Author: "Xu, B. D." - Searchworks@Jio Institute Digital Library Search Results

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240 results on '"Xu, B. D."'

1. Search for proton decay via $p\rightarrow{e^+\eta}$ and $p\rightarrow{\mu^+\eta}$ with a 0.37 Mton-year exposure of Super-Kamiokande

Author: Collaboration, Super-Kamiokande, Taniuchi, N., Abe, K., Abe, S., Asaoka, Y., Bronner, C., Harada, M., Hayato, Y., Hiraide, K., Hosokawa, K., Ieki, K., Ikeda, M., Kameda, J., Kanemura, Y., Kaneshima, R., Kashiwagi, Y., Kataoka, Y., Miki, S., Mine, S., Miura, M., Moriyama, S., Nakahata, M., Nakayama, S., Noguchi, Y., Pronost, G., 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., Kajita, T., Okumura, K., Tashiro, T., Tomiya, T., Wang, X., Yoshida, S., Megias, G. D., Fernandez, P., Labarga, L., Ospina, N., Zaldivar, B., Pointon, B. W., Kearns, E., Mirabito, J., Raaf, J. L., Wan, L., Wester, T., Bian, J., Griskevich, N. J., Kropp, W. R., Locke, S., Smy, M. B., Sobel, H. W., Takhistov, V., Yankelevich, A., Hill, J., Jang, M. C., Kim, J. Y., Lee, S. H., Lim, I. T., Moon, D. H., Park, R. G., Yang, B. S., Bodur, B., Scholberg, K., Walter, C. W., Beauchêne, A., Bernard, L., Coffani, A., Drapier, O., Hedri, S. El, Giampaolo, A., Mueller, Th. A., Santos, A. D., Paganini, P., Rogly, R., Nakamura, T., Jang, J. S., Machado, L. N., Learned, J. G., Choi, K., Iovine, N., Cao, S., Anthony, L. H. V., Martin, D., Prouse, N. W., Scott, M., Sztuc, A. A., Uchida, Y., Berardi, V., Calabria, N. F., Catanesi, M. G., Radicioni, E., Langella, A., De Rosa, G., Collazuol, G., Feltre, M., Iacob, F., Lamoureux, M., Mattiazzi, M., Ludovici, L., Gonin, M., Périssé, L., Quilain, B., Fujisawa, C., Horiuchi, S., Kobayashi, M., Liu, Y. M., Maekawa, Y., Nishimura, Y., Okazaki, R., Akutsu, R., Friend, M., Hasegawa, T., Ishida, T., Kobayashi, T., Jakkapu, M., Matsubara, T., Nakadaira, T., Nakamura, K., Oyama, Y., Yrey, A. Portocarrero, Sakashita, K., Sekiguchi, T., Tsukamoto, T., Bhuiyan, N., Boschi, T., Burton, G. T., Di Lodovico, F., Gao, J., Goldsack, A., Katori, T., Migenda, J., Ramsden, R. M., Taani, M., Xie, Z., Zsoldos, S., Kotsar, Y., Ozaki, H., Suzuki, A. T., Takagi, Y., Takeuchi, Y., Yamamoto, S., Zhong, H., Feng, J., Feng, L., Han, S., Hu, J. R., Hu, Z., Kawaue, M., Kikawa, T., Mori, M., Nakaya, T., Wendell, R. A., Yasutome, K., Jenkins, S. J., McCauley, N., Mehta, P., Tarrant, A., Wilking, M. J., Fukuda, Y., Itow, Y., Menjo, H., Ninomiya, K., Yoshioka, Y., Lagoda, J., Mandal, M., Mijakowski, P., Prabhu, Y. S., Zalipska, J., Jia, M., Jiang, J., Jung, C. K., Shi, W., Yanagisawa, C., Hino, Y., Ishino, H., Ito, S., Kitagawa, H., Koshio, Y., Ma, W., Nakanishi, F., Sakai, S., Tada, T., Tano, T., Ishizuka, T., Barr, G., Barrow, D., Cook, L., Samani, S., Wark, D., Holin, A., Nova, F., Jung, S., Yang, J. Y., Yoo, J., Fannon, J. E. P., Kneale, L., Malek, M., McElwee, J. M., Stone, O., Stowell, P., Thiesse, M. D., Thompson, L. F., Wilson, S. T., Okazawa, H., Lakshmi, S. M., Kim, S. B., Kwon, E., Lee, M. W., Seo, J. W., Yu, I., Ichikawa, A. K., Nakamura, K. D., Tairafune, S., Nishijima, K., Koshiba, M., Eguchi, A., Goto, S., Iwamoto, K., Mizuno, Y., Muro, T., Nakagiri, K., Nakajima, Y., Shima, S., Watanabe, E., Yokoyama, M., de Perio, P., Fujita, S., Jesús-Valls, C., Martens, K., Marti, Ll., Tsui, K. M., Vagins, M. R., Xia, J., Izumiyama, S., Kuze, M., Matsumoto, R., Terada, K., Asaka, R., Inomoto, M., Ishitsuka, M., Ito, H., Kinoshita, T., Ommura, Y., Shigeta, N., Shinoki, M., Suganuma, T., Yamauchi, K., Yoshida, T., Nakano, Y., Martin, J. F., Tanaka, H. A., Towstego, T., Gaur, R., Gousy-Leblanc, V., Hartz, M., Konaka, A., Li, X., Chen, S., Wu, Y., Xu, B. D., Zhang, A. Q., Zhang, B., Posiadala-Zezula, M., Boyd, S. B., Edwards, R., Hadley, D., Nicholson, M., O'Flaherty, M., Richards, B., Ali, A., Jamieson, B., Amanai, S., Minamino, A., Pintaudi, G., Sano, S., Sasaki, R., Shibayama, R., Shimamura, R., Suzuki, S., and Wada, K.
Subjects: High Energy Physics - Experiment
Abstract: A search for proton decay into $e^+/\mu^+$ and a $\eta$ meson has been performed using data from a 0.373 Mton$\cdot$year exposure (6050.3 live days) of Super-Kamiokande. Compared to previous searches this work introduces an improved model of the intranuclear $\eta$ interaction cross section, resulting in a factor of two reduction in uncertainties from this source and $\sim$10\% increase in signal efficiency. No significant data excess was found above the expected number of atmospheric neutrino background events resulting in no indication of proton decay into either mode. Lower limits on the proton partial lifetime of $1.4\times\mathrm{10^{34}~years}$ for $p\rightarrow e^+\eta$ and $7.3\times\mathrm{10^{33}~years}$ for $p\rightarrow \mu^+\eta$ at the 90$\%$ C.L. were set. These limits are around 1.5 times longer than our previous study and are the most stringent to date.
