Precise QCD Predictions for Photon-Associated Hadron Production at the LHC

Abstract

Prompt-photon production with recoiling QCD radiation is crucial for new-physics searches, determinations of parton distribution and fragmentation functions, and jet-quenching studies in heavy-ion collisions. We present the first fully differential NNLO QCD predictions for photon-associated identified-hadron production at the LHC. We compare predictions obtained with different fragmentation function (FF) sets to ALICE and ATLAS data at $\sqrt{s}=5.02\,{\rm TeV}$. Our calculation provides an important theoretical ingredient for FF global fits and offers a precision proton--proton baseline for photon-tagged heavy-ion studies.