1. Search for neutrinoless quadruple beta decay of 136Xe in XMASS-I
- Author
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K. Abe, K. Hiraide, K. Ichimura, N. Kato, Y. Kishimoto, K. Kobayashi, M. Kobayashi, S. Moriyama, M. Nakahata, K. Sato, H. Sekiya, T. Suzuki, A. Takeda, S. Tasaka, M. Yamashita, B.S. Yang, N.Y. Kim, Y.D. Kim, Y.H. Kim, R. Ishii, Y. Itow, K. Kanzawa, K. Masuda, K. Martens, A. Mason, Y. Suzuki, K. Miuchi, Y. Takeuchi, K.B. Lee, M.K. Lee, Y. Fukuda, H. Ogawa, K. Nishijima, K. Fushimi, B.D. Xu, and S. Nakamura
- Subjects
Neutrinoless-quadruple beta decay ,Neutrino ,Low background ,Liquid xenon ,Physics ,QC1-999 - Abstract
A search for the neutrinoless quadruple beta decay of 136Xe was conducted with the liquid-xenon detector XMASS-I using 327 kg ×800.0 days of the exposure. The pulse shape discrimination based on the scintillation decay time constant which distinguishes γ-rays including the signal and β-rays was used to enhance the search sensitivity. No significant signal excess was observed from the energy spectrum fitting with precise background evaluation, and we set a lower limit of the half life of 3.7 × 1024 years at 90% confidence level. This is the first experimental constraint of the neutrinoless quadruple beta decay of 136Xe.
- Published
- 2022
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