Published: 2024

2. First joint oscillation analysis of Super-Kamiokande atmospheric and T2K accelerator neutrino data

Author: Super-Kamiokande, collaborations, T2K, Abe, S., Abe, K., Akhlaq, N., Akutsu, R., Alarakia-Charles, H., Ali, A., Hakim, Y. I. Alj, Monsalve, S. Alonso, Amanai, S., Andreopoulos, C., Anthony, L. H. V., Antonova, M., Aoki, S., Apte, K. A., Arai, T., Arihara, T., Arimoto, S., Asada, Y., Asaka, R., Ashida, Y., Atkin, E. T., Babu, N., Barbi, M., Barker, G. J., Barr, G., Barrow, D., Bates, P., Batkiewicz-Kwasniak, M., Beauchêne, A., Berardi, V., Berns, L., Bhadra, S., Bhuiyan, N., Bian, J., Blanchet, A., Blondel, A., Bodur, B., Bolognesi, S., Bordoni, S., Boyd, S. B., Bravar, A., Bronner, C., Bubak, A., Avanzini, M. Buizza, Burton, G. T., Caballero, J. A., Calabria, N. F., Cao, S., Carabadjac, D., Carter, A. J., Cartwright, S. L., Casado, M. P., Catanesi, M. G., Cervera, A., Chakrani, J., Chalumeau, A., Chen, S., Cherdack, D., Choi, K., Chong, P. S., Chvirova, A., Cicerchia, M., Coleman, J., Collazuol, G., Cook, L., Cormier, F., Cudd, A., Dalmazzone, C., Daret, T., Dasgupta, P., Davis, C., Davydov, Yu. I., De Roeck, A., De Rosa, G., Dealtry, T., Delogu, C. C., Densham, C., Dergacheva, A., Dharmapal, R., Di Lodovico, F., Lopez, G. Diaz, Dolan, S., Douqa, D., Doyle, T. A., Drapier, O., Duffy, K. E., Dumarchez, J., Dunne, P., Dygnarowicz, K., D'ago, D., Edwards, R., Eguchi, A., Elias, J., Emery-Schrenk, S., Erofeev, G., Ershova, A., Eurin, G., Fannon, J. E. P., Fedorova, D., Fedotov, S., Feltre, M., Feng, J., Feng, L., Ferlewicz, D., Fernandez, P., Finch, A. J., Aguirre, G. A. Fiorentini, Fiorillo, G., Fitton, M. D., Patiño, J. M. Franco, Friend, M., Fujii, Y., Fujisawa, C., Fujita, S., Fukuda, Y., Furui, Y., Gao, J., Gaur, R., Giampaolo, A., Giannessi, L., Giganti, C., Glagolev, V., Goldsack, A., Gonin, M., Rosa, J. González, Goodman, E. A. G., Gorin, A., Gorshanov, K., Gousy-Leblanc, V., Grassi, M., Griskevich, N. J., Guigue, M., Hadley, D., Haigh, J. T., Han, S., Harada, M., Harris, D. A., Hartz, M., Hasegawa, T., Hassani, S., Hastings, N. C., Hayato, Y., Heitkamp, I., Henaff, D., Hill, J., Hino, Y., Hiraide, K., Hogan, M., Holeczek, J., Holin, A., Holvey, T., Van, N. T. Hong, Honjo, T., Horiuchi, S., Hosokawa, K., Hu, Z., Hu, J., Iacob, F., Ichikawa, A. K., Ieki, K., Ikeda, M., Iovine, N., Ishida, T., Ishino, H., Ishitsuka, M., Ishizuka, T., Ito, H., Itow, Y., Izmaylov, A., Izumiyama, S., Jakkapu, M., Jamieson, B., Jang, M. C., Jang, J. S., Jenkins, S. J., Jesús-Valls, C., Ji, J. Y., Jia, M., Jiang, J., Jonsson, P., Joshi, S., Jung, C. K., Jung, S., Kabirnezhad, M., Kaboth, A. C., Kajita, T., Kakuno, H., Kameda, J., Kanemura, Y., Kaneshima, R., Karpova, S., Kasetti, S. P., Kashiwagi, Y., Kasturi, V. S., Kataoka, Y., Katori, T., Kawamura, Y., Kawaue, M., Kearns, E., Khabibullin, M., Khotjantsev, A., Kikawa, T., Kim, S. B., King, S., Kiseeva, V., Kisiel, J., Kneale, L., Kobayashi, H., Kobayashi, T., Kobayashi, M., Koch, L., Kodama, S., Kolupanova, M., Konaka, A., Kormos, L. L., Koshio, Y., Koto, T., Kowalik, K., Kudenko, Y., Kudo, Y., Kuribayashi, S., Kurjata, R., Kurochka, V., Kutter, T., Kuze, M., Kwon, E., La