Measurement of the photon-proton total cross section at a center-of-mass energy of 209 GeV at HERA

The photon-proton total cross section has been measured in the process e(+)p --> e(+)gammap --> e(+)X with the ZEUS detector at HERA. Events were collected with photon virtuality Q(2) < 0.02 GeV2 and average gammap center-of-mass energy W-gammap = 209 GeV in a dedicated run, designed to control systematic effects, with an integrated luminosity of 49 nb(-1). The measured total cross section is sigma(tot)(gammap) = 174 +/- 1 (stat.) +/- 13 (syst.) mub. The energy dependence of the cross section is compatible with parameterizations of high-energy p (p) over bar and p data. (C) 2002 Elsevier Science B.V. All rights reserved.