Quasifree photoproduction of η mesons off protons and neutrons

Werthmüller, D. et al. (2014) Quasifree photoproduction of η mesons off protons and neutrons. Physical Review C, 90(1), 015205. (doi:10.1103/PhysRevC.90.015205)

Full text not currently available from Enlighten.

Publisher's URL: http://dx.doi.org/10.1103/PhysRevC.90.015205

Abstract

Differential and total cross sections for the quasifree reactions γp→ηp and γn→ηn have been determined at the MAMI-C electron accelerator by using a liquid deuterium target. Photons were produced via bremsstrahlung from the 1.5 GeV incident electron beam and energy tagged with the Glasgow photon tagger. Decay photons of the neutral decay modes η→2γ and η→3π0→6γ and coincident recoil nucleons were detected in a combined setup of the Crystal Ball and the TAPS calorimeters. The η-production cross sections were measured in coincidence with recoil protons, recoil neutrons, and in an inclusive mode without a condition on recoil nucleons, which allowed a check of the internal consistency of the data. The effects from nuclear Fermi motion were removed by a kinematic reconstruction of the final-state invariant mass and possible nuclear effects on the quasifree cross section were investigated by a comparison of free and quasifree-proton data. The results, which represent a significant improvement in statistical quality compared to previous measurements, agree with the known neutron-to-proton cross-section ratio in the peak of the S11(1535) resonance and confirm a peak in the neutron cross section, which is absent for the proton, at a center-of-mass energy W=(1670±5) MeV with an intrinsic width of Γ≈30 MeV.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:McGeorge, Dr John and Robinson, Mr Jamie and Downie, Dr Evangeline and Livingston, Dr Kenneth and MacGregor, Professor Douglas and Howdle, Mr David and Annand, Dr John and Mancell, Mr Joe and Hamilton, Dr David and Glazier, Dr Derek
Authors: Werthmüller, D., Witthauer, L., Keshelashvili, I., Aguar-Bartolomé, P., Ahrens, J., Annand, J. R. M., Arends, H. J., Bantawa, K., Beck, R., Bekrenev, V., Braghieri, A., Branford, D., Briscoe, W. J., Brudvik, J., Cherepnya, S., Costanza, S., Demissie, B., Dieterle, M., Downie, E. J., Drexler, P., Fil'kov, L. V., Fix, A., Glazier, D. I., Hamilton, D., Heid, E., Hornidge, D., Howdle, D., Huber, G. M., Jaegle, I., Jahn, O., Jude, T. C., Käser, A., Kashevarov, V. L., Kondratiev, R., Korolija, M., Kruglov, S. P., Krusche, B., Kulbardis, A., Lisin, V., Livingston, K., MacGregor, I. J. D., Maghrbi, Y., Mancell, J., Manley, D. M., Marinides, Z., Martinez, M., McGeorge, J. C., McNicoll, E. F., Metag, V., Middleton, D. G., Mushkarenkov, A., Nefkens, B. M. K., Nikolaev, A., Novotny, R., Oberle, M., Ostrick, M., Otte, P. B., Oussena, B., Pedroni, P., Pheron, F., Polonski, A., Prakhov, S. N., Robinson, J., Rosner, G., Rostomyan, T., Schumann, S., Sikora, M. H., Sober, D., Starostin, A., Supek, I., Thiel, M., Thomas, A., Unverzagt, M., and Watts, D. P.
College/School:College of Science and Engineering > School of Physics and Astronomy
Journal Name:Physical Review C
Publisher:American Physical Society
ISSN:0556-2813
ISSN (Online):1089-490X

University Staff: Request a correction | Enlighten Editors: Update this record