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Elastic J/Psi production at HERA |
| Reference |
C. Kiesling, presented at DIS2005, Spring 2005 |
| Document |
Conference paper
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| Figures |
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| | Tables |
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| Contact |
P. Fleischmann |
| Abstract |
Cross sections for elastic production of J/Psi mesons in photoproduction
and electroproduction are presented for photon virtualities Q2 up to
80 GeV^2. The dependence on the photon-proton centre-of-mass energy W
is analysed in the range 40 < W < 305 GeV in photoproduction and
40 < W < 160 GeV in electroproduction. The W dependence of the
cross section does not change significantly with Q2 and can be described
by models based on perturbative QCD. The differential cross section dsigma/dt
is measured in the range |t| < 1.2 GeV^2, where t is the squared
four-momentum transfer
at the proton vertex. Its dependence on W and Q2 is analysed.
Effective Pomeron trajectories are determined for
photoproduction and electroproduction, which are in agreement within
errors. An analysis of the JPsi production and decay angular distributions
yields no evidence for a violation of s-channel helicity conservation.
The ratio of the cross sections for longitudinal and transverse photons is
measured as a function of Q2 and found to be described by pQCD models. |
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