Measurement of isolated photon production in deep inelastic ep scattering

Abstract

Isolated photon production in deep inelastic ep scattering has been measured with the ZEUS detector at HERA using an integrated luminosity of 320 pb(-1). Measurements were made in the isolated-photon transverse-energy and pseudorapidity ranges 4 <E-T(gamma) <15 GeV and 0.7 <eta(gamma) <0.9 for exchanged photon virtualities, Q(2), in the range 10 <Q(2) <350 GeV2 and for invariant masses of the hadronic system W-X > 5 GeV. Differential cross sections are presented for inclusive isolated photon production as functions of Q(2), x, E-T(gamma) and eta(gamma). Leading-logarithm parton-shower Monte Carlo simulations and perturbative QCD predictions give a reasonable description of the data over most of the kinematic range