR(l,l)) > 0.1 (0.2) for same- (different-) flavour leptons. - Leading dilepton invariant mass between 50 and 120 GeV. - Sub-leading dilepton invariant mass between 12 and 120 GeV. - All same-flavor opposite-sign lepton pairs should have invariant mass larger than 5 GeV. - Four-lepton invariant mass between 80 and 1000 GeV. UPDATE 25/04/2016: Covariance matrices were previously given without systematic uncertaintis. This mistake has been corrected.
Measurements of four-lepton production in $pp$ collisions at $\sqrt{s}=$ 8 TeV with the ATLAS detector
Search for new high-mass phenomena in the dilepton final state using 36.1 fb$^{-1}$ of proton-proton collision data at $\sqrt{s}$ = 13 TeV with the ATLAS detector
A selection of searches by the ATLAS experiment at the LHC for the electroweak production of SUSY particles are used to study their impact on the constraints on dark matter candidates. The searches use $20\,{\rm fb}^{-1}$ proton--proton collision data at $\sqrt{s}=8\,$TeV. A likelihood-driven scan of a five-dimensional effective model focusing on the gaugino--higgsino and Higgs sector of the phenomenological minimal supersymmetric Standard Model is performed. This scan uses data from direct dark matter detection experiments, the relic dark matter density and precision flavour physics results. Further constraints from the ATLAS Higgs mass measurement and SUSY searches at LEP are also applied. A subset of models selected from this scan are used to assess the impact of the selected ATLAS searches in this five-dimensional parameter space. These ATLAS searches substantially impact those models for which the mass $m({\tilde{\chi}}_0^1)$ of the lightest neutralino is less than $65\,$GeV, excluding 86\% of such models. The searches have limited impact on models with larger $m({\tilde{\chi}}_0^1)$ due to either heavy electroweakinos or compressed mass spectra where the mass splittings between the produced particles and the lightest supersymmetric particle is small.
Dark matter interpretations of ATLAS searches for the electroweak production of supersymmetric particles in $\sqrt{s} = 8$ TeV proton-proton collisions
Measurement of the $W^+W^-$ production cross section in $pp$ collisions at a centre-of-mass energy of $\sqrt{s}$ = 13 TeV with the ATLAS experiment
CERN-LHC. Measurement of tau lepton polarisation in Z-boson decays in proton-proton collisions at centre-of-mass energy of 8 TeV with 20.2 fb^-1 of data from 2012. The measurement is done in electron-hadron and muon-hadron decay channels of tau lepton pairs in a fiducial region resembling kinematical acceptance of the analysis and is extracted over the full phase-space within Z-boson mass range from 66 to 116 GeV. See: arXiv:1709.03490 [hep-ex]. The fiducial kinematic region is described as follows: - one leptonic tau decay, - one single-prong hadronic tau decay, - lepton pT > 26 GeV, - hadronic (visible) tau pT > 20 GeV, - |eta| of visible tau < 2.47 - for electron channel |eta| < 2.47 and not 1.37 < |eta| < 1.52 - for muon channel |eta| < 2.5
Measurement of $\tau$ polarisation in $Z/\gamma^{*}\rightarrow\tau\tau$ decays in proton-proton collisions at $\sqrt{s}=8$ TeV with the ATLAS detector
CERN-LHC. Measurements of charged particle distributions in proton-proton collisions at a centre-of-mass energy of 13 TeV. A data sample of nearly 9 million events recorded by the ATLAS detector during a special LHC fill with low beam currents, and thus giving a low expected mean number of interactions, is used. The charged-particle multiplicity, its dependence on transverse momentum and pseudorapidity and the dependence of the mean transverse momentum on the charged-particle multiplicity are presented. The measurements are performed with charged particles with transverse momentum greater than 500 MeV and absolute pseudorapidity less than 2.5, in events with at least one charged particle satisfying these kinematic requirements. Events with charged particles with transverse momentum greater than 500 MeV and absolute pseudorapidity less than 0.8 are also measured. The results are corrected for detector effects, presented as particle-level distributions and are compared to various Monte Carlo event generator models.
