Measurement of the differential cross section of photon plus jet production in ppbar collisions at sqrt{s}=1.96 TeV

TL;DR

This paper measures the differential cross section of photon plus jet production in proton-antiproton collisions at 1.96 TeV, comparing results with NLO QCD calculations and Monte Carlo simulations to test theoretical models.

Contribution

It provides the first detailed measurement of photon plus jet differential cross sections at Tevatron energies, testing the accuracy of NLO QCD and event generators.

Findings

NLO QCD generally agrees with data but misses some regions.

Differential cross sections vary with photon and jet rapidities.

Monte Carlo predictions show partial agreement with measurements.

Abstract

We study the process of associated photon and jet production, p+pbar --> photon + jet + X, using 8.7 fb^-1 of integrated luminosity collected by the D0 detector at the Fermilab Tevatron Collider at a center-of-mass energy sqrt{s}=1.96 TeV. Photons are reconstructed with rapidity |y^gamma| <1.0 or 1.5<|y^{gamma}| < 2.5 and transverse momentum pT^gamma GeV. The highest-p_T jet is required to be in one of four rapidity regions up to |y^{jet}|< 3.2. For each rapidity configuration we measure the differential cross sections in pT_gamma separately for events with the same sign (y^{gamma} y^{jet}}>0) and opposite sign (y^{gamma} y^{jet}<=0) of photon and jet rapidities. We compare the measured triple differential cross sections, d^3 sigma / d pT_gamma y^{gamma} y^{jet}, to next-to-leading order (NLO) perturbative QCD calculations using different sets of parton distribution functions and to predictions from the SHERPA and PYTHIA Monte Carlo event generators. The NLO calculations are found to be in general agreement with the data, but do not describe all kinematic regions.