Production of vector mesons and measurement of the hadronic component of photon light-cone wave function at HERA

摘要

A detailed study of vector meson production ($\phi$ and $J/\psi$) in $e^\pmp$ collisions at HERA with the ZEUS and H1 detector has been performed. Thecross sections are measured as a function of $Q^2$, $W$ and $t$. In thiscontribution, the results are summarised, compared to theoretical calculationsand the dynamical picture emerging in perturbative QCD is highlighted. Themeasurement of the hadronic component of the photon light-cone wave function inthe exclusive production of di-pions, $ep\to e \pi^+\pi^- p$ is also reported.