Exclusive electroproduction of rhoT meson with twist three accuracy

TL;DR

This paper advances the understanding of QCD factorization by calculating the impact factor for the exclusive electroproduction of transversely polarized rho mesons, including twist 3 contributions, within the kt-factorization framework.

Contribution

It provides the first calculation of the gamma* -> rhoT impact factor at twist 3, incorporating quark-antiquark and quark-antiquark-gluon correlators with gauge invariance.

Findings

Impact factor computed with twist 3 accuracy.

Gauge invariance achieved via QCD equations of motion.

Foundation for extending factorization proofs to transversely polarized mesons.

Abstract

Exclusive electroproduction of vector mesons is a crucial way to probe QCD factorization properties. Such a factorization is up to now only proven, at the twist 2 level, for a longitudinaly polarized meson. It is crucial to extend our understanding to the case of transversely polarized vector mesons. As a first step in this direction, we evaluate the impact factor of the transition gamma* -> rhoT, which is the relevant part of the amplitude within the kt-factorization approach valid at large energies, taking into account the twist 3 contributions, coming both from quark antiquark and from quark antiquark gluon correlators. We show that a gauge invariant expression is obtained with the help of QCD equations of motion.