Double-pion electroproduction off protons in deuterium: Quasifree cross sections and final-state interactions

TL;DR

This study measures quasifree double-pion electroproduction cross sections off protons in deuterium, providing new insights into final-state interactions and comparing them with free proton data to understand nuclear effects.

Contribution

First extraction of quasifree double-pion electroproduction cross sections off protons in deuterium with detailed kinematic binning and comparison to free proton data.

Findings

Cross sections measured across a broad W and Q^2 range.

Evidence of final-state interactions affecting the cross sections.

Quantitative estimates of spectator neutron interactions.

Abstract

The single-differential and fully integrated cross sections for quasifree $\pi^{+}\pi^{-}$ electroproduction off protons bound in deuterium have been extracted for the first time. The experimental data were collected at Jefferson Laboratory with the CLAS detector. The measurements were performed in the kinematic region of the invariant mass $W$ from 1.3 to 1.825 GeV and the photon virtuality $Q^{2}$ from 0.4 to 1.0 GeV$^2$. Sufficient experimental statistics allowed for narrow binning in all kinematic variables, while maintaining a small statistical uncertainty. The extracted cross sections were compared with the corresponding cross sections off free protons, which allowed us to obtain an estimate of the contribution from events in which interactions between the final-state hadrons and the spectator neutron took place.