Charged-particle distributions in $\sqrt{s}=13$ TeV $pp$ interactions measured with the ATLAS detector at the LHC
CERN-LHC. The production of $W^{\pm}Z$ events in proton--proton collisions at a centre-of-mass energy of 13 TeV is measured with the ATLAS detector at the LHC. The collected data correspond to an integrated luminosity of 3.2 fb$^{-1}$. The $W^{\pm}Z$ candidates are reconstructed using leptonic decays of the gauge bosons into electrons or muons. The measured inclusive cross section in the detector fiducial region for leptonic decay modes is $\sigma_{W^\pm Z \rightarrow \ell^{'} \nu \ell \ell}^{\textrm{fid.}} = 63.2 \pm 3.2$ (stat.) $\pm 2.6$ (sys.) $\pm 1.5$ (lumi.) fb. In comparison, the next-to-leading-order Standard Model prediction is $53.4^{+3.6}_{-2.8}$ fb. The extrapolation of the measurement from the fiducial to the total phase space yields $\sigma_{W^{\pm}Z}^{\textrm{tot.}} = 50.6 \pm 2.6$ (stat.) $\pm 2.0$ (sys.) $\pm 0.9$ (th.) $\pm 1.2$ (lumi.) pb, in agreement with a recent next-to-next-to-leading-order calculation of $48.2^{+1.1}_{-1.0}$ pb. The cross section as a function of jet multiplicity is also measured, together with the charge-dependent $W^+Z$ and $W^-Z$ cross sections and their ratio. The cross sections are measured in a fiducial phase space reflecting the detector acceptance, defined by: - $p_{\mathrm{T}}$ of electrons and muons from Z0 decays > 15 GeV - $p_{\mathrm{T}}$ of electrons and muons from the $W^{\pm}$ decays > 20 GeV - $|\eta|$ of muons and electrons < 2.5 - Leptons from the Z0 boson are separated by $\Delta R(\ell,\ell) > 0.2$ from each other - Leptons from the Z0 and W bosons are separated by $\Delta R(\ell,\ell) > 0.3$ from each other - |dilepton mass - Z0 mass| < 10 GeV - $m_{\mathrm{T}}$ of $W^{\pm}$ > 30 GeV. At particle level, the kinematics of final-state prompt electrons and muons is computed including the contributions from final-state radiated photons within a distance in the ($\eta,\phi$) plane of $\Delta R = \sqrt{(\Delta\eta)^2 + (\Delta\phi)^2} = 0.1$ around the direction of the charged lepton. These dressed leptons and the final-state neutrinos that do not originate from hadron or $\tau$ decays are associated with the $W$ and $Z$ boson decay products with an algorithmic approach, called ``resonant shape''. This algorithm is based on the value of an estimator expressing the product of the nominal line shapes of the $W$ and $Z$ resonances $P = \left| \frac{1}{ m^2_{(\ell^+,\ell^-)} - \left(m_Z^{\textrm{PDG}}\right)^2 + i \; \Gamma_Z^{\textrm{PDG}} \; m_Z^{\textrm{PDG}} } \right|^2 \times \; \left| \frac {1} { m^2_{(\ell',\nu_{\ell'})} - \left(m_W^{\textrm{PDG}}\right)^2 + i \; \Gamma_W^{\textrm{PDG}} \; m_W^{\textrm{PDG}} } \right|^2$ where $m_Z^{\textrm{PDG}}$ ($m_W^{\textrm{PDG}}$) and $\Gamma_Z^{\textrm{PDG}}$ ($\Gamma_W^{\textrm{PDG}}$) are the world average mass and total width of the $Z$ ($W$) boson, respectively, as reported by the Particle Data Group. The input to the estimator is the invariant mass $m$ of all possible pairs ($\ell^+,\ell^-$) and ($\ell',\nu_{\ell'}$) satisfying the fiducial selection requirements. The final choice of which leptons are assigned to the $W$ or $Z$ bosons corresponds to the configuration exhibiting the highest value of the estimator. The inclusive cross section is also extrapolated to the total phase space and all W and Z boson decay modes. The total phase space is defined by requiring the invariant mass of the lepton pair associated with the Z boson decay to be in the range $66<m_{\ell\ell}<116$ GeV. This result is model-dependent and includes phase space that was not experimentally accessible, so it should be used with caution. Whenever possible, the fiducial cross sections should be used instead, since they are only minimally model-dependent.
