Baryon-to-Meson Transition Distribution Amplitudes: Formalism and Models

Abstract

In specific kinematics, hard exclusive amplitudes may be factorized into a short distance dominated part computable in a perturbative way on the one hand, and universal, confinement related hadronic matrix elements on the other hand. The extension of this description to processes such as backward meson electroproduction and forward meson production in antiproton-nucleon scattering leads to define new hadronic matrix elements of three quark operators on the light cone, the nucleon-to-meson transition distribution amplitudes, which shed a new light on the nucleon structure.

Backward charmonium production in πN collisions

“…The extension of the collinear factorization approach to other processes such as backward virtual Compton scattering and backward meson electroproduction, has been advocated [5,6,7] although the corresponding factorization theorems have not yet been rigorously proven. This leads to the definition of new hadronic matrix elements of three quark operators on the light cone, the nucleon-to-meson transition distribution amplitudes (TDAs) [8]. To motivate the validity of such a factorization regime, one requires the existence of a large scale Q, which may be taken as the virtuality of the photon quantifying the electromagnetic probe or the mass of a heavy quark in the case of heavy quarkonium production.…”

“…This leads to the definition of new hadronic matrix elements of three quark operators on the light cone, the nucleon-to-meson transition distribution amplitudes (TDAs) [8]. To motivate the validity of such a factorization regime, one requires the existence of a large scale Q, which may be taken as the virtuality of the photon quantifying the electromagnetic probe or the mass of a heavy quark in the case of heavy quarkonium production.…”