Measurement of the Inclusive Di-Jet Cross Section in Photoproduction and Determination of an Effective Parton Distribution in the Photon

TL;DR

This paper measures the inclusive di-jet cross section in photoproduction at HERA, providing insights into the photon’s parton distribution and confirming QCD predictions about scale dependence.

Contribution

It presents the first measurement of the di-jet cross section as a function of jet energy and extracts an effective parton distribution in the photon at high energies.

Findings

Cross section measurements align with QCD predictions.

Effective parton distribution determined at large fractional energies.

Results support the logarithmic scale dependence in perturbative QCD.

Abstract

The double-differential inclusive di-jet cross section in photoproduction processes is measured with the H1 detector at HERA. The cross section is determined as a function of the average transverse jet energy E_T^jets for ranges of the fractional energy x_gamma^jets of the parton from the photon side. An effective leading order parton distribution in the photon is determined at large parton fractional energies for scales between 80<p_T^2<1250 GeV^2. The measurement is compatible with the logarithmic scale dependence that is predicted by perturbative QCD.