Measurement of the $W^{\pm}Z$ boson pair-production cross section in $pp$ collisions at $\sqrt{s}=13$ TeV with the ATLAS Detector
CERN-LHC. Distributions of transverse momentum $p_T^{ll}$ and the angular variable $\phi^*_\eta$ of Drell--Yan lepton pairs are measured in 20.3 fb$^{-1}$ of proton--proton collisions at $\sqrt{s}=8$ TeV with the ATLAS detector at the LHC. Measurements in electron-pair and muon-pair final states are corrected for detector effects and combined in a fiducial region in which the two leptons are required to have $p_{T}>20$ GeV and $|\eta|<2.4$. Compared to previous measurements in proton--proton collisions at $\sqrt{s}=7$ TeV, these new measurements benefit from a larger data sample and improved control of systematic uncertainties. Measurements are performed in bins of lepton-pair mass above, around and below the Z-boson mass peak. UPDATE 13/06/2016: The README in the attached tarball was modified to explain the reason for a small difference between the central values of the normalised $p_T^{\ell\ell}$ distributions given in the main HEPDATA entry and those in the raw combination output given in the tarball.
Measurement of the transverse momentum and $\phi^*_{\eta}$ distributions of Drell-Yan lepton pairs in proton-proton collisions at $\sqrt{s}=8$ TeV with the ATLAS detector
A search for new resonances decaying into pairs of dijet systems is reported using the Run 2 dataset of proton-proton collisions recorded by ATLAS at at high transverse momentum.
Pursuit of paired dijet resonances in the Run 2 dataset with ATLAS
CERN-LHC. This paper presents a measurement of the W boson production cross section and the W+/W- cross-section ratio, both in association with jets, in proton-proton collisions at sqrt(s) = 8 TeV with the ATLAS experiment at the Large Hadron Collider. The measurement is performed in final states containing one electron and missing transverse momentum using data corresponding to an integrated luminosity of 20.2 fb^-1. Differential cross sections for events with at least one or two jets are presented for a range of observables, including jet transverse momenta and rapidities, the scalar sum of transverse momenta of the visible particles in the event, and the transverse momentum of the W boson. For a subset of the observables, the differential cross sections of positively and negatively charged W bosons are measured separately. In the cross-section ratio of W+/W- the dominant systematic uncertainties cancel out, improving the measurement precision by up to a factor of nine. The observables and ratios selected for this paper provide valuable input for the up quark, down quark, and gluon parton distribution functions of the proton.
Measurement of differential cross sections and $W^+/W^-$ cross-section ratios for $W$ boson production in association with jets at $\sqrt{s}=8$ TeV with the ATLAS detector
CERN-LHC. This paper presents measurements of $W^\pm Z$ production in $pp$ collisions at a center-of-mass energy of 8 TeV. The gauge bosons are reconstructed using their leptonic decay modes into electrons and muons. The data were collected in 2012 by the ATLAS experiment at the Large Hadron Collider, and correspond to an integrated luminosity of 20.3 fb$^{-1}$. The measured inclusive cross section in the detector fiducial region is $\sigma_{W^\pm Z \rightarrow \ell^{'} \nu\ \ell \ell} = 35.1 \pm$ 0.9 (stat.) $\pm 0.8$ (sys.) $\pm 0.8$ (lumi.) fb, for one leptonic decay channel. In comparison, the next-to-leading-order Standard Model expectation is 30.0 $\pm$ 2.1 fb. Cross sections for $W^+Z$ and $W^-Z$ production and their ratio are presented as well as differential cross sections for several kinematic observables. Limits on anomalous triple gauge boson couplings are derived from the transverse mass spectrum of the $W^\pm Z$ system. From the analysis of events with a $W$ and a $Z$ boson associated with two or more forward jets an upper limit at 95% confidence level on the $W^\pm Z$ scattering cross section of 0.63 fb, for each leptonic decay channel, is established, while the Standard Model prediction at next-to-leading order is 0.13 fb. Limits on anomalous quartic gauge boson couplings are also extracted The cross sections are measured in a fiducial