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

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 ha...

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Bibliographic Details
Main Authors: Sangyeong Son, Kirill M. Semenov-Tian-Shansky
Format: Article
Language:English
Published: SpringerOpen 2025-01-01
Series:Journal of High Energy Physics
Subjects:
Online Access:https://doi.org/10.1007/JHEP01(2025)119
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Summary: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 → γππ in terms of π → ππ transition GPDs, which generalize GPDs for π → f 0, ρ, f 2, ⋯ transitions. We work out the basic properties of π → ππ transition GPDs and establish the soft pion theorems at the 2π production threshold. We construct the partial wave expansion of π → ππ transition GPDs in the two-pion decay angles and employ the dispersive approach to constrain π → ππ transition GPDs in terms of ππ-scattering phases with help of the Omnès representation. We estimate the e − π + → e − γπ + 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.
ISSN:1029-8479