Measurement of deeply virtual Compton scattering at HERA

Abstract

Abstract.

A measurement is presented of elastic deeply virtual Compton scattering \(\gamma^* p \rightarrow {\ensuremath{\gamma}} p\) made using e ⁺ p collision data corresponding to a luminosity of 46.5 pb^-1, taken with the H1 detector at HERA. The cross section is measured as a function of the photon virtuality, Q ², the invariant mass of the p system, W, and for the first time, differentially in the squared momentum transfer at the proton vertex, t, in the kinematic range \(2 < Q^{ 2} < 80 {\rm GeV}^2\), \(30 < W < 140 {\rm GeV}\) and \(\vert t\vert < 1 {\rm GeV}^2\). QCD based calculations at next-to-leading order using generalized parton distributions can describe the data, as can colour dipole model predictions.