$T$ and $F$ asymmetries in ${\ensuremath{\pi}}^{0}$ photoproduction on the proton

$T$ and $F$ asymmetries in $π^{0}$ photoproduction on the proton

J. R. M. Annand et al. (A2 Collaboration at MAMI)

Phys. Rev. C 93, 055209 – Published 31 May 2016

Abstract

The $γ p \to π^{0} p$ reaction was studied at laboratory photon energies from 425 to 1445 MeV with a transversely polarized target and a longitudinally polarized beam. The beam-target asymmetry $F$ was measured for the first time and new high precision data for the target asymmetry $T$ were obtained. The experiment was performed at the photon tagging facility of the Mainz Microtron (MAMI) using the Crystal Ball and TAPS photon spectrometers. The polarized cross sections were expanded in terms of associated Legendre functions and compared to recent predictions from several partial-wave analyses. The impact of the new data on our understanding of the underlying partial-wave amplitudes and baryon resonance contributions is discussed.