Sensitivity of the LHC isolated-gamma+jet data to the parton distribution functions of the proton

L. Carminati, G. Costa, D. d'Enterria, I. Koletsou, G. Marchiori, J. Rojo, M. Stockton, F. Tartarelli

Published 2012-12-21, updated 2013-04-02Version 2

We study the impact of differential isolated-photon+jet cross sections measured in proton-proton collisions at a center-of-mass energy of sqrt{s} = 7 TeV on the parton distribution functions (PDF) of the proton. Next-to-leading order perturbative QCD (pQCD) calculations complemented with the NNPDF2.1 parton densities, and a Bayesian PDF reweighting method are employed. We find that although the current data provide only mild constraints to the parton densities, future gamma-jet measurements with reduced experimental uncertainties can improve our knowledge of the gluon density over a wide range of parton fractional momenta x as well as of the quarks at low-x.