Hard Exclusive Electroproduction of Two Pions off Proton and Deuteron at HERMES

TL;DR

This study investigates the angular distribution of pion pairs produced in exclusive electroproduction off protons and deuterons at HERMES, providing insights into the interference of isoscalar and isovector channels within the GPD framework.

Contribution

It presents the first analysis of the angular distribution of $\pi^+\pi^-\$ pairs in this context, highlighting the interference effects predicted by GPD models.

Findings

Angular distribution analyzed in the invariant mass range 0.3-1.5 GeV.

Results support the GPD model prediction of interference between isoscalar and isovector channels.

Provides new experimental data for understanding exclusive pion pair production.

Abstract

Exclusive electroproduction of $\pi^+\pi^-$ pairs off hydrogen and deuterium targets has been studied with the HERMES experiment. The angular distribution of the $\pi^+$ in the $\pi^+\pi^-$ rest system has been studied in the invariant mass range $0.3 < m_{\pi\pi} <1.5$ GeV. Theoretical models derived in the framework of the Generalized Parton Distributions show that this angular distribution receives only contributions from the interference between the isoscalar channel I=0 and the isovector channel I=1.