Jet Energy Shift due to Non-Perturbative QCD Effects in p+p Collisions Studied with PYTHIA

Utilizing PYTHIA we study non-pertubative QCD effects to jet transverse momentum shift in hadronic collisions at the RHIC and the LHC. The dependences of non-perturbative effects such as hadronization corrections and underlying event effect on jet radius R, colliding energy, color factor, transverse momentum are investigated by numerical simulations. Hadronization corrections give a negative contribution to the jet energy shift and its magnitude decreases with jet E_T and colliding energy √s as well as jet radius R. However, the underlying event effect gives a positive contribution to the jet energy shift and its contribution increases with jet radius and √s. Hadronization and underlying event effect offset each other and could be canceled completely at a specific jet radius dubbed R_NP=0. It is observed that R_NP=0 decreases with colliding energy √s and is larger for a gluon jet than a quark jet at any fixed E_T.