Commara, M., Labarga, L., Lachat, M., Lachner, K., Lagoda, J., Lakshmi, S. M., LamersJames, M., Langella, A., Laporte, J. -F., Last, D., Latham, N., Laveder, M., Lavitola, L., Lawe, M., Learned, J. G., Lee, Y., Lee, S. H., Silverio, D. Leon, Levorato, S., Lewis, S., Li, X., Li, W., Lin, C., Litchfield, R. P., Liu, S. L., Liu, Y. M., Long, K. R., Longhin, A., Moreno, A. Lopez, Lu, X., Ludovici, L., Lux, T., Machado, L. N., Maekawa, Y., Magaletti, L., Mahn, K., Mahtani, K. K., Malek, M., Mandal, M., Manly, S., Marino, A. D., Martens, K., Marti, Ll., Martin, D. G. R., Martin, J. F., Martin, D., Martini, M., Maruyama, T., Matsubara, T., Matsumoto, R., Mattiazzi, M., Matveev, V., Mauger, C., Mavrokoridis, K., Mazzucato, E., McCauley, N., McElwee, J. M., McFarland, K. S., McGrew, C., McKean, J., Mefodiev, A., Megias, G. D., Mehta, P., Mellet, L., Menjo, H., Metelko, C., Mezzetto, M., Migenda, J., Mijakowski, P., Miki, S., Miller, E., Minamino, A., Mine, S., Mineev, O., Mirabito, J., Miura, M., Bueno, L. Molina, Moon, D. H., Mori, M., Moriyama, S., Morrison, P., Muñoz, A., Mueller, Th. A., Munford, D., Munteanu, L., Nagai, Y., Nagai, K., Nakadaira, T., Nakagiri, K., Nakahata, M., Nakajima, Y., Nakamura, A., Nakamura, K., Nakamura, K. D., Nakamura, T., Nakanishi, F., Nakano, Y., Nakaya, T., Nakayama, S., Nakayoshi, K., Naseby, C. E. R., Ngoc, T. V., Nguyen, V. Q., Nguyen, D. T., Nicholson, M., Niewczas, K., Ninomiya, K., Nishijima, K., Nishimori, S., Nishimura, Y., Noguchi, Y., Nosek, T., Nova, F., Novella, P., Nugent, J. C., Odagawa, T., Okazaki, R., Okazawa, H., Okinaga, W., Okumura, K., Okusawa, T., Ommura, Y., Onda, N., Ospina, N., Osu, L., Oyama, Y., O'Flaherty, M., O'Keeffe, H. M., O'Sullivan, L., Périssé, L., Paganini, P., Palladino, V., Paolone, V., Pari, M., Park, R. G., Parlone, J., Pasternak, J., Payne, D., Penn, G. C., de Perio, P., Pershey, D., Pfaff, M., Pickering, L., Pintaudi, G., Pistillo, C., Pointon, B. W., Popov, B., Yrey, A. Portocarrero, Porwit, K., Posiadala-Zezula, M., Prabhu, Y. S., Prasad, H., Pronost, G., Prouse, N. W., Pupilli, F., Quilain, B., Quyen, P. T., Raaf, J. L., Radermacher, T., Radicioni, E., Radics, B., Ramirez, M. A., Ramsden, R. M., Ratoff, P. N., Reh, M., Riccio, C., Richards, B., Rogly, R., Rondio, E., Roth, S., Roy, N., Rubbia, A., Russo, L., Rychter, A., Saenz, W., Sakai, S., Sakashita, K., Samani, S., Santos, A. D., Sato, Y., Sato, K., Schefke, T., Schloesser