1. Search for C violation in the decay eta -> pi(0)e(+)e(-) with WASA-at-COSY
- Author
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Adlarson, Patrik, Collaboration, WASA-at-COSY, Augustyniak, W., Bardan, W., Bashkanov, M., Bergmann, F. S., Berlowski, M., Bondar, A., Buescher, M., Calén, Hans, Ciepal, I., Clement, H., Czerwinski, E., Demmich, K., Engels, R., Erven, A., Erven, W., Eyrich, W., Fedorets, R., Foehl, K., Fransson, Kjell, Goldenbaum, F., Goswami, A., Grigoryev, K., Gullström, Carl-Oskar, Heijkenskjöld, Lena, Hejny, V., Huesken, N., Jarczyk, L., Johansson, Tord, Kamys, B., Kemmerling, G., Khatri, G., Khoukaz, A., Khreptak, A., Kirillov, D. A., Kistryn, S., Kleines, H., Klos, B., Krzemien, W., Kulessa, R., Kupsc, Andrzej, Kuzmin, A., Lalwani, K., Lersch, D., Lorentz, B., Magiera, A., Maier, R., Marciniewski, Pawel, Marianski, B., Morsch, H. -P, Moskal, R., Ohm, H., Parol, W., del Rio, E. Perez, Piskunov, N. M., Prasuhn, D., Pszczel, Damian, Pysz, K., Pyszniak, Andzej, Ritman, J., Roy, A., Rudy, Z., Rundel, O., Sawant, S., Schadmand, S., Schatti-Ozerianska, I., Sefzick, T., Serdyuk, V., Shwartz, B., Sitterberg, K., Skorodko, T., Skurzok, M., Smyrski, J., Sopov, V., Stassen, R., Stepaniak, J., Stephan, E., Sterzenbach, G., Stockhorst, H., Stroeher, H., Szczurek, A., Trzcinski, A., Wolke, Magnus, Wronska, A., Wuestner, R., Yamamoto, A., Zabierowski, J., Zielinski, M. J., Zlomanczuk, Jozef, Zupranski, R., Zurek, M., and Wirzba, A.
- Subjects
Subatomär fysik ,Astronomi, astrofysik och kosmologi ,Subatomic Physics ,Astronomy, Astrophysics and Cosmology - Abstract
We report on the search for the rare decay eta -> pi(0)e(+)e(-) which is of interest to study C violation in the electromagnetic interaction which would indicate contributions from physics beyond the Standard Model, since the allowed decay via a two-photon intermediate state is strongly suppressed. The experiment has been performed using the WASA-at-COSY installation, located at the COSY accelerator of the Forschungszentrum Julich, Germany. In total 3 x 10(7) events of the reaction pd -> He-3 eta have been recorded at an excess energy of Q = 59.8MeV. Based on this data set the C parity violating decay eta -> pi(0)gamma* -> pi(0)e(+)e(-) via a single-photon intermediate state has been searched for, resulting in new upper limits of Gamma(eta -> pi(0)e(+) e(-))/Gamma(eta -> pi(+) pi(-) pi(0)) < 3.28 x 10(-5) and Gamma(eta -> pi(0)e(+) e(-))/Gamma(eta -> all)< 7.5 x 10(-6) (CL=90%), respectively.
- Published
- 2018