Beam-helicity asymmetries in double-pion photoproduction off the proton

D. Krambrich, F. Zehr, A. Fix, L. Roca, P. Aguar, J. Ahrens, J. R.M. Annand, H. J. Arends, R. Beck, V. Bekrenev, B. Boillat, A. Braghieri, D. Branford, W. J. Briscoe, J. Brudvik, S. Cherepnya, R. Codling, E. J. Downie, P. Dexler, D. I. GlazierP. Grabmayr, R. Gregor, E. Heid, D. Hornidge, O. Jahn, V. L. Kashevarov, A. Knezevic, R. Kondratiev, M. Korolija, M. Kotulla, B. Krusche, A. Kulbardis, M. Lang, V. Lisin, K. Livingston, S. Lugert, I. J.D. MacGregor, D. M. Manley, M. Martinez, J. C. McGeorge, D. Mekterovic, V. Metag, B. M.K. Nefkens, A. Nikolaev, P. Pedroni, F. Pheron, A. Polonski, S. N. Prakhov, J. W. Price, G. Rosner, M. Rost, T. Rostomyan, S. Schumann, D. Sober, A. Starostin, I. Supek, C. M. Tarbert, A. Thomas, M. Unverzagt, Th Walcher, D. P. Watts

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Abstract

Beam-helicity asymmetries have been measured at the MAMI accelerator in Mainz in the three isospin channels γ→p→π+π0n, γ→p→π0π0p, and γ→p→π+π-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 π0 mesons were detected in a 4π 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.

Original languageEnglish
Article number052002
JournalPhysical Review Letters
Volume103
Issue number5
DOIs
Publication statusPublished - 6 Aug 2009

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ASJC Scopus subject areas

  • Physics and Astronomy(all)

Cite this

Krambrich, D., Zehr, F., Fix, A., Roca, L., Aguar, P., Ahrens, J., Annand, J. R. M., Arends, H. J., Beck, R., Bekrenev, V., Boillat, B., Braghieri, A., Branford, D., Briscoe, W. J., Brudvik, J., Cherepnya, S., Codling, R., Downie, E. J., Dexler, P., ... Watts, D. P. (2009). Beam-helicity asymmetries in double-pion photoproduction off the proton. Physical Review Letters, 103(5), [052002]. https://doi.org/10.1103/PhysRevLett.103.052002