, C. M., Scholberg, K., Scott, M., Seiya, Y., Sekiguchi, T., Sekiya, H., Seo, J. W., Sgalaberna, D., Shaikhiev, A., Shi, W., Shiba, H., Shibayama, R., Shigeta, N., Shima, S., Shimamura, R., Shimizu, K., Shinoki, M., Shiozawa, M., Shiraishi, Y., Shvartsman, A., Skrobova, N., Skwarczynski, K., Smy, M. B., Smyczek, D., Sobczyk, J. T., Sobel, H. W., Soler, F. J. P., Sonoda, Y., Speers, A. J., Spina, R., Stroke, Y., Suslov, I. A., Suvorov, S., Suzuki, S., Suzuki, A., Suzuki, S. Y., Suzuki, Y., Sánchez, F., Tada, T., Tada, M., Tairafune, S., Takagi, Y., Takeda, A., Takemoto, Y., Takeuchi, Y., Takhistov, V., Takifuji, K., Tanaka, H., Tanaka, H. K., Tanigawa, H., Taniuchi, N., Tano, T., Tarrant, A., Tashiro, T., Teklu, A., Terada, K., Tereshchenko, V. V., Thamm, N., Thiesse, M. D., Thompson, L. F., Toki, W., Tomiya, T., Touramanis, C., Tsui, K. M., Tsukamoto, T., Tzanov, M., Uchida, Y., Vagins, M. R., Vargas, D., Varghese, M., Vasseur, G., Villa, E., Vinning, W. G. S., Virginet, U., Vladisavljevic, T., Wachala, T., Wakabayashi, D., Wallace, H. T., Walsh, J. G., Walter, C. W., Wan, L., Wang, X., Wang, Y., Wark, D., Wascko, M. O., Watanabe, E., Weber, A., Wendell, R. A., Wester, T., Wilking, M. J., Wilkinson, C., Wilson, S. T., Wilson, J. R., Wood, K., Wret, C., Wu, Y., Xia, J., Xie, Z., Xu, B. D., Xu, Y. -H., Yamamoto, K., Yamamoto, T., Yamauchi, K., Yanagisawa, C., Yang, G., Yang, B. S., Yang, J. Y., Yankelevich, A., Yano, T., Yasutome, K., Yershov, N., Yevarouskaya, U., Yokoyama, M., Yoo, J., Yoshida, T., Yoshida, S., Yoshimoto, Y., Yoshimura, N., Yoshioka, Y., Yu, M., Yu, I., Zaki, R., Zaldivar, B., Zalewska, A., Zalipska, J., Zaremba, K., Zarnecki, G., Zhang, J., Zhang, A. Q., Zhang, B., Zhao, X. Y., Zhong, H., Zhu, T., Ziembicki, M., Zimmerman, E. D., Zito, M., and Zsoldos, S.
Subjects: High Energy Physics - Experiment
Abstract: The Super-Kamiokande and T2K collaborations present a joint measurement of neutrino oscillation parameters from their atmospheric and beam neutrino data. It uses a common interaction model for events overlapping in neutrino energy and correlated detector systematic uncertainties between the two datasets, which are found to be compatible. Using 3244.4 days of atmospheric data and a beam exposure of $19.7(16.3) \times 10^{20}$ protons on target in (anti)neutrino mode, the analysis finds a 1.9$\sigma$ exclusion of CP-conservation (defined as $J_{CP}=0$) and a preference for the normal mass ordering., Comment: 12 pages, 4 figures
Published: 2024

3. Development of a data overflow protection system for Super-Kamiokande to maximize data from nearby supernovae

