Two Pion Photo- and Electroproduction with CLAS

Abstract

Exclusive π+π-p photo- and electroproduction data from CLAS have considerably extended the information on the spectrum and structure of nucleon resonances. The data from the π+π-p and Nπ channels have provided results on the electrocouplings of most resonances in the mass region up to 1.8 GeV and at photon virtualities up to 5.0 GeV2. The recent CLAS data on π+π-p photoproduction have improved knowledge on the photocouplings of nucleon resonances in the mass range of 1.6 GeV < MN* < 2.0 GeV and on their decays to the πΔ and ρp final hadron states. Analyses of the combined π+π-p photo- and electroproduction data have revealed evidence for the candidate-state N’(1720)3/2+. The new results on the nucleon resonance spectrum, electroexcitation amplitudes from analysis of the CLAS π+π-p photo- and electroproduction data, and their impact on the exploration of strong QCD are presented.