1. Search for the Pair Production of Dark Particles $X$ with $K_L^0 \to XX$, $X \to \gamma\gamma$
- Author
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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., and Yoshida, H. Y.
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High Energy Physics - Experiment - 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.
- Published
- 2022
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