Author: Mori, M., Abe, K., Hayato, Y., Hiraide, K., Hosokawa, 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., Han, S., Kajita, T., Okumura, K., Tashiro, T., Tomiya, T., Wang, X., Yoshida, S., Megias, G. D., Fernandez, P., Labarga, L., Ospina, N., Zaldivar, B., Pointon, B. W., Kearns, E., Raaf, J. L., Wan, L., Wester, T., Bian, J., Griskevich, N. J., Locke, S., Smy, M. B., Sobel, H. W., Takhistov, V., Yankelevich, A., Hill, J., Jang, M. C., Lee, S. H., Moon, D. H., Park, R. G., Bodur, B., Scholberg, K., Walter, C. W., Beauchene, A., Drapier, O., Giampaolo, A., Mueller, Th. A., Santos, A. D., Paganini, P., Quilain, B., Rogly, R., Ishizuka, T., Nakamura, T., Jang, J. S., Learned, J. G., Choi, K., Iovine, N., Cao, S., Anthony, L. H. V., Martin, D., Scott, M., Sztuc, A. A., Uchida, Y., Berardi, V., Catanesi, M. G., Radicioni, E., Calabria, N. F., Langella, A., Machado, L. N., De Rosa, G., Collazuol, G., Iacob, F., Lamoureux, M., Mattiazzi, M., Ludovici, L., Gonin, M., Perisse, L., Pronost, G., Fujisawa, C., Maekawa, Y., Nishimura, Y., Okazaki, R., Akutsu, R., Friend, M., Hasegawa, T., Ishida, T., Kobayashi, T., Jakkapu, M., Matsubara, T., Nakadaira, T., Nakamura, K., Oyama, Y., Sakashita, K., Sekiguchi, T., Tsukamoto, T., Bhuiyan, N., Burton, G. T., Edwards, R., Di Lodovico, F., Gao, J., Goldsack, A., Katori, T., Migenda, J., Ramsden, R. M., Xie, Z., Zsoldos, S., Kotsar, Y., Ozaki, H., Suzuki, A. T., Takagi, Y., Takeuchi, Y., Zhong, H., Bronner, C., Feng, J., Hu, J. R., Hu, Z., Kawaune, M., Kikawa, T., LiCheng, F., Nakaya, T., Wendell, R. A., Yasutome, K., Jenkins, S. J., McCauley, N., Mehta, P., Tarant, A., Fukuda, Y., Itow, Y., Menjo, H., Ninomiya, K., Yoshioka, Y., Lagoda, J., Lakshmi, S. M., Mandal, M., Mijakowski, P., Prabhu, Y. S., Zalipska, J., Jia, M., Jiang, J., Jung, C. K., Shi, W., Wilking, M. J., Yanagisawa, C., Harada, M., Hino, Y., Ishino, H., Kitagawa, H., Koshio, Y., Nakanishi, F., Sakai, S., Tada, T., Tano, T., Barr, G., Barrow, D., Cook, L., Samani, S., Wark, D., Holin, A., Nova, F., Jung, S., Yang, B. S., Yang, J. Y., Yoo, J., Fannon, J. E. P., Kneale, L., Malek, M., McElwee, J. M., Thiesse, M. D., Thompson, L. F., Wilson, S., Okazawa, H., Kim, S. B., Kwon, E., Seo, J. W., Yu, I., Ichikawa, A. K., Nakamura, K. D., Tairafune, S., Nishijima, K., Eguchi, A., Nakagiri, K., Nakajima, Y., Shima, S., Taniuchi, N., Watanabe, E., Yokoyama, M., de Perio, P., Fujita, S., Martens, K., Tsui, K. M., Vagins, M. R., Valls, C. J., Xia, J., Kuze, M., Izumiyama, S., Ishitsuka, M., Ito, H., Kinoshita, T., Matsumoto, R., Ommura, Y., Shigeta, N., Shinoki, M., Suganuma, T., Yamauchi, K., Yoshida, T., Martin, J. F., Tanaka, H. A., Towstego, T., Gaur, R., Gousy-Leblanc, V., Hartz, M., Konaka, A., Li, X., Prouse, N. W., Chen, S., Xu, B. D., Zhang, B., Posiadala-Zezula, M., Boyd, S. B., Hadley, D., Nicholson, M., Flaherty, M. O', Richards, B., Ali, A., Jamieson, B., Amanai, S., Marti, Ll., Minamino, A., Pintaudi, G., Sano, S., Suzuki, S., and Wada, K.
