Measurement of Deeply Virtual Compton Scattering and its t-dependence at HERA

TL;DR

This paper reports on the measurement of elastic deeply virtual Compton scattering at HERA, analyzing its dependence on kinematic variables and comparing results with theoretical models to enhance understanding of proton structure.

Contribution

It provides the first detailed measurement of DVCS cross sections as functions of Q^2, W, and t, including exponential t-slope parameters, and compares these with NLO QCD predictions.

Findings

Measured DVCS cross sections across a range of Q^2, W, and t.

Derived exponential t-slope parameters indicating the t-dependence.

Observed geometric scaling behavior in the DVCS cross section.

Abstract

A measurement of elastic deeply virtual Compton scattering gamma* p -> gamma p using e-p collision data recorded with the H1 detector at HERA is presented. The analysed data sample corresponds to an integrated luminosity of 145 pb^-1. The cross section is measured as a function of the virtuality Q^2 of the exchanged photon and the centre-of-mass energy W of the gamma*p system in the kinematic domain 6.5 < Q^2 < 80 GeV^2, 30 < W < 140 GeV and |t| < 1 GeV^2, where t denotes the squared momentum transfer at the proton vertex. The cross section is determined differentially in t for different Q^2 and W values and exponential t-slope parameters are derived. The measurements are compared to a NLO QCD calculation based on generalised parton distributions. In the context of the dipole approach, the geometric scaling property of the DVCS cross section is studied for different values of t.