Non-diagonal DVCS and transition GPDs: A unified framework for spinless hadron case $γ^* π\to γππ$

Sangyeong Son; Kirill M. Semenov-Tian-Shansky

doi:10.1007/JHEP01(2025)119

paper

Non-diagonal DVCS and transition GPDs: A unified framework for spinless hadron case $γ^{*} π \to γ π π$

arXiv:2410.11388 · doi:10.1007/JHEP01(2025)119

Abstract

Hadron-to-two-hadron transition generalized parton distributions (GPDs) extend the concept of hadron-to-resonance transition GPDs and provide a unified description of non-diagonal hard exclusive reactions in the generalized Bjorken limit. We present the formalism for the case of spinless hadrons addressing the non-diagonal deeply virtual Compton scattering $γ^{*} π \to γ π π$ in terms of $π \to π π$ transition GPDs, which generalize GPDs for $π \to f_{0}, ρ, f_{2}, \dots$ transitions. We work out the basic properties of $π \to π π$ transition GPDs and establish the soft pion theorems at the $2 π$ production threshold. We construct the partial wave expansion of $π \to π π$ transition GPDs in the two-pion decay angles and employ the dispersive approach to constrain $π \to π π$ transition GPDs in terms of $π π$ -scattering phases with help of the Omnès representation. We estimate the $e^{-} π^{+} \to e^{-} γ π^{+} π^{0}$ cross section in the kinematics of the JLab@12 GeV incorporating the isolated $ρ (770)$ resonance state and work out the angular distributions of the cross section, specifying the observables sensitive to the polarization states of the produced $ρ (770)$ resonance.

45 pages, 15 figures, published in Journal of High Energy Physics

Non-diagonal DVCS and transition GPDs: A unified framework for spinless hadron case γ∗π→γππ

Abstract

References in corpus (42)

Non-diagonal DVCS and transition GPDs: A unified framework for spinless hadron case $γ^{*} π \to γ π π$