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Photoproduction of $\pi^0\pi^{\pm}$-pairs from quasifree nucleons bound inthe deuteron has been investigated to study the helicity dependence of thisreaction. Measurements with a liquid deuterium target were used to extract theunpolarized cross sections for reactions on protons and neutrons. A deuterated,longitudinally polarized solid-butanol target, together with a circularlypolarized photon beam, determined the double polarization observable $E$. Fromthese results the spin-dependent cross sections $\sigma_{1/2}$ and$\sigma_{3/2}$, corresponding to the anti-parallel and parallel spinconfigurations of the beam photon and target nucleon, have been derived. Themeasurements were performed at the Mainz MAMI accelerator with tagged,circularly-polarized photon beams produced via bremsstrahlung fromlongitudinally polarized electron beams. The reaction products were detectedwith an almost $4\pi$ solid-angle covering calorimeter composed of the CrystalBall and TAPS detectors, supplemented by plastic scintillation detectors forcharged particle identification. The results are sensitive to sequential decaysof nucleon resonances via intermediate states and also to the decay of nucleonresonances by emission of charged $\rho$ mesons, and are compared to recentmodel results.

Helicity dependent cross sections for the photoproduction of $\pi^0\pi^{\pm}$ pairs from quasi-free nucleons