Inclusive transverse momentum distributions of charged particles in diffractive and non–diffractive photoproduction at HERA
نویسندگان
چکیده
Inclusive transverse momentum spectra of charged particles in photoproduction events in the laboratory pseudorapidity range −1.2 < η < 1.4 have been measured up to pT = 8 GeV using the ZEUS detector. Diffractive and non–diffractive reactions have been selected with an average γp centre of mass (c.m.) energy of 〈W 〉 = 180GeV. For diffractive reactions, the pT spectra of the photon dissociation events have been measured in two intervals of the dissociated photon mass with mean values 〈MX〉 = 5 GeV and 10 GeV. The inclusive transverse momentum spectra fall exponentially in the low pT region. The non–diffractive data show a pronounced high pT tail departing from the exponential shape. The pT distributions are compared to lower energy photoproduction data and to hadron– hadron collisions at a similar c.m. energy. The data are also compared to the results of a next–to–leading order QCD calculation. DESY 95-050
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