Measurement of D*± diffractive cross sections in photoproduction at HERA

The first measurement of the cross sections for D*±-meson diffractive photoproduction was performed with the ZEUS detector at the HERA ep collider by using an integrated luminosity of 38 pb-1. The measurement was performed for photon-proton c.m. energies in the range 130 < W < 280 GeV and photon virtualities in the region Q2 < 1 GeV2. The product D*± mesons were reconstructed for pTD* > 2 GeV and -1.5 < ηD* < 1.5 from the decay channel D*± → D0πs+ with D0 → K-π+ (+ c.c.). The diffractive component was selected for 0.001 < xP < 0.018. The measured cross section in this kinematical range is σep→e'D*Xp'diff = 0.74 ± 0.21(stat.)+0.27-0.18(syst.) ± 0.16(p.diss.) nb (ZEUS preliminary). The measured integrated and differential cross sections are compared with theoretical expectations