학술논문
Search for the Pair Production of Dark Particles $X$ with $K_L^0 \to XX$, $X \to \gamma\gamma$
Document Type
Working Paper
Author
Lin, C.; Ahn, J. K.; Choi, J. M.; Farrington, M. S.; Gonzalez, M.; Grethen, N.; Hsiung, Y. B.; Inagaki, T.; Kamiji, I.; Kim, E. J.; Kim, J. L.; Kim, H. M.; Kawata, K.; Kitagawa, A.; Komatsubara, T. K.; Kotera, K.; Lee, S. K.; Lee, J. W.; Lim, G. Y.; Luo, Y.; Matsumura, T.; Nakagiri, K.; Nanjo, H.; Nomura, T.; Ono, K.; Redeker, J. C.; Sato, T.; Sasse, V.; Shibata, T.; Shimizu, N.; Shinkawa, T.; Shinohara, S.; Shiomi, K.; Shiraishi, R.; Suzuki, S.; Tajima, Y.; Tung, Y. -C.; Wah, Y. W.; Watanabe, H.; Wu, T.; Yamanaka, T.; Yoshida, H. Y.
Source
Subject
Language
Abstract
We present the first search for the pair production of dark particles $X$ via $K_L^0\to XX$ with $X$ decaying into two photons using the data collected by the KOTO experiment. No signal was observed in the mass range of 40 - 110 MeV/c$^2$ and 210 - 240 MeV/c$^2$. This sets upper limits on the branching fractions as $\mathcal{B}(K_L^0 \to XX)$ $<$ (1-4) $\times$ 10$^{-7}$ and $\mathcal{B}(K_L^0 \to XX)$ $<$ (1-2) $\times$ 10$^{-6}$ at the 90% confidence level for the two mass regions, respectively.