phase space reflecting the detector acceptance, defined below. Fiducial phase space definition: - $p_{\mathrm{T}}$ of electrons and muons from Z0 decays > 15 GeV - $p_{\mathrm{T}}$ of electrons and muons from the $W^{\pm}$ decays > 20 GeV - $|\eta|$ of muons and electrons < 2.5 - Leptons from the Z0 boson are separated by $\Delta R(\ell,\ell) > 0.2$ from each other - Leptons from the Z0 and W bosons are separated by $\Delta R(\ell,\ell) > 0.3$ from each other - |dilepton mass - Z0 mass| < 10 GeV - $m_{\mathrm{T}}$ of $W^{\pm}$ > 30 GeV. At particle level, the kinematics of final-state prompt electrons and muons is computed including the contributions from final-state radiated photons within a distance in the ($\eta,\phi$) plane of $\Delta R = \sqrt{(\Delta\eta)^2 + (\Delta\phi)^2} = 0.1$ around the direction of the charged lepton. These dressed leptons and the final-state neutrinos that do not originate from hadron or $\tau$ decays are associated with the $W$ and $Z$ boson decay products with an algorithmic approach, called ``resonant shape''. This algorithm is based on the value of an estimator expressing the product of the nominal line shapes of the $W$ and $Z$ resonances $P = \left| \frac{1}{ m^2_{(\ell^+,\ell^-)} - \left(m_Z^{\textrm{PDG}}\right)^2 + i \; \Gamma_Z^{\textrm{PDG}} \; m_Z^{\textrm{PDG}} } \right|^2 \times \; \left| \frac {1} { m^2_{(\ell',\nu_{\ell'})} - \left(m_W^{\textrm{PDG}}\right)^2 + i \; \Gamma_W^{\textrm{PDG}} \; m_W^{\textrm{PDG}} } \right|^2$ where $m_Z^{\textrm{PDG}}$ ($m_W^{\textrm{PDG}}$) and $\Gamma_Z^{\textrm{PDG}}$ ($\Gamma_W^{\textrm{PDG}}$) are the world average mass and total width of the $Z$ ($W$) boson, respectively, as reported by the Particle Data Group~\cite{Agashe:2014kda}. The input to the estimator is the invariant mass $m$ of all possible pairs ($\ell^+,\ell^-$) and ($\ell',\nu_{\ell'}$) satisfying the fiducial selection requirements defined in the next paragraph. The final choice of which leptons are assigned to the $W$ or $Z$ bosons corresponds to the configuration exhibiting the highest value of the estimator. The inclusive cross section is also extrapolated to the total phase space and all W and Z boson decay modes. This result is model-dependent and includes phase space that was not experimentally accessible, so it should be used with caution. Whenever possible, the fiducial cross sections should be used instead, since they are only minimally model-dependent. Fiducial phase space for VBS measurement: additional criteria to the above Fiducial phase space definition - at least 2 jets - $p_{\mathrm{T}}$ of jets > 30 GeV - $|\eta|$ of jets < 4.5 - invariant mass of the 2 leading jets > 500 GeV - leptons and jets separated by $\Delta R(\ell,jet) > 0.3$ where jets are particle level jets with anti-kt R=0.4. Fiducial phase space for aQGC measurement: additional criteria to the above VBS phase space definition - difference in azimuthal angle between W and Z bosons directions $|\Delta \phi(W,Z)| > 2$ - scalar sum of the transverse momenta of the three charged leptons associated with W and Z bosons $\sum |p_{\mathrm{T}}^{\ell}| > 250$ GeV.
Measurements of $W^\pm Z$ production cross sections in $pp$ collisions at $\sqrt{s} = 8$ TeV with the ATLAS detector and limits on anomalous gauge boson self-couplings
CERN-LHC. A measurement of the correlations between the polar angles of leptons from the decay of pair-produced $t$ and $\bar{t}$ quarks in the helicity basis is reported, using proton-proton collision data collected by the ATLAS detector at the LHC. The dataset corresponds to an integrated luminosity of 4.6fb$^{-1}$ at a center-of-mass energy of $\sqrt{s}=7$ TeV collected during 2011. Candidate events are selected in the dilepton topology with large missing transverse momentum and at least two jets. The angles $\theta_1$ and $\theta_2$ between the charged leptons and the direction of motion of the parent quarks in the $t\bar{t}$ rest frame are sensitive to the spin information, and the distribution of $\cos\theta_1\cdot\cos\theta_2$ is sensitive to the spin correlation between the $t$ and $\bar{t}$ quarks. The distribution is unfolded to parton level and compared to the next-to-leading order prediction. A good agreement is observed.
Measurement of the correlations between the polar angles of leptons from top quark decays in the helicity basis at $\sqrt{s}=7$TeV using the ATLAS detector
CERN-LHC. This paper describes a measurement of fiducial and differential cross sections of gluon-fusion Higgs boson production in the H->WW*->e nu mu nu channel, using 20.3 fb^{-1} of proton--proton collision data. The data were produced at a centre-of-mass energy of sqrt(s) = 8 TeV at the CERN Large Hadron Collider and recorded by the ATLAS detector in 2012. Cross sections are measured from the observed H->WW*->e nu mu nu signal yield in categories distinguished by the number of associated jets. The total cross section is measured in a fiducial region defined by the kinematic properties of the charged leptons and neutrinos. Differential cross sections are reported as a function of the number of jets, the Higgs boson transverse momentum, the dilepton rapidity, and the transverse momentum of the leading jet. The jet-veto efficiency, or fraction of events with no jets above a given transverse momentum threshold, is also reported. All measurements are compared to QCD predictions from Monte Carlo generators and fixed-order calculations, and are in agreement with the Standard Model predictions. The fiducial region is defined as: - 1 electron, 1 muon, 2 neutrinos, n jets - electron: pT> 15 GeV, |eta|< 1.37 or 1.52< |eta|< 2.47 - muon: pT> 15 GeV, |eta|< 2.5 - jets: pT> 25 GeV if |eta|< 2.4, pT> 30 GeV if 2.4 <|eta|< 4.5 - leading lepton: pT> 22 GeV - 10 < M(e,mu) < 55 GeV - Delta_Phi(e,mu) < 1.8 - missing transeverse momentum > 20 GeV.
Measurement of fiducial differential cross sections of gluon-fusion production of Higgs bosons decaying to $WW^{\ast}{\rightarrow\,}e\nu\mu\nu$ with the ATLAS detector at $\sqrt{s}=8$ TeV
CERN-LHC. A search for physics beyond the Standard Model, in final states with at least one high transverse momentum charged lepton (electron or muon) and two additional high transverse momentum leptons or jets, is performed using 3.2 fb^-1 of proton--proton collision data recorded by the ATLAS detector at the Large Hadron Collider in 2015 at sqrt(s) = 13 TeV. The upper end of the distribution of the scalar sum of the transverse momenta of leptons and jets (sumPT) is sensitive to the production of high-mass objects.
Search for TeV-scale gravity signatures in high-mass final states with leptons and jets with the ATLAS detector at $\sqrt{s}=13$ TeV
Unfolded soft drop jet mass distributions for dijet events.
A measurement of the soft-drop jet mass in pp collisions at $\sqrt{s} = 13$ TeV with the ATLAS detector
Three searches for the direct production of staus or charginos and neutralinos in final states with at least two hadronically decaying $\tau$-leptons are presented. For chargino and neutralino production, decays via intermediate staus or $Wh$ bosons are considered. The analysis uses a dataset of $pp$ collisions corresponding to an integrated luminosity of $139\,$fb$^{-1}$, recorded with the ATLAS detector at the Large Hadron Collider at a centre-of-mass energy of 13 TeV. No significant deviation from the expected Standard Model background is observed and SUSY particle mass limits at 95\% confidence level are obtained in simplified models. For direct production of $\tilde{\chi}_1^{+}\tilde{\chi}_1^{-}$, chargino masses are excluded up to 970 GeV, while $\tilde{\chi}_1^{\pm}$ and $\tilde{\chi}_2^{0}$ masses up to 1160 GeV (330 GeV) are excluded for $\tilde{\chi}_1^{\pm}\tilde{\chi}_2^{0}$/$\tilde{\chi}_1^{+}\tilde{\chi}_1^{-}$ production decaying via staus ($Wh$ bosons). Stau masses up to 500 GeV are excluded for mass degenerate $\tilde{\tau}_{L,R}$ scenarios and up to 425 GeV for $\tilde{\tau}_L$-only scenarios. The first sensitivity to $\tilde{\tau}_R$-only scenarios from the ATLAS experiment is presented here, with $\tilde{\tau}_R$ masses excluded up to 350 GeV.
