Jet Fragmentation Function Moments in Heavy Ion Collisions

TL;DR

This paper proposes using moments of the jet fragmentation function in heavy-ion collisions to better understand jet quenching, offering a method resilient to background noise and fluctuations.

Contribution

It introduces a novel approach of using fragmentation function moments for jet analysis, improving background subtraction and correction for fluctuations in heavy-ion collisions.

Findings

Moments of the fragmentation function are as sensitive to quenching as the function itself.

Background subtraction techniques can be effectively applied to moments.

Corrections for background-fluctuation correlations are straightforward.

Abstract

The nature of a jet's fragmentation in heavy-ion collisions has the potential to cast light on the mechanism of jet quenching. However the presence of the huge underlying event complicates the reconstruction of the jet fragmentation function as a function of the momentum fraction z of hadrons in the jet. Here we propose the use of moments of the fragmentation function. These quantities appear to be as sensitive to quenching modifications as the fragmentation function directly in z. We show that they are amenable to background subtraction using the same jet-area based techniques proposed in the past for jet p_t's. Furthermore, complications due to correlations between background-fluctuation contributions to the jet's p_t and to its particle content are easily corrected for.