Dihadron fragmentation: in vacuum and in matter

TL;DR

This paper investigates how dihadron fragmentation functions are altered in nuclear matter and heavy-ion collisions, revealing weak suppression in DIS and moderate enhancement in heavy-ion near-side correlations.

Contribution

It introduces a framework for medium-modified dihadron fragmentation functions accounting for gluon bremsstrahlung and multiple scattering effects.

Findings

Weak nuclear suppression of dihadron ratios in DIS experiments.

Moderate medium enhancement of near-side high pT hadron correlations in heavy-ion collisions.

Modified fragmentation functions closely follow single hadron behavior.

Abstract

Two particle correlations within a single jet produced in deeply inelastic scattering (DIS) off a large nucleus as well as in heavy-ion collisions are explored. This is performed within the framework of the medium modified dihadron fragmentation functions. The modification occurs due to gluon bremsstrahlung induced by multiple scattering. The modified fragmentation functions for dihadrons are found to follow closely that of single hadrons leading to a weak nuclear suppression of their ratios as measured by HERMES in DIS experiments. Meanwhile, a moderate medium enhancement of the near-side correlation of two high $p_T$ hadrons is found in central heavy-ion collisions, partially due to trigger bias caused by the competition between parton energy loss and the initial Cronin effect.