Observation of hard scattering in photoproduction events with a large rapidity gap at HERA
ArXiv hep-ex/9501011 (1995)
Inclusive jet differential cross sections in photoproduction at HERA
Physics Letters B 342:1-4 (1995) 417-432
Abstract:
Inclusive jet differential cross sections for the reaction ep → jet + X at Q2below 4 GeV2have been measured with the ZEUS detector at HERA using an integrated luminosity of 0.55 pb-1. These cross sections are given in the kinematic region 0.2 < y < 0.85, for jet pseudorapidities in the ep-laboratory range -1 < ηjet< 2 and refer to jets at the hadron level with a cone radius of one unit in the η - θ plane. These results correspond to quasi-real photoproduction at centre-of-mass energies in the range 130-270 GeV and, approximately, for jet pseudorapidities in the interval -3 < ηjet(λp CMS) < 0. These measurements cover a new kinematic regime of the partonic structure of the photon, at typical scales up to ∼300 GeV2and photon fractional momenta down to xγ∼ 10-2. Leading logarithm parton shower Monte Carlo calculations, which include both resolved and direct processes and use the predictions of currently available parametrisations of the photon parton distributions, describe in general the shape and magnitude of the measured ηjetand Etjetdistributions. © 1995.Measurement of charged and neutral current e-p deep inelastic scattering cross sections at high Q2
Physical Review Letters 75:6 (1995) 1006-1011
Abstract:
Deep inelastic e-p scattering has been studied in both the charged current (CC) and neutral current (NC) reactions at momentum transfers squared Q2 above 400 GeV2 using the ZEUS detector at the HERA ep collider. The CC and NC total cross sections, the NC to CC cross section ratio, and the differential cross sections d/dQ2 are presented. From the Q2 dependence of the CC cross section, the mass term in the CC propagator is determined to be MW=76 16 13 GeV. © 1995 The American Physical Society.Determination of the parton distributions and structure functions of the proton from neutrino and antineutrino reactions on hydrogen and deuterium
Zeitschrift für Physik C Particles and Fields 62:4 (1994) 575-600
Abstract:
This analysis is based on data from neutrino and antineutrino scattering on hydrogen and deuterium, obtained with BEBC in the (anti) neutrino wideband beam of the CERN SPS. The parton momentum distributions in the proton and the proton structure functions are determined in the range 0.01Determination of the ratio rv =dv uv of the valence quark distributions in the proton from neutrino and antineutrino reactions on hydrogen and deuterium
Zeitschrift für Physik C Particles and Fields 62:4 (1994) 601-607