Measurement of the beam asymmetry $\hat{I}\pounds$ for $\ddot{I}{€}^0$ and $\hat{I}\cdot$ photoproduction on the proton at $E_{\hat{I}}^3=9$ GeV

Abstract

We report measurements of the photon beam asymmetry $\hat{I}\pounds$ for the reactions ${\vec{\hat{I}}}^{3}p\to p\ddot{I}{€}^0$ and ${\vec{\hat{I}}}^{3}p\to p\hat{I}\cdot$ from the GlueX experiment using a 9 GeV linearly-polarized, tagged photon beam incident on a liquid hydrogen target in Jefferson Lab's Hall D. The asymmetries, measured as a function of the proton momentum transfer, possess greater precision than previous $\ddot{I}{€}^0$ measurements and are the first $\hat{I}\cdot$ measurements in this energy regime. The results are compared with theoretical predictions based on $t$-channel, quasi-particle exchange and constrain the axial-vector component of the neutral meson production mechanism in these models.

6 pages, 6 figures, Published in Physical Review C: Rapid Communication