arXiv · 1802.08642
Search for $C$ violation in the decay $\eta\rightarrow\pi^0+e^++e^-$ with WASA-at-COSY
Abstract
We report on the investigation of the rare decay $\eta\rightarrow\pi^0+\text{e}^++\text{e}^-$ 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\"ulich, Germany. In total $3\times10^7$ events of the reaction $\text{p}+\text{d}\rightarrow{^3\text{He}}+\eta$ have been recorded at an excess energy of $Q = 59.8\,\textrm{MeV}$. Based on this data set the $C$ parity violating decay $\eta\rightarrow\pi^0+\gamma^*\rightarrow\pi^0+\textrm{e}^++\textrm{e}^-$ via a single-photon intermediate state has been searched for, resulting in new upper limits of $\Gamma\left(\eta\rightarrow\pi^0+\textrm{e}^++\textrm{e}^-\right)/ \Gamma\left(\eta\rightarrow\pi^++\pi^-+\pi^0\right) < 3.28\times10^{-5}$ and $\Gamma\left(\eta\rightarrow\pi^0+\textrm{e}^++\textrm{e}^-\right)/ \Gamma\left(\eta\rightarrow\textrm{all}\right) < 7.5\times10^{-6}\ (\textrm{CL} = 90\,\%)$, respectively.
Explore related subjects
Keep this discovery
P. Adlarson, W. Augustyniak, W. Bardan, M. Bashkanov, F. S. Bergmann, M. Berłowski, A. Bondar, M. Büscher, H. Calén, I. Ciepał, H. Clement, E. Czerwiński, K. Demmich, R. Engels, A. Erven, W. Erven, W. Eyrich, P. Fedorets, K. Föhl, K. Fransson, F. Goldenbaum, A. Goswami, K. Grigoryev, C. -O. Gullström, C. Hanhart, L. Heijkenskjöld, V. Hejny, N. Hüsken, L. Jarczyk, T. Johansson, B. Kamys, G. Kemmerling, G. Khatri, A. Khoukaz, A. Khreptak, D. A. Kirillov, S. Kistryn, H. Kleines, B. Kłos, W. Krzemień, P. Kulessa, A. Kupść, A. Kuzmin, K. Lalwani, D. Lersch, B. Lorentz, A. Magiera, R. Maier, P. Marciniewski, B. Mariański, H. -P. Morsch, P. Moskal, H. Ohm, W. Parol, E. Perez del Rio, N. M. Piskunov, D. Prasuhn, D. Pszczel, K. Pysz, A. Pyszniak, J. Ritman, A. Roy, Z. Rudy, O. Rundel, S. Sawant, S. Schadmand, I. Schätti-Ozerianska, T. Sefzick, V. Serdyuk, B. Shwartz, K. Sitterberg, T. Skorodko, M. Skurzok, J. Smyrski, V. Sopov, R. Stassen, J. Stepaniak, E. Stephan, G. Sterzenbach, H. Stockhorst, H. Ströher, A. Szczurek, A. Trzciński, M. Wolke, A. Wrońska, P. Wüstner, A. Yamamoto, J. Zabierowski, M. J. Zieliński, J. Złomańczuk, P. Żuprański, M. Żurek, A. Wirzba. 2018-02-23. Search for $C$ violation in the decay $\eta\rightarrow\pi^0+e^++e^-$ with WASA-at-COSY. https://doi.org/10.1016/j.physletb.2018.07.017
Cite the original work for its findings. Save a collection to share your selection of sources.