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Diffractive vector meson production at large momentum transfer

1995; Springer Nature; Volume: 68; Issue: 1 Linguagem: Inglês

10.1007/bf01579812

1431-5858

J. R. Forshaw, M. G. Ryskin,

Quantum Chromodynamics and Particle Interactions

The diffractive process γp→V+X (whereV is a vector meson andX results from the dissociation of the proton) is studied. In particular, we consider the region of large momentum transfer (i.e. |t| ≫Λ QCD 2 ) and large centre-of-mass (CM) energy,s. The asymptotic (s→∞,s/|t|≫1) behaviour is derived from the BFKL equation and compared to that which is obtained in the Born approximation (two-gluon exchange). We also calculate the corrections to the Born graphs by iterating the BFKL kernel numerically. Improved convergence of the BFKL series is found by summing the logarithms which occur when an exchanged gluon goes nearly on shell. Importantly, we find evidence that the asymptotic solution to the BFKL equation is inappropriate over most of the HERA range and we provide more realistic predictions for the cross section. The predicted cross section is not too small and can be measured at HERA, up to momentum transfers |t|≈10 GeV2.