Constraints on the intrinsic charm content of the proton from recent ATLAS data

Abstract

We investigate the possibility to constrain the intrinsic charm probability $$w_{\mathrm{c} {\bar{{\mathrm{c}}}}}= P_{{\mathrm{c}{\bar{\mathrm{c}}}} /\mathrm{p}}$$ using first ATLAS data on the associated production of prompt photons and charm-quark jets in pp collisions at $$\sqrt{s} = 8$$ TeV. The upper limit $$w_{\mathrm{c} {\bar{{\mathrm{c}}}}}< 1.93$$ % is obtained at the 68 % confidence level. This constraint is primarily determined from the theoretical scale and systematical experimental uncertainties. Suggestions for reducing these uncertainties are discussed. The implications of intrinsic heavy quarks in the proton for future studies at the LHC are also discussed.