Search for resonance decays to a v̄ plus jet in e+p scattering at des y HERA
Physical Review D 63:5 (2001)
Abstract:
A study of the v̄-jet mass spectrum in e+p→v̄X events at a center-of-mass energy 300 GeV has been performed with the ZEUS detector at the HERA collider at DESY using an integrated luminosity of 47.7 pb-1. The mass spectrum is in good agreement with that expected from standard model processes over the v̄-jet mass range studied. No significant excess attributable to the decay of a narrow resonance is observed. By using both e+p→>e+X and e+p-vX data, mass-dependent limits are set on the s-channel production of scalar and vector resonant states. Couplings to first-generation quarks are considered and limits are presented as a function of the e+q and v̄q branching ratios. These limits are used to constrain the production of leptoquarks and A-parity violating squarks. © 2001 The American Physical Society.Measurement of dijet cross sections for events with a leading neutron in photoproduction at HERA
NUCLEAR PHYSICS B 596:1-2 (2001) 3-29
Measurement of exclusive ω electroproduction at HERA
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 487:3-4 (2000) 273-288
Abstract:
The exclusive electroproduction of ω mesons, ep → e ω p, has been studied in the kinematic range 3 < Q2 < 20 GeV2, 40 < W < 120 GeV and |t| < 0.6 GeV2 with the ZEUS detector at HERA using an integrated luminosity of 37.7 pb-1. The ω mesons were identified via the decay ω → π+ π- π0. The exclusive cross section in the above kinematic region is σ(ep) → e ω p = 0.108 ± 0.014 (stat.) ± 0.026(syst.) nb. The reaction ep → e φ p, φ → π+ π- π0, has also been measured. The cross sections, as well as the ratios σ γ·p → ωp/σ γ · p → p0p and σ γ · p → ωp/σγ·p → φp, are presented as a function of W and Q2. Thus, for the first time, the properties of ω electroproduction can be compared to those of p0,φ and J/ψ electroproduction at high W. (C) 2000 Elsevier Science B.V.Measurement of the proton structure function F2 at very low Q2 at HERA
Physics Letters B Elsevier 487:1-2 (2000) 53-73
Measurement of azimuthal asymmetries in deep inelastic scattering
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics 481:2-4 (2000) 199-212