Model Analysis of the $ep \to ep'\pi^+\pi^-$ Electroproduction Reaction on the Proton

TL;DR

This paper analyzes CLAS data on proton electroproduction of two pions using a phenomenological model, identifying production mechanisms and extracting cross sections and amplitudes to aid future coupled-channel analyses.

Contribution

It provides a detailed phenomenological analysis of double pion electroproduction, extracting cross sections and partial wave amplitudes for the first time in this context.

Findings

Identification of production mechanisms from observables

Extraction of cross sections for isobar channels

Determination of non-resonant partial wave amplitudes

Abstract

Recent CLAS data on the $p\pi^+\pi^-$ electroproduction off protons at 1.3$<$W$<$1.57 GeV and 0.25$<$$Q^{2}$$<$0.6 GeV$^{2}$ have been analyzed using a meson-baryon phenomenological model. By fitting nine 1-fold differential cross section data for each $W$ and $Q^{2}$ bin, the charged double pion electroproduction mechanisms are identified from their manifestations in the observables. We have extracted the cross sections from amplitudes of each of the considered isobar channels as well as from their coherent sum. We also obtained non-resonant partial wave amplitudes of all contributing isobar channels which could be useful for advancing a complete coupled-channel analysis of all meson electroproduction data.