Pseudoscalar meson form factors and decays

TL;DR

This paper reviews recent experimental data on light pseudoscalar mesons, focusing on their contributions to muon g-2, rare decays, transition form factors, and the pion transversity form factor, highlighting theoretical modeling efforts.

Contribution

It demonstrates how the nonlocal chiral quark model describes transition form factor data and meson distribution amplitude evolution at large momentum transfer.

Findings

New BABAR data on transition form factors at high momentum transfer

Successful description of form factors using the nonlocal chiral quark model

Insights into meson distribution amplitude evolution with quark and meson masses

Abstract

In this communication we discuss few topics related with modern experimental data on the physics of light pseudoscalar mesons. It includes the contribution of the pseudoscalar mesons to the muon anomalous magnetic moment (AMM), $g-2$, the rare decays of light pseudoscalar mesons to lepton pair, the transition form factors of pseudoscalar mesons at large momentum transfer, the pion transversity form factor. Measuring the muon anomalous magnetic moment $g-2$ and the rare decays of light pseudoscalar mesons into lepton pair $P\rightarrow l^{+}l^{-} $ serve as important test of the standard model. To reduce the theoretical uncertainty in the standard model predictions the data on the transition form factors of light pseudoscalar mesons play significant role. Recently new data on behavior of these form factors at large momentum transfer was supplied by the BABAR collaboration. Within the nonlocal chiral quark model it shown how to describe these data and how the meson distribution amplitude evolves as a function of the dynamical quark masses and meson masses.