Search for $C$ violation in the decay $��\rightarrow��^0+e^++e^-$ with WASA-at-COSY
| Autor: | Adlarson, P., Augustyniak, W., Bardan, W., Bashkanov, M., Bergmann, F. S., Ber��owski, M., Bondar, A., B��scher, M., Cal��n, H., Ciepa��, I., Clement, H., Czerwi��ski, E., Demmich, K., Engels, R., Erven, A., Erven, W., Eyrich, W., Fedorets, P., F��hl, K., Fransson, K., Goldenbaum, F., Goswami, A., Grigoryev, K., Gullstr��m, C. -O., Hanhart, C., Heijkenskj��ld, L., Hejny, V., H��sken, N., Jarczyk, L., Johansson, T., Kamys, B., Kemmerling, G., Khatri, G., Khoukaz, A., Khreptak, A., Kirillov, D. A., Kistryn, S., Kleines, H., K��os, B., Krzemie��, W., Kulessa, P., Kup����, A., Kuzmin, A., Lalwani, K., Lersch, D., Lorentz, B., Magiera, A., Maier, R., Marciniewski, P., Maria��ski, B., Morsch, H. -P., Moskal, P., Ohm, H., Parol, W., del Rio, E. Perez, Piskunov, N. M., Prasuhn, D., Pszczel, D., Pysz, K., Pyszniak, A., Ritman, J., Roy, A., Rudy, Z., Rundel, O., Sawant, S., Schadmand, S., Sch��tti-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., Str��her, H., Szczurek, A., Trzci��ski, A., Wolke, M., Wro��ska, A., W��stner, P., Yamamoto, A., Zabierowski, J., Zieli��ski, M. J., Z��oma��czuk, J., ��upra��ski, P., ��urek, M., Wirzba, A. |
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| Rok vydání: | 2018 |
| Předmět: | |
| DOI: | 10.48550/arxiv.1802.08642 |
| Popis: | We report on the investigation of the rare decay $��\rightarrow��^0+\text{e}^++\text{e}^-$ which is of interest to study both $C$ violation in the electromagnetic interaction and to search for 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 J��lich, Germany. In total $3\times10^7$ events of the reaction $\text{p}+\text{d}\rightarrow{^3\text{He}}+��$ have been recorded at an excess energy of $Q = 59.8\,\textrm{MeV}$. Based on this data set the $C$ parity violating decay $��\rightarrow��^0+��^*\rightarrow��^0+\textrm{e}^++\textrm{e}^-$ via a single-photon intermediate state has been searched for, resulting in new upper limits of $��\left(��\rightarrow��^0+\textrm{e}^++\textrm{e}^-\right)/ ��\left(��\rightarrow��^++��^-+��^0\right) < 3.28\times10^{-5}$ and $��\left(��\rightarrow��^0+\textrm{e}^++\textrm{e}^-\right)/ ��\left(��\rightarrow\textrm{all}\right) < 7.5\times10^{-6}\ (\textrm{CL} = 90\,\%)$, respectively. 7 pages, 8 figures, submitted to PLB |
| Databáze: | OpenAIRE |
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