Inelastic electron-pion scattering at FNAL (SELEX)

TL;DR

This paper reports on the analysis of inelastic electron-pion scattering data from FNAL, providing new measurements of reactions related to the pion's structure, form factors, and chiral anomaly, which were not previously measured.

Contribution

It presents the first measurements of several pion-electron scattering reactions, including the determination of the pion's generalized polarizabilities and chiral anomaly transition form factors.

Findings

Measurement of $ ho o ho e'$ transition form factor.

Determination of the $ ext{F}_{3 ext{pi}}$ chiral anomaly amplitude.

First data on pion generalized polarizabilities.

Abstract

In this report we describe the analysis status of electron-pion inelastic scattering $\pi e \to \pi' e' \gamma$ and $\pi e \to \pi' e' \pi^0$ reaction data, measured in inverse pion-electron scattering at 590 GeV/c at FNAL. The data give information on reactions that were never previously measured: (1) $\pi e \to \rho e'$ scattering for a determination of the $\rho \to \pi \gamma$ radiative width from a measurement of the transition form factor near zero momentum transfer, (2) $ \pi e \to e' \pi' \pi^0$ scattering near threshold for a determination of the chiral anomaly transition form factor and the $\gamma \to 3 \pi$ F$_{3\pi}$ chiral anomaly amplitude, and (3) $\pi e \to \pi' e' \gamma $ scattering, in which a virtual photon from the electron's Coulomb field is Compton scattered on the pion, for a determination of the never previously measured generalized pion polarizabilities.