Transition distribution amplitudes and hard exclusive reactions with baryon number transfer

TL;DR

This paper reviews the concept of transition distribution amplitudes (TDAs), their properties, and their role in describing hard exclusive reactions involving baryon number transfer, highlighting experimental prospects at various facilities.

Contribution

It introduces baryon-to-meson and baryon-to-photon TDAs as a new framework extending GPDs and DAs for baryon structure analysis, and discusses experimental signals and future opportunities.

Findings

First signals observed in backward meson electroproduction at JLab

TDAs provide a complementary tool for baryon structure studies

Potential for accessing TDAs at multiple experimental facilities

Abstract

Baryon-to-meson and baryon-to-photon transition distribution amplitudes (TDAs) arise in the collinear factorized description of a class of hard exclusive reactions characterized by the exchange of a non-zero baryon number in the cross channel. These TDAs extend the concepts of generalized parton distributions (GPDs) and baryon distribution amplitudes (DAs). In this review, we discuss the general properties and physical interpretation of baryon-to-meson and baryon-to-photon TDAs. We argue that these non-perturbative objects are a convenient complementary tool to explore the structure of baryons at the partonic level. We present an overview of hard exclusive reactions admitting a description in terms of TDAs. We discuss the first signals from hard exclusive backward meson electroproduction at JLab with the 6 GeV electron beam and explore further experimental opportunities to access TDAs at JLab@12 GeV, PANDA, J-PARC and EIC.