Beam-Helicity Asymmetries in Double Pion Photoproduction off the Proton

Abstract

Beam-helicity asymmetries have been measured at the MAMI accelerator in Mainz in the three isospin channels $\vec{\gamma }p\to {\pi }^{+}{\pi }^{0}n$, $\vec{\gamma }p\to {\pi }^0{\pi }^{0}p$ and $\vec{\gamma }p\to {\pi }^{+}{\pi }^{-}p$ . The circularly polarized photons, produced from bremsstrahlung of longitudinally polarized electrons, were tagged with the Glasgow magnetic spectrometer. Charged pions and the decay photons of ${\pi }^0$ mesons were detected in a $4\pi$ electromagnetic calorimeter which combined the Crystal Ball detector with the TAPS detector. The precisely measured asymmetries are very sensitive to details of the production processes and are thus key observables in the modeling of the reaction dynamics.

accepted for publication in Phys. Rev. Lett

References in corpus (2)

• New results on the Roper resonance and the P_{11} partial wave
• Double pion photoproduction off 40Ca

Cited by in corpus (10)

• Light Baryon Spectroscopy
• Study of the gamma p --> pi0 pi0 p reaction with the Crystal Ball/TAPS at the Mainz
• Photoproduction of pi0pi0 and pi0pi+-pairs off the proton from threshold to the second resonance region
• First measurement of the circular beam asymmetry in the gamma p --> pi0 eta p reaction
• Evaluation of the polarization observables I^S and I^C in the reaction gamma p --> pi^0 eta p
• Measurement of the beam-helicity asymmetry $I^{\odot }$ in the photoproduction of ${\pi }^0{\pi }^{\pm }$-pairs off protons and off neutrons
• Photoproduction ofeta-pi pairs off nucleons and deuterons
• Polarization observables in ${\pi }^0\eta$-photoproduction on the proton
• Helicity-dependent cross sections for the photoproduction of ${\pi }^0$ pairs from nucleons
• Minimal complete sets for two pseudoscalar meson photoproduction