Systematic study of the jet fragmentation function for inclusive jet-production in p+p collisions at sqrt{s}=200 GeV in STAR

TL;DR

This paper presents the first measurements of charged hadron and particle-identified jet fragmentation functions in p+p collisions at 200 GeV, providing a baseline for understanding jet quenching in heavy ion collisions.

Contribution

It offers the first experimental data on fragmentation functions in p+p at RHIC energies, comparing results with PYTHIA simulations and exploring dependence on jet parameters.

Findings

Fragmentation functions are consistent with PYTHIA/MLLA predictions.

Jet cone-size and energy dependence are characterized.

Baseline data for heavy ion collision studies are established.

Abstract

Jet fragmentation functions measured in e^+e^- and p+\bar{p} experiments are well-described on an inclusive hadron level by QCD-based calculations. Fragmentation is expected to be modified by the presence of a strongly interacting medium, but full theoretical description of this modification must still be developed. It has recently been suggested that particle-identified fragmentation functions may provide additional insight into the processes underlying jet quenching. To assess the applicability of QCD-based fragmentation calculations to RHIC data, and to provide a baseline with which to compare fragmentation function measurements in heavy ion collisions, we present the first measurements of charged hadron and particle-identified fragmentation functions of jets reconstructed via a midpoint-cone algorithm from p+p collisions at 200 GeV in STAR. We study the dependence on jet cone-size and jet-energy, and compare the results to PYTHIA simulations based on the Modified Leading Log Approximation (MLLA).