Subjects: Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Solar and Stellar Astrophysics, High Energy Physics - Experiment
Abstract: Neutrinos from very nearby supernovae, such as Betelgeuse, are expected to generate more than ten million events over 10\,s in Super-Kamokande (SK). At such large event rates, the buffers of the SK analog-to-digital conversion board (QBEE) will overflow, causing random loss of data that is critical for understanding the dynamics of the supernova explosion mechanism. In order to solve this problem, two new DAQ modules were developed to aid in the observation of very nearby supernovae. The first of these, the SN module, is designed to save only the number of hit PMTs during a supernova burst and the second, the Veto module, prescales the high rate neutrino events to prevent the QBEE from overflowing based on information from the SN module. In the event of a very nearby supernova, these modules allow SK to reconstruct the time evolution of the neutrino event rate from beginning to end using both QBEE and SN module data. This paper presents the development and testing of these modules together with an analysis of supernova-like data generated with a flashing laser diode. We demonstrate that the Veto module successfully prevents DAQ overflows for Betelgeuse-like supernovae as well as the long-term stability of the new modules. During normal running the Veto module is found to issue DAQ vetos a few times per month resulting in a total dead time less than 1\,ms, and does not influence ordinary operations. Additionally, using simulation data we find that supernovae closer than 800~pc will trigger Veto module resulting in a prescaling of the observed neutrino data., Comment: 28 pages, 18 figures. Submitted to PTEP
Published: 2024
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4. Measurements of the charge ratio and polarization of cosmic-ray muons with the Super-Kamiokande detector

Author: Kitagawa, H., Tada, T., Abe, K., Bronner, C., Hayato, Y., Hiraide, K., Hosokawa, 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., Han, S., Kajita, T., Okumura, K., Tashiro, T., Tomiya, T., Wang, X., Yoshida, S., Megias, G. D., Fernandez, P., Labarga, L., Ospina, N., Zaldivar, B., Pointon, B. W., Kearns, E., Raaf, J. L., Wan, L., Wester, T., Bian, J., Griskevich, N. J., Locke, S., Smy, M. B., Sobel, H. W., Takhistov, V., Yankelevich, A., Hill, J., Jang, M. C., Lee, S. H., Moon, D. H., Park, R. G., Bodur, B., Scholberg, K., Walter, C. W., Beauchêne, A., Drapier, O., Giampaolo, A., Mueller, Th. A., Santos, A. D., Paganini, P., Quilain, B., Rogly, R., Nakamura, T., Jang, J. S., Machado, L. N., Learned, J. G., Choi, K., Iovine, N., Cao, S., Anthony, L. H. V., Martin, D., Prouse, N. W., Scott, M., Sztuc, A. A., Uchida, Y., Berardi, V., Calabria, N. F., Catanesi, M. G., Radicioni, E., Langella, A., De Rosa, G., Collazuol, G., Iacob, F., Lamoureux, M., Mattiazzi, M., Ludovici, L., Gonin, M., Périssé, L., Pronost, G., Fujisawa, C., Maekawa, Y., Nishimura, Y., Okazaki, R., Akutsu, R., Friend, M., Hasegawa, T., Ishida, T., Kobayashi, T., Jakkapu, M., Matsubara, T., Nakadaira, T., Nakamura, K., Oyama, Y., Sakashita, K., Sekiguchi, T., Tsukamoto, T., Bhuiyan, N., Burton, G. T., Di