A measurement of the Q^2, W and t dependences of deeply virtual Compton scattering at HERA

TL;DR

This paper reports measurements of deeply virtual Compton scattering at HERA, analyzing how the cross sections depend on variables Q^2, W, and t, providing new insights into the proton structure at high energies.

Contribution

It presents the first direct measurement of the differential cross section as a function of t in DVCS at HERA, expanding understanding of the process's kinematic dependencies.

Findings

Cross sections depend on Q^2 and W over a wide phase space.

First direct measurement of the t dependence of DVCS cross section.

Results contribute to understanding proton structure at high energies.

Abstract

Deeply virtual Compton scattering has been measured in e^+p collisions at HERA with the ZEUS detector using an integrated luminosity of 61.1 pb^-1. Cross sections are presented as a function of the photon virtuality, Q^2, and photon-proton centre-of-mass energy, W, for a wide region of the phase space, Q^2>~1.5 GeV^2 and 40<W<170 GeV. A subsample of events in which the scattered proton is measured in the leading proton spectrometer, corresponding to an integrated luminosity of 31.3 pb^-1, is used for the first direct measurement of the differential cross section as a function of t, where t is the square of the four-momentum transfer at the proton vertex.