Beam asymmetry for pi+ and pi0 photoproduction on the proton for photon energies from 1.102 to 1.862 GeV

TL;DR

This paper reports precise measurements of beam asymmetries in pi+ and pi0 photoproduction on protons over a specific energy range, providing data that favor certain scattering analyses and influence resonance property fits.

Contribution

It introduces a Fourier moment technique for extracting beam asymmetries and provides higher precision data that refine existing scattering analyses.

Findings

Data favor SAID and Bonn-Gatchina analyses over Mainz MAID.

Significant changes in resonance properties after incorporating new data.

Enhanced energy resolution improves understanding of nucleon resonances.

Abstract

Beam asymmetries for the reactions gamma p -> p pi0 and gamma p -> n pi+ have been measured with the CEBAF Large Acceptance Spectrometer (CLAS) and a tagged, linearly polarized photon beam with energies from 1.102 to 1.862 GeV. A Fourier moment technique for extracting beam asymmetries from experimental data is described. The results reported here possess greater precision and finer energy resolution than previous measurements. Our data for both pion reactions appear to favor the SAID and Bonn-Gatchina scattering analyses over the older Mainz MAID predictions. After incorporating the present set of beam asymmetries into the world database, exploratory fits made with the SAID analysis indicate that the largest changes from previous fits are for properties of the Delta(1700) 3/2- and Delta(1905) 5/2+ states.