Experimental study of the gamma p -> eta p reaction with the Crystal Ball detector at the Mainz Microtron (MAMI-C)

Crystal Ball Collaboration MAMI, E. F. McNicoll, S. Prakhov, I. I. Strakovsky, P. Aguar-Bartolome, L. K. Akasoy, J. R. M. Annand, H. J. Arends, R. A. Arndt, Ya. I. Azimov, K. Bantawa, R. Beck, V. S. Bekrenev, H. Berghaeuser, A. Braghieri, D. Branford, W. J. Briscoe, J. Brudvik, S. Cherepnya, R. F. B. CodlingB. T. Demissie, E. J. Downie, P. Drexler, L. V. Fil'kov, A. Fix, B. Freehart, D. I. Glazier, R. Gregor, D. Hamilton, E. Heid, D. Hornidge, I. Jaegle, O. Jahn, T. C. Jude, V. L. Kashevarov, J. D. Kellie, I. Keshelashvili, R. Kondratiev, M. Korolija, M. Kotulla, A. A. Koulbardis, S. P. Kruglov, B. Krusche, V. Lisin, K. Livingston, I. J. D. MacGregor, Y. Maghrbi, D. M. Manley, Z. Marinides, M. Martinez, D. P. Watts

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The gamma p -> eta p reaction has been measured with the Crystal Ball and TAPS multiphoton spectrometers in the energy range from the production threshold of 707 MeV to 1.4 GeV (1.49 <= W <= 1.87 GeV). Bremsstrahlung photons produced by the 1.5-GeV electron beam of the Mainz Microtron MAMI-C and momentum analyzed by the Glasgow tagging spectrometer were used for the eta-meson production. Our accumulation of 3.8 x 10(6) gamma p -> eta p -> 3 pi(0) p -> 6 gamma p events allows a detailed study of the reaction dynamics. The gamma p -> eta p differential cross sections were determined for 120 energy bins and the full range of the production angles. Our data show a dip near W = 1680 MeV in the total cross section caused by a substantial dip in eta production at forward angles. The data are compared to predictions of previous SAID and MAID partial-wave analyses and to the latest SAID and MAID fits that included our data.

Original languageEnglish
Article number035208
Pages (from-to)-
Number of pages12
JournalPhysical Review C
Issue number3
Publication statusPublished - 22 Sep 2010

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