Transverse momentum broadening at NLO and QCD evolution of $\hat{q}$

Abstract

Within the framework of a high-twist approach, we show the first complete next-to-leading order calculation of transverse momentum broadening in semi-inclusive deeply inelastic $e+A$ scattering and Drell-Yan dilepton production in $p+A$ collisions. We demonstrate at one-loop level how QCD factorization holds for multiple scattering in nuclear medium, and the university of the associated quark-gluon correlation function. Our calculation also identifies QCD evolution equation for the quark-gluon correlation function, which determines the QCD factorization scale and energy dependence of jet transport parameter $\hat{q}$.

Comments: talk presented by Hongxi Xing at the XXIV Quark Matter conference, May 19-24 2014, Darmstadt (Germany)