Two Pion Photo- and Electroproduction with CLAS

for the CLAS Collaboration1 - Jefferson Laboratory, 12000 Jefferson Ave., Newport News , 23606, USA

^* e-mail: mokeev@jlab.org

Published online: 22 September 2020

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 < M_N* < 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.