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.

arXiv commentaccepted for publication in Phys. Rev. Lett

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Cited by in corpus (23)

• Baryon spectroscopy
• Progress Toward Understanding Baryon Resonances
• Phenomenological analysis of the double pion production in nucleon-nucleon collisions up to 2.2 GeV
• High statistics study of the reaction $\gamma p\to p2{\pi }^0$
• Light Baryon Spectroscopy
• Photoproduction Reactions and Non-Strange Baryon Spectroscopy
• Photoproduction of pions and properties of baryon resonances from a Bonn-Gatchina partial wave analysis
• Photoproduction of mesons off nuclei
• 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
• Photoproduction of meson pairs: First measurement of the polarization observable I^s
• First measurement of the helicity asymmetry $E$ in $\eta$ photoproduction on the proton
• Double and single pion photoproduction within a dynamical coupled-channels model
• Measurement of the beam-helicity asymmetry $I^{\odot }$ in the photoproduction of ${\pi }^0$-pairs off the proton and off the neutron
• 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
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• Polarization observables in ${\pi }^0\eta$-photoproduction on the proton
• Minimal complete sets for two pseudoscalar meson photoproduction
• Helicity-dependent cross sections for the photoproduction of ${\pi }^0$ pairs from nucleons
• Theory of two-pion photo- and electroproduction off the nucleon
• Quasi-free photoproduction of pion-pairs off protons and neutrons