Lodovico, F., Gao, J., Goldsack, A., Katori, T., Migenda, J., Ramsden, R. M., Xie, Z., Zsoldos, S., Kotsar, Y., Ozaki, H., Suzuki, A. T., Takagi, Y., Takeuchi, Y., Zhong, H., Feng, J., Feng, L., Hu, J. R., Hu, Z., Kawaue, M., Kikawa, T., Mori, M., Nakaya, T., Wendell, R. A., Yasutome, K., Jenkins, S. J., McCauley, N., Mehta, P., Tarant, A., Wilking, M. J., Fukuda, Y., Itow, Y., Menjo, H., Ninomiya, K., Yoshioka, Y., Lagoda, J., Mandal, M., Mijakowski, P., Prabhu, Y. S., Zalipska, J., Jia, M., Jiang, J., Jung, C. K., Shi, W., Yanagisawa, C., Harada, M., Hino, Y., Ishino, H., Koshio, Y., Nakanishi, F., Sakai, S., Tano, T., Ishizuka, T., Barr, G., Barrow, D., Cook, L., Samani, S., Wark, D., Holin, A., Nova, F., Jung, S., Yang, B. S., Yang, J. Y., Yoo, J., Fannon, J. E. P., Kneale, L., Malek, M., McElwee, J. M., Thiesse, M. D., Thompson, L. F., Wilson, S. T., Okazawa, H., Lakshmi, S. M., Kim, S. B., Kwon, E., Seo, J. W., Yu, I., Ichikawa, A. K., Nakamura, K. D., Tairafune, S., Nishijima, K., Eguchi, A., Nakagiri, K., Nakajima, Y., Shima, S., Taniuchi, N., Watanabe, E., Yokoyama, M., de Perio, P., Fujita, S., Jesús-Valls, C., Martens, K., Tsui, K. M., Vagins, M. R., Xia, J., Izumiyama, S., Kuze, M., Matsumoto, R., Terada, K., Ishitsuka, M., Ito, H., Kinoshita, T., Ommura, Y., Shigeta, N., Shinoki, M., Suganuma, T., Yamauchi, K., Yoshida, T., Martin, J. F., Tanaka, H. A., Towstego, T., Gaur, R., Gousy-Leblanc, V., Hartz, M., Konaka, A., Li, X., Chen, S., Xu, B. D., Zhang, B., Posiadala-Zezula, M., Boyd, S. B., Edwards, R., Hadley, D., Nicholson, M., O'Flaherty, M., Richards, B., Ali, A., Jamieson, B., Amanai, S., Marti, Ll., Minamino, A., Pintaudi, G., Sano, S., Suzuki, S., and Wada, K.
Subjects: High Energy Physics - Experiment, Astrophysics - High Energy Astrophysical Phenomena
Abstract: We present the results of the charge ratio ($R$) and polarization ($P^{\mu}_{0}$) measurements using the decay electron events collected from 2008 September to 2022 June by the Super-Kamiokande detector. Because of its underground location and long operation, we performed high precision measurements by accumulating cosmic-ray muons. We measured the muon charge ratio to be $R=1.32 \pm 0.02$ $(\mathrm{stat.}{+}\mathrm{syst.})$ at $E_{\mu}\cos \theta_{\mathrm{Zenith}}=0.7^{+0.3}_{-0.2}$ $\mathrm{TeV}$, where $E_{\mu}$ is the muon energy and $\theta_{\mathrm{Zenith}}$ is the zenith angle of incoming cosmic-ray muons. This result is consistent with the Honda flux model while this suggests a tension with the $\pi K$ model of $1.9\sigma$. We also measured the muon polarization at the production location to be $P^{\mu}_{0}=0.52 \pm 0.02$ $(\mathrm{stat.}{+}\mathrm{syst.})$ at the muon momentum of $0.9^{+0.6}_{-0.1}$ $\mathrm{TeV}/c$ at the surface of the mountain; this also suggests a tension with the Honda flux model of $1.5\sigma$. This is the most precise measurement ever to experimentally determine the cosmic-ray muon polarization near $1~\mathrm{TeV}/c$. These measurement results are useful to improve the atmospheric neutrino simulations., Comment: 29 pages, 45 figures
Published: 2024

5. Second gadolinium loading to Super-Kamiokande

Author: Abe, K., Bronