INSPIRE Georges Aad Brad Abbott Dale Charles Abbott Adam Abed Abud Kira Abeling Deshan Kavishka Abhayasinghe Syed Haider Abidi Ossama Abouzeid Nicola Abraham Halina Abramowicz 2025-11-17 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. https://service.tib.eu/vdataset/inspirehep_ed35122d-8b0c-40d3-be82-92ad95124602 en INSPIRE-HEP Search for dark matter in association with an energetic photon in $pp$ collisions at $\sqrt{s}$ = 13 TeV with the ATLAS detector dataset