Measurement of single- and double-polarization observables in the photoproduction of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msup><mml:mi>π</mml:mi><mml:mo>+</mml:mo></mml:msup><mml:msup><mml:mi>π</mml:mi><mml:mo>−</mml:mo></mml:msup></mml:mrow></mml:math> meson pairs off the proton using CLAS at Jefferson Laboratory

The photoproduction of ${\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ meson pairs off the proton has been studied in the reaction $\ensuremath{\gamma}p\ensuremath{\rightarrow}p{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ 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, ${I}^{s,c}$ and ${P}_{x,y}$, have been measured along with the beam-target double-polarization observables, ${P}_{x,y}^{s,c}$, using a transversely polarized target with center-of-mass energies ranging from 1.51 GeV up to 2.04 GeV. These data and additional $\ensuremath{\pi}\ensuremath{\pi}$ 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 ${\mathrm{\ensuremath{\Delta}}}^{*}$ resonances in the third and fourth resonance regions.

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