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.
