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arXiv · 1007.0777

Study of the gp-->etap reaction with the Crystal Ball detector at the Mainz Microtron(MAMI-C)

E. F. McNicoll·S. Prakhov·I. I. Strakovsky·P. Aguar-Bartolomepmainz·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. Codling·B. 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·J. C. McGeorge·B. McKinnon·D. Mekterovic·V. Metag·S. Micanovic·D. Middleton·A. Mushkarenkov·B. M. K. Nefkens·A. Nikolaev·R. Novotny·M. Ostrick·P. B. Otte·B. Oussena·M. W. Paris·P. Pedroni·F. Pheron·A. Polonski·J. Robinson·G. Rosner·T. Rostomyan·S. Schumann·M. H. Sikora·D. I. Sober·A. Starostin·I. M. Suarez·I. Supek·M. Thiel·A. Thomas·L. Tiator·M. Unverzagt·D. P. Watts·D. Werthmueller·R. L. Workman·I. Zamboni·F. Zehr
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Abstract

The gp-->etap 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 gp-->etap-->3pi0p-->6gp events allows a detailed study of the reaction dynamics. The gp-->etap 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 thelatest SAID and MAID fits that have included our data.

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E. F. McNicoll, S. Prakhov, I. I. Strakovsky, P. Aguar-Bartolomepmainz, 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. Codling, B. 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, J. C. McGeorge, B. McKinnon, D. Mekterovic, V. Metag, S. Micanovic, D. Middleton, A. Mushkarenkov, B. M. K. Nefkens, A. Nikolaev, R. Novotny, M. Ostrick, P. B. Otte, B. Oussena, M. W. Paris, P. Pedroni, F. Pheron, A. Polonski, J. Robinson, G. Rosner, T. Rostomyan, S. Schumann, M. H. Sikora, D. I. Sober, A. Starostin, I. M. Suarez, I. Supek, M. Thiel, A. Thomas, L. Tiator, M. Unverzagt, D. P. Watts, D. Werthmueller, R. L. Workman, I. Zamboni, F. Zehr. 2010-07-05. Study of the gp-->etap reaction with the Crystal Ball detector at the Mainz Microtron(MAMI-C). https://doi.org/10.1103/physrevc.82.035208

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