A new search for the KL→π0νν¯ and KL→π0X0 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: 2017
Předmět:
Zdroj: Progress of Theoretical and Experimental Physics
ISSN: 2050-3911
Popis: We searched for the $CP$-violating rare decay of neutral kaon, $K_{L} \to \pi^0 \nu \overline{\nu}$, 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 $K_{L} \to \pi^{0} X^{0}$decay was also set for the first time, where $X^{0}$ is an invisible particle with a mass of 135 MeV/$c^{2}$.
Databáze: OpenAIRE