Speaker
Description
The exclusive deep inelastic electroproduction of psi(2S) and J/\psi(1S)
at an ep centre-of-mass energy of 317 GeV has been studied with the ZEUS
detector at HERA in the kinematic range 2 < Q2 < 80 GeV2, 30 < W < 210 GeV
and |t| < 1 GeV2, where Q2 is the photon virtuality, W is the photon--proton
centre-of-mass energy and t is the squared four-momentum transfer at the
proton vertex. The data for 2 < Q2 < 5 GeV2 were taken in the HERA I running
period and correspond to an integrated luminosity of 114 pb-1. The data for
5 < Q2 < 80 GeV2 are from both HERA I and HERA II periods and correspond to
an integrated luminosity of 468 pb-1. The decay modes analysed were mu+ mu-
and J/psi(1S) pi+ pi- for the psi(2S) and mu+ mu- for the J/psi(1S). The
cross-section ratio sigma(psi(2S))/sigma(J/psi(1S)) has been measured as a
function of Q2, W, and t. The results are compared to predictions of
QCD-inspired models of exclusive vector-meson production.
