Forward jet production in deep inelastic ep scattering and low-x parton dynamics at HERA

TL;DR

This paper measures inclusive jet cross sections in deep inelastic ep scattering at HERA to investigate low-x parton dynamics, revealing the significance of higher-order QCD corrections in accurately modeling forward jet production.

Contribution

It provides the first detailed comparison of forward jet data with fixed-order QCD calculations including alpha_s^2 corrections, emphasizing their importance at low x.

Findings

Leading-order QCD underestimates data by up to an order of magnitude at low x.

Including alpha_s^2 corrections improves the agreement with measurements.

Results highlight the relevance of t-channel gluon-exchange diagrams in low-x parton dynamics.

Abstract

Differential inclusive jet cross sections in neutral current deep inelastic ep scattering have been measured with the ZEUS detector. Three phase-space regions have been selected in order to study parton dynamics where the effects of BFKL evolution might be present. The measurements have been compared to the predictions of leading-logarithm parton shower Monte Carlo models and fixed-order perturbative QCD calculations. In the forward region, QCD calculations at order alpha_s^1 underestimate the data up to an order of magnitude at low x. An improved description of the data in this region is obtained by including QCD corrections at order alpha_s^2, which account for the lowest-order t-channel gluon-exchange diagrams, highlighting the importance of such terms in parton dynamics at low x.