Measurement of single- and double-polarization observables in the photoproduction of π+π− meson pairs off the proton using CLAS at Jefferson Laboratory

The photoproduction of π+π− meson pairs off the proton has been studied in the reaction γ p→ pπ+π− using the CEBAF Large Acceptance Spectrometer (CLAS) and the frozen-spin target (FROST) in Hall B at the Thomas Jefferson National Accelerator Facility. For the first time, the beam and target asymmetries, Is,c and Px,y have been measured along with the beam-target double-polarization observables, Ps,cx,y using a transversely polarized target with center-of-mass energies ranging from 1.51 GeV up to 2.04 GeV. These data and additional ππ photoproduction observables from CLAS and experiments elsewhere were included in a partial-wave analysis within the Bonn-Gatchina framework. Significant contributions from s-channel resonance production are observed in addition to t-channel exchange processes. The data indicate significant contributions from N* and Δ* resonances in the third and fourth resonance regions.