Observation of Scaling Violations in Scaled Momentum Distributions at HERA

TL;DR

This paper reports measurements of charged particle production in deep inelastic scattering at HERA, revealing clear scaling violations in scaled momentum distributions as a function of the momentum transfer squared, $Q^2$.

Contribution

It provides the first single-experiment evidence of scaling violations in scaled momentum distributions over a wide $Q^2$ range in DIS.

Findings

Evidence of scaling violations in scaled momentum distributions.

Measurements span $Q^2$ from 10 to 1280 GeV^2.

Results support QCD predictions of scaling violations.

Abstract

Charged particle production has been measured in deep inelastic scattering (DIS) events over a large range of $x$ and $Q^2$ using the ZEUS detector. The evolution of the scaled momentum, $x_p$, with $Q^2,$ in the range 10 to 1280 $GeV^2$, has been investigated in the current fragmentation region of the Breit frame. The results show clear evidence, in a single experiment, for scaling violations in scaled momenta as a function of $Q^2$.