$\pi^+$ photoproduction on the proton for photon energies from 0.725 to 2.875 GeV

TL;DR

This study measures differential cross sections for $ ext{γ} p o n ext{π}^+$ across photon energies from 0.725 to 2.875 GeV, providing new data that refine resonance analyses and impact theoretical models.

Contribution

It provides new experimental cross section data for $ ext{γ} p o n ext{π}^+$ and updates the SAID database, leading to improved resonance coupling extractions and model predictions.

Findings

Results agree with previous data below 1 GeV

Incorporation of data alters high-energy SAID predictions

Resonance couplings are extracted and compared to prior results

Abstract

Differential cross sections for the reaction $\gamma p \to n \pi^+$ have been measured with the CEBAF Large Acceptance Spectrometer (CLAS) and a tagged photon beam with energies from 0.725 to 2.875 GeV. Where available, the results obtained here compare well with previously published results for the reaction. Agreement with the SAID and MAID analyses is found below 1 GeV. The present set of cross sections has been incorporated into the SAID database, and exploratory fits have been made up to 2.7 GeV. Resonance couplings have been extracted and compared to previous determinations. With the addition of these cross sections to the world data set, significant changes have occurred in the high-energy behavior of the SAID cross-section predictions and amplitudes.