Modified DGLAP Evolution for Fragmentation Functions in Nuclei and QGP

TL;DR

This paper develops and numerically solves a modified DGLAP evolution framework incorporating medium effects, to study fragmentation functions in nuclear and quark-gluon plasma environments, revealing significantly increased parton densities in hot media.

Contribution

It introduces a generalized factorization approach with modified splitting functions and applies it to hot nuclear matter using realistic geometries and hydrodynamics.

Findings

Parton density in hot medium is about 30 times larger than in cold nucleons.

Medium-modified fragmentation functions differ significantly from vacuum ones.

The model successfully describes DIS and heavy-ion collision data.

Abstract

Within the framework of generalized factorization of higher-twist contributions, including modification to splitting functions of both quark and gluon, we get and numerically resolve the medium-modified DGLAP (mDGLAP) evolution equations. With Woods-Saxon nuclear geometry and Hirano 3D ideal hydrodynamic simulations of hot medium, we study the medium modified fragmentation functions (mFF) in DIS and Au+Au collisions in RHIC. Our calculation imply that the parton density in hot medium produced in RHIC is about 30 times larger than cold nucleon.