The ZEUS detector has been used to study dissociation of virtual photons in events with a leading proton, gamma* p -> X p , in e+ p collisions at HERA. The data cover photon virtualities in two ranges, 0.03 < Q2 < 0.60 GeV2 and 2 < Q2 < 100 GeV2, with MX > 1.5 GeV, where MX is the mass of the hadronic final state, X. Events were required to have a leading proton, detected in the ZEUS leading proton spectrometer, carrying at least 90% of the incoming proton energy. The cross section is presented as a function of t, the squared four-momentum transfer at the proton vertex, Phi , the azimuthal angle between the positron scattering plane and the proton scattering plane, and Q2. The data are presented in terms of the diffractive structure function, F_2D(3) . A next-to-leading-order QCD fit to the higher-Q2 data set and to previously published diffractive charm production data is presented.
Dissociation of virtual photons in events with a leading proton at HERA
CIRIO, Roberto;COSTA, Marco;FERRERO, Maria Italia;MONACO, Vincenzo;PERONI, Cristiana;SACCHI, Roberto;SOLANO, Ada Maria;
2004-01-01
Abstract
The ZEUS detector has been used to study dissociation of virtual photons in events with a leading proton, gamma* p -> X p , in e+ p collisions at HERA. The data cover photon virtualities in two ranges, 0.03 < Q2 < 0.60 GeV2 and 2 < Q2 < 100 GeV2, with MX > 1.5 GeV, where MX is the mass of the hadronic final state, X. Events were required to have a leading proton, detected in the ZEUS leading proton spectrometer, carrying at least 90% of the incoming proton energy. The cross section is presented as a function of t, the squared four-momentum transfer at the proton vertex, Phi , the azimuthal angle between the positron scattering plane and the proton scattering plane, and Q2. The data are presented in terms of the diffractive structure function, F_2D(3) . A next-to-leading-order QCD fit to the higher-Q2 data set and to previously published diffractive charm production data is presented.File | Dimensione | Formato | |
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