Quark energy loss in semi-inclusive deep inelastic scattering of leptons on nuclei

TL;DR

This paper investigates quark energy loss in nuclear media during semi-inclusive deep inelastic scattering, analyzing experimental data to quantify energy loss per unit length and comparing models of linear and quadratic dependence.

Contribution

It provides a leading-order analysis of quark energy loss effects on hadron multiplicity ratios, with a global fit estimating energy loss per unit length.

Findings

Energy loss per unit length is 0.38 1 0.03 GeV/fm.

Theoretical results agree with experimental data when considering nuclear modification of fragmentation functions.

The dependence of energy loss on path length (linear or quadratic) remains undetermined.

Abstract

Semi-inclusive deep inelastic scattering on nuclear targets is an ideal tool to study the energy loss effect of an outgoing quark in a nuclear medium. By means of the short hadron formation time, the experimental data with quark hadronization occurring outside the nucleus are picked out. A leading-order analysis is performed for the hadron multiplicity ratios as a function of the energy fraction on helium, neon, and copper nuclei relative to deuteron for the various identified hadrons. It is shown that the nuclear effects on parton distribution functions can be neglected. It is found that the theoretical results considering the nuclear modification of fragmentation functions due to quark energy loss are in good agreement with the experimental data. Whether the quark energy loss is linear or quadratic with the path length is not determined. The obtained energy loss per unit length is 0.38 \pm 0.03 GeV/fm for an outgoing quark by the global fit.