QCD Evolution of Nuclear Quark-Gluon Correlation Function

Hongxi Xing,Xin-Nian Wang,Enke Wang,Zhong-Bo Kang

doi:10.1142/s2010194515600617

Abstract

We summarize the results on the next-to-leading order (NLO) calculations of transverse momentum broadening in semi-inclusive deeply inelastic e + A scattering (SIDIS) and Drell-Yan dilepton production (DY) in p + A collisions. The corresponding transverse momentum weighted differential cross sections are shown to factorize at NLO. Our calculations identify the QCD evolution equation for the quark-gluon correlation function, and also confirm the universality of the associated quark-gluon correlation function in SIDIS and DY. The evolution equation can be further applied to determine the QCD factorization scale and the energy dependence of the jet transport parameter [Formula: see text].

Highlights

There have been a lot of efforts focused on the QCD evolution of leading-twist parton distribution functions, which are very successful in interpreting the data from high energy experiments of e + p and p + p collisions
We summarize the results on the next-to-leading order (NLO) calculations of transverse momentum broadening in semi-inclusive deeply inelastic e + A scattering (SIDIS) and Drell-Yan dilepton production (DY) in p + A collisions
We demonstrate through explicit calculation at NLO how QCD factorization holds for multiple parton scattering

Summary

Introduction

There have been a lot of efforts focused on the QCD evolution of leading-twist parton distribution functions, which are very successful in interpreting the data from high energy experiments of e + p and p + p collisions. At a complete NLO computation, one will encounter various divergences, which should be properly regularized to the corresponding nonperturbative functions, so that the long and short distance physics can be factorized This is an issue of QCD factorization of multiple scattering,[8] which provides a solid baseline in extracting the multi-parton correlation functions in the nuclear medium. This is largely due to the complexity of QCD dynamics for multiple scattering, which involves both initial-state and final-state interactions and medium evolution In this contribution, we show the first complete NLO calculation of transverse momentum broadening in SIDIS9, 10 and DY in p + A collisions.[11] In these two processes, we have either a virtual photon prepared in the initial state or observed in the final state, one can always concentrate on one particular multiple scattering effect (either initial-state or final-state) to simplify the evaluation,[12, 13] and to make the analysis of QCD factorization for multiple scattering more clear. The transverse momentum broadening in these two processes have been studied experimentally at DESY, Jlab and FNAL, and will be further investigated in the ongoing experiments at RHIC and LHC, and the future planned programs at EIC

NLO Transverse Momentum Broadening and QCD Factorization in SIDIS and DY

Conclusions