Pre-supernova Alert System for Super-Kamiokande
L. N. Machado, K. Abe, Y. Hayato, K. Hiraide, K. Ieki, M. Ikeda, J. Kameda, Y. Kanemura, R. Kaneshima, Y. Kashiwagi, Y. Kataoka, S. Miki, S. Mine, M. Miura, S. Moriyama, Y. Nakano, M. Nakahata, S. Nakayama, Y. Noguchi, Ken‐ichi Okamoto, K. Satô, H. Sekiya, Hayato Shiba, K. Shimizu, M. Shiozawa, Y. Sonoda, Y. Suzuki, A. Takeda, Y. Takemoto, A. Takenaka, H. Tanaka, Shin Watanabe, T. Yano, P. de Perio, K. Martens, M. R. Vagins, J. M. Bian, N. J. Griskevich, W. R. Kropp, S. Locke, M. B. Smy, H. W. Sobel, Volodymyr Takhistov, A. Yankelevich, S. Han, T. Kajita, K. Okumura, T. Tashiro, Tomoaki Tomiya, X. Wang, J. Xia, S. Yoshida, G. D. Megias, P. Fernández, L. Labarga, N. Ospina, Bryan Zaldívar, B. W. Pointon, R. Akutsu, V. Gousy-Leblanc, M. Hartz, A. Konaka, N. W. Prouse, E. Kearns, J. L. Raaf, L. Wan, T. Wester, J. Hill, J. Y. Kim, I. T. Lim, R. G. Park, B. Bodur, K. Scholberg, C. W. Walter, L. Bernard, A. Coffani, O. Drapier, S. El Hedri, A. Giampaolo, Th. A. Mueller, A. De Souza Santos, Pascal Paganini, B. Quilain, T. Ishizuka, T. Nakamura, J. S. Jang, J. G. Learned, S. Cao, K. Choi, L. H. V. Anthony, D. Martin, M. Scott, A. A. Sztuc, Y. Uchida, V. Berardi, M. G. Catanesi, E. Radicioni, N. F. Calabria, G. De Rosa, G. Collazuol
Abstract
Abstract In 2020, the Super-Kamiokande (SK) experiment moved to a new stage (SK-Gd) in which gadolinium (Gd) sulfate octahydrate was added to the water in the detector, enhancing the efficiency to detect thermal neutrons and consequently improving the sensitivity to low energy electron anti-neutrinos from inverse beta decay (IBD) interactions. SK-Gd has the potential to provide early alerts of incipient core-collapse supernovae through detection of electron anti-neutrinos from thermal and nuclear processes responsible for the cooling of massive stars before the gravitational collapse of their cores. These pre-supernova neutrinos emitted during the silicon burning phase can exceed the energy threshold for IBD reactions. We present the sensitivity of SK-Gd to pre-supernova stars and the techniques used for the development of a pre-supernova alarm based on the detection of these neutrinos in SK, as well as prospects for future SK-Gd phases with higher concentrations of Gd. For the current SK-Gd phase, high-confidence alerts for Betelgeuse could be issued up to 9 hr in advance of the core collapse itself.