Axial-vector transition form factors and $e^+ e^- \to f_1 \pi^+ \pi^-$

TL;DR

This paper analyzes axial-vector meson transition form factors using experimental data, including new constraints from $e^+ e^- o f_1 ho$ processes, to improve the understanding of their high-energy behavior and contributions to muon g-2.

Contribution

It provides the first unambiguous determination of the couplings for the two antisymmetric TFFs using experimental constraints and integrates these into a vector-meson-dominance framework.

Findings

Stringent high-energy constraints on TFFs derived from $e^+ e^- o f_1 ho$ data.

Unambiguous determination of antisymmetric TFF couplings.

Constructed TFFs for use in muon g-2 calculations.

Abstract

We study the transition form factors (TFFs) of axial-vector mesons in the context of currently available experimental data, including new constraints from $e^+ e^- \to f_1(1285) \pi^+ \pi^-$ that imply stringent limits on the high-energy behavior and, for the first time, allow us to provide an unambiguous determination of the couplings corresponding to the two antisymmetric TFFs. We discuss how these constraints can be implemented in a vector-meson-dominance picture, and, in combination with contributions from the light-cone expansion, construct TFFs as input for the evaluation of axial-vector contributions to hadronic light-by-light scattering in the anomalous magnetic moment of the muon.