A new search for the $K_{L} \to ��^0 ��\overline��$ and $K_{L} \to ��^{0} X^{0}$ decays

Autor: Ahn, J. K., Baek, K. Y., Banno, S., Beckford, B., Brubaker, B., Cai, T., Campbell, M., Carruth, C., Chen, S. H., Chu, S., Comfort, J., Duh, Y. T., Furukawa, T., Haraguchi, H., Hineno, T., Hsiung, Y. B., Hutcheson, M., Inagaki, T., Isoe, M., Iwai, E., Kamibayashi, T., Kamiji, I., Kawasaki, N., Kim, E. J., Kim, Y. J., Ko, J. W., Komatsubara, T. K., Kurilin, A. S., Lee, G. H., Lee, H. S., Lee, J. W., Lee, S. K., Lim, G. Y., Lin, C., Ma, J., Maeda, Y., Masuda, T., Matsumura, T., Mcfarland, D., Micallef, J., Miyazaki, K., Morgan, K., Murayama, R., Naito, D., Nakagiri, K., Nakajima, Y., Nakaya, Y., Nanjo, H., Nomura, T., Odani, Y., Ogata, R., Okuno, H., Ota, T., Ri, Y. D., Sasaki, M., Sasao, N., Sato, K., Sato, T., Seki, S., Shimogawa, T., Shinkawa, T., Shinohara, S., Shiomi, K., Son, J. S., Stevens, J., Su, S., Sugiyama, Y., Suzuki, S., Tajima, Y., Takahashi, G., Takashima, Y., Tecchio, M., Teo, I., Togawa, M., Toyoda, T., Tung, Y. C., Usuki, T., Wah, Y. W., Watanabe, H., Whallon, N., Woo, J. K., Xu, J., Yamaga, M., Yamamoto, S., Yamanaka, T., Yamauchi, H., Yanagida, Y., Yokota, H., Yoshida, H. Y., Yoshimoto, H.
Rok vydání: 2016
Předmět:
DOI: 10.48550/arxiv.1609.03637
Popis: We searched for the $CP$-violating rare decay of neutral kaon, $K_{L} \to ��^0 ��\overline��$, in data from the first 100 hours of physics running in 2013 of the J-PARC KOTO experiment. One candidate event was observed while $0.34\pm0.16$ background events were expected. We set an upper limit of $5.1\times10^{-8}$ for the branching fraction at the 90\% confidence level (C.L.). An upper limit of $3.7\times10^{-8}$ at the 90\% C.L. for the $K_{L} \to ��^{0} X^{0}$decay was also set for the first time, where $X^{0}$ is an invisible particle with a mass of 135 MeV/$c^{2}$.
11 pages, 5 figures, to be published in PTEP
Databáze: OpenAIRE