Measurement of the Beam Asymmetry $\Sigma$ in the Forward Direction for pi0 Photoproduction

TL;DR

This study measures the beam asymmetry in neutral pion photoproduction at specific angles and energies, enhancing the existing data and confirming theoretical models in the forward direction.

Contribution

It provides new beam asymmetry measurements at higher energies and very forward angles, extending and improving the existing database for this reaction.

Findings

Good agreement with SAID parameterization

Enhanced data for photon energies above 1.5 GeV

Extended measurements to very forward angles

Abstract

Photoproduction of neutral pions has been studied with the CBELSA/TAPS detector for photon energies between 0.92 and 1.68~GeV at the electron accelerator ELSA. The beam asymmetry~$\Sigma$ has been extracted for $115^\circ < \theta_{\rm c.m.} < 155^\circ$ of the $\pi^0$~meson and for $\theta_{\rm c.m.} < 60^\circ$. The new beam asymmetry data improve the world database for photon energies above 1.5~GeV and, by covering the very forward region, extend previously published data for the same reaction by our collaboration. The angular dependence of $\Sigma$ shows overall good agreement with the SAID parameterization.