Deep inelastic prompt photon production at HERA in the kt-factorization approach

TL;DR

This paper studies prompt photon production in deep inelastic scattering at HERA using the kt-factorization approach, accounting for off-shell effects and comparing predictions with experimental data.

Contribution

It introduces a detailed kt-factorization calculation for prompt photon production, including quark radiation, and compares results with HERA data, highlighting the enhanced QQ mechanism.

Findings

Quark radiation subprocess contribution is increased in kt-factorization.

Predictions agree with H1 and ZEUS experimental data.

The approach provides a conservative error analysis.

Abstract

We investigate the prompt photon production in deep inelastic scattering at HERA in the framework of kt-factorization QCD approach. Our study is based on the off-shell partonic amplitude e q* -> e gamma q, where the photon radiation from the leptons as well as from the quarks is taken into account. The unintegrated quark densities in a proton are determined using the Kimber-Martin-Ryskin prescription. The conservative error analisys is performed. We investigate both inclusive and jet associated prompt photon production rates. Our predictions are compared with the recent experimental data taken by the H1 and ZEUS collaborations. We demonstrate that in the kt-factorization approach the contribution from the quark radiation subprocess (QQ mechanism) is enhanced as compared to the leading-order collinear approximation.