Momentum Spectra in the Current Region of the Breit Frame in Deep Inelastic Scattering at HERA

TL;DR

This paper measures charged particle spectra in deep inelastic scattering at HERA, comparing results to $e^+e^-$ data and QCD calculations, revealing universality at high $Q^2$ but discrepancies at low $Q^2$.

Contribution

It provides the first detailed analysis of momentum spectra evolution in the Breit frame's current region, testing QCD predictions and universality in DIS.

Findings

Results support universality of spectra at high $Q^2$

Discrepancies observed at low $Q^2$ with theoretical models

Comparison with $e^+e^-$ data confirms similar fragmentation patterns

Abstract

The production of charged particles has been measured in deep inelastic scattering (DIS) with the ZEUS detector. The evolution of the moments of the scaled momenta distributions in $Q^2$ and $x$ has been investigated in the current fragmentation region of the Breit frame. The results in the current region are compared to $e^+e^-$ data and QCD analytical calculations. The results are consistent with the universality of single-particle spectra in DIS and $e^+e^-$ annihilation at high $Q^2.$ The results at low $Q^2$ disagree with analytical calculations based on the modified leading log approximation (MLLA) and local parton hadron duality (LPHD).