Search for electroweak production of supersymmetric particles in final states with two $\tau$-leptons in $\sqrt{s}$ = 13 TeV $pp$ collisions with the ATLAS detector
Search for associated production of a $Z$ boson with an invisibly decaying Higgs boson or dark matter candidates at $\sqrt{s}=13$ TeV with the ATLAS detector
Differential cross-section measurements of the production of four charged leptons in association with two jets using the ATLAS detector
The $t\bar{t}$ production cross-section is measured in the lepton+jets channel using proton-proton collision data at a centre-of-mass energy of $\sqrt{s}=13$ TeV collected with the ATLAS detector at the LHC. The dataset corresponds to an integrated luminosity of 139 fb$^{-1}$. Events with exactly one charged lepton and four or more jets in the final state, with at least one jet containing $b$-hadrons, are used to determine the $t\bar{t}$ production cross-section through a profile-likelihood fit. The inclusive cross-section is measured to be ${\sigma_{\text{inc}} = 830 \pm 0.4 \text{(stat.)} \pm 36 \text{(syst.)}\pm 14 \text{(lumi.)} \mathrm{pb}}$ with a relative uncertainty of 4.6 %. The result is consistent with theoretical calculations at next-to-next-to-leading order in perturbative QCD.
Measurement of the $t\bar{t}$ production cross-section in the lepton+jets channel at $\sqrt{s}=13\;$TeV with the ATLAS experiment
A measurement of single top-quark production in the s-channel is performed in proton--proton collisions at a centre-of-mass energy of $13$ TeV with the ATLAS detector at the CERN Large Hadron Collider. The dataset corresponds to an integrated luminosity of 139 fb$^{-1}$. The analysis is performed on events with an electron or muon, missing transverse momentum and exactly two $b$-tagged jets in the final state. A discriminant based on matrix element calculations is used to separate single top-quark s-channel events from the main background contributions, which are top-quark pair production and $W$-boson production in association with jets. The observed (expected) signal significance over the background-only hypothesis is 3.3 (3.9) standard deviations, and the measured cross-section is $\sigma=8.2^{+3.5}_{-2.9}$ pb, consistent with the Standard Model prediction of $\sigma^{\mathrm{SM}}=10.32^{+0.40}_{-0.36}$ pb.
Measurement of single top-quark production in the s-channel in proton$-$proton collisions at $\mathrm{\sqrt{s}=13}$ TeV with the ATLAS detector
CERN-LHC. Results are reported of a search for new phenomena, such as supersymmetric particle production, that could be observed in high-energy proton--proton collisions. Events with large numbers of jets, together with missing transverse momentum from unobserved particles, are selected. The data analysed were recorded by the ATLAS experiment during 2015 using the 13 TeV centre-of-mass proton--proton collisions at the Large Hadron Collider, and correspond to an integrated luminosity of 3.2 fb$^{-1}$. The search selected events with various jet multiplicities from $\ge 7$ to $\ge 10$ jets, and with various $b$-jet multiplicity requirements to enhance sensitivity. No excess above Standard Model expectations is observed. The results are interpreted within two supersymmetry models, where gluino masses up to 1400 GeV are excluded at 95% confidence level, significantly extending previous limits.
Search for new phenomena in final states with large jet multiplicities and missing transverse momentum with ATLAS using $\sqrt{s} =13$ TeV proton--proton collisions
CERN-LHC. Measurements of normalized differential cross-sections of top quark pair ($t\bar t$) production are presented as a function of the mass, the transverse momentum and the rapidity of the $t\bar t$ system in proton-proton collisions at center-of-mass energies of $\sqrt{s}$ = 7 TeV and 8 TeV. The dataset corresponds to an integrated luminosity of 4.6 fb$^{-1}$ at 7 TeV and 20.2 fb$^{-1}$ at 8 TeV, recorded with the ATLAS detector at the Large Hadron Collider. Events with top quark pair signatures are selected in the dilepton final state, requiring exactly two charged leptons and at least two jets with at least one of the jets identified as likely to contain a $b$-hadron. The measured distributions are corrected for detector effects and selection efficiency to cross-sections at the parton level. The differential cross-sections are compared with different Monte Carlo generators and theoretical calculations of $t\bar t$ production. The results are consistent with the majority of predictions in a wide kinematic range.
Measurement of top quark pair differential cross-sections in the dilepton channel in $pp$ collisions at $\sqrt{s}$ = 7 and 8 TeV with ATLAS