Measurement of beauty production from dimuon events at HERA
Journal of High Energy Physics 2009:2 (2009)
Abstract:
Beauty production in events containing two muons in the final state has been measured with the ZEUS detector at HERA using an integrated luminosity of 114 pb-1. A low transverse-momentum threshold for muon identification, in combination with the large rapidity coverage of the ZEUS muon system, gives access to almost the full phase space for beauty production. The total cross section for beauty production in ep collisions at (s)1/2 = 318 GeV has been measured to be σtot(ep bX) = 13.9 1.5(stat.)+4.0-4.3(syst.)nb. Differential cross sections and a measurement of b correlations are also obtained, and compared to other beauty cross-section measurements, Monte Carlo models and next-to-leading-order QCD predictions. © 2009 SISSA.Measurement of charged current deep inelastic scattering cross sections with a longitudinally polarised electron beam at HERA
European Physical Journal C 61:2 (2009) 223-235
Abstract:
Measurements of the cross sections for charged current deep inelastic scattering in e - p collisions with longitudinally polarised electron beams are presented. The measurements are based on a data sample with an integrated luminosity of 175 pb-1 collected with the ZEUS detector at HERA at a centre-of-mass energy of 318 GeV. The total cross section is given for positively and negatively polarised electron beams. The differential cross-sections d σ/dQ 2, d σ/dx and d σ/dy are presented for Q 2>200 GeV2. The double-differential cross-section d 2 σ/dxdQ 2 is presented in the kinematic range 280Production of excited charm and charm-strange mesons at HERA
European Physical Journal C 60:1 (2009) 25-45
Abstract:
The production of excited charm, D 1(2420)0 and D 2* (2460)0, and charm-strange, D s1(2536)±, mesons in ep collisions was measured with the ZEUS detector at HERA using an integrated luminosity of 126 pb -1. Masses, widths and helicity parameters were determined. The measured yields were converted to the rates of c quarks hadronising as a given excited charm meson and to the ratios of the dominant D 2* (2460)0 and D s1(2536) ± branching fractions. A search for the radially excited charm meson, D *(2640)±, was also performed. The results are compared with those measured previously and with theoretical expectations. © 2009 Springer-Verlag / Società Italiana di Fisica.Search for events with an isolated lepton and missing transverse momentum and a measurement of W production at HERA
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 672:2 (2009) 106-115
Abstract:
A search for events with an isolated high-energy lepton and large missing transverse momentum has been performed with the ZEUS detector at HERA using a total integrated luminosity of 504 pb-1. The results agree well with Standard Model predictions. The cross section for production of single W bosons in electron-proton collisions with unpolarised electrons is measured to be 0.89-0.22+0.25 (stat.) ± 0.10 (syst.) pb. © 2009 Elsevier B.V.A measurement of the Q2, W and t dependences of deeply virtual Compton scattering at HERA
Journal of High Energy Physics 2009:5 (2009)