Timelike form factor for the anomalous process γ^∗ π→ ππ

2025/04/29 by Miramontes, Angel S., Eichmann, Gernot, Alkofer, Reinhard · 3 citations
#FOS: Physical sciences #High Energy Physics - Experiment (hep-ex) #High Energy Physics - Phenomenology (hep-ph) #Nuclear Theory (nucl-th)

paper · doi:10.48550/arxiv.2504.20899

Abstract

The form factor F_3π(s,t,u) for the anomalous process γ^∗ π→ ππ is calculated in the isospin limit for several values of the light current-quark mass (i.e., the pion mass) using Dyson-Schwinger and Bethe-Salpeter equations. Beyond a quark interaction kernel representing gluon-mediated interactions, leading beyond-rainbow-ladder effects at low energies are incorporated by back-coupling pions as explicit degrees of freedom. Building upon an earlier calculation of the quark-photon vertex that captures the branch cut associated with the two-pion threshold and the rho meson resonance, the form factor F_3π(s,t,u) is determined for timelike Mandelstam s. In particular, predictions are made for the kinematics relevant for the Primakoff reaction studied with COMPASS/AMBER at CERN.

Cited by

• Pion physics with dressed quark-gluon vertices
• Electromagnetic properties of heavy-light mesons
• A comprehensive approach to the physics of mesons

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