Pre-supernova Alert System for Super-Kamiokande

Machado, L. N.; Abe, K.; Hayato, Y.; Hiraide, K.; Ieki, K.; Ikeda, M.; Kameda, J.; Kanemura, Y.; Kaneshima, R.; Kashiwagi, Y.; Kataoka, Y.; Miki, S.; Mine, S.; Miura, M.; Moriyama, S.; Nakano, Y.; Nakahata, M.; Nakayama, S.; Noguchi, Y.; Okamoto, K.; Sato, K.; Sekiya, H.; Shiba, H.; Shimizu, K.; Shiozawa, M.; Sonoda, Y.; Suzuki, Y.; Takeda, A.; Takemoto, Y.; Takenaka, A.; Tanaka, H.; Watanabe, S.; Yano, T.; De Perio, P.; Martens, K.; Vagins, M. R.; Bian, J.; Griskevich, N. J.; Kropp, W. R.; Locke, S.; Smy, M. B.; Sobel, H. W.; Takhistov, V.; Yankelevich, A.; Han, S.; Kajita, T.; Okumura, K.; Tashiro, T.; Tomiya, T.; Wang, X.; Xia, J.; Yoshida, S.; Megias, G. D.; Fernandez, P.; Labarga, L.; Ospina, N.; Zaldivar, B.; Pointon, B. W.; Akutsu, R.; Gousy-Leblanc, V.; Hartz, M.; Konaka, A.; Prouse, N. W.; Kearns, E.; Raaf, J. L.; Wan, L.; Wester, T.; Hill, J.; Kim, J. Y.; Lim, I. T.; Park, R. G.; Bodur, B.; Scholberg, K.; Walter, C. W.; Bernard, L.; Coffani, A.; Drapier, O.; El Hedri, S.; Giampaolo, A.; Mueller, T. A.; Santos, A. D.; Paganini, P.; Quilain, B.; Ishizuka, T.; Nakamura, T.; Jang, J. S.; Learned, J. G.; Cao, S.; Choi, K.; Anthony, L. H. V.; Martin, D.; Scott, M.; Sztuc, A. A.; Uchida, Y.; Berardi, V.; Catanesi, M. G.; Radicioni, E.; Calabria, N. F.; De Rosa, G.; Collazuol, G.; Iacob, F.; Lamoureux, M.; Mattiazzi, M.; Ludovici, L.; Gonin, M.; Pronost, G.; Fujisawa, C.; Maekawa, Y.; Nishimura, Y.; Sasaki, R.; Friend, M.; Hasegawa, T.; Ishida, T.; Jakkapu, M.; Kobayashi, T.; Matsubara, T.; Nakadaira, T.; Nakamura, K.; Oyama, Y.; Sakashita, K.; Sekiguchi, T.; Tsukamoto, T.; Boschi, T.; Di Lodovico, F.; Gao, J.; Goldsack, A.; Katori, T.; Migenda, J.; Taani, M.; Zsoldos, S.; Kotsar, Y.; Ozaki, H.; Suzuki, A. T.; Takeuchi, Y.; Yaamoto, S.; Bronner, C.; Feng, J.; Kikawa, T.; Mori, M.; Nakaya, T.; Wendell, R. A.; Yasutome, K.; Jenkins, S. J.; Mccauley, N.; Mehta, P.; Tsui, K. M.; Fukuda, Y.; Itow, Y.; Menjo, H.; Ninomiya, K.; Lagoda, J.; Lakshmi, S. M.; Mandal, M.; Mijakowski, P.; Prabhu, Y. S.; Zalipska, J.; Jia, M.; Jiang, J.; Jung, C. K.; Wilking, M. J.; Yanagisawa, C.; Harada, M.; Ishino, H.; Ito, S.; Kitagawa, H.; Koshio, Y.; Ma, W.; Nakanishi, F.; Sakai, S.; Barr, G.; Barrow, D.; Cook, L.; Samani, S.; Wark, D.; Nova, F.; Yang, J. Y.; Malek, M.; Mcelwee, J. M.; Stone, O.; Thiesse, M. D.; Thompson, L. F.; Okazawa, H.; Kim, S. B.; Seo, J. W.; Yu, I.; Ichikawa, A. K.; Nakamura, K. D.; Tairafune, S.; Nishijima, K.; Iwamoto, K.; Nakagiri, K.; Nakajima, Y.; Taniuchi, N.; Yokoyama, M.; Izumiyama, S.; Kuze, M.; Inomoto, M.; Ishitsuka, M.; Ito, H.; Kinoshita, T.; Matsumoto, R.; Ommura, Y.; Shigeta, N.; Shinoki, M.; Suganuma, T.; Yonenaga, M.; Martin, J. F.; Tanaka, H. A.; Towstego, T.; Chen, S.; B. D., Xu; Zhang, B.; Posiadala-Zezula, M.; Hadley, D.; Nicholson, M.; O'Flaherty, M.; Richards, B.; Ali, A.; Jamieson, B.; Marti, L.; Minamino, A.; Pintaudi, G.; Sano, S.; Suzuki, S.; Wada, K.

doi:10.3847/1538-4357/ac7f9c

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.