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

TL;DR

This paper reports on the measurement of vector meson production and the hadronic component of the photon light-cone wave function at HERA, comparing results with theoretical models and highlighting insights from perturbative QCD.

Contribution

It provides new experimental data on vector meson production and the photon light-cone wave function, enhancing understanding of QCD dynamics in ep collisions.

Findings

Cross sections depend on Q^2, W, and t

Results agree with perturbative QCD predictions

First measurement of the hadronic component in di-pion production

Abstract

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