Hard Exclusive Electroproduction of Two Pions off Proton and Deuteron at HERMES
Exclusive electroproduction of $π^+π^-$ pairs off hydrogen and deuterium targets has been studied with the HERMES experiment. The angular distribution of the $π^+$ in the $π^+π^-$ rest system has been studied in the invariant mass range $0.3 < m_{ππ} <1.5$ 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.
hep-ex↗