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Transition distribution amplitudes and hard exclusive reactions with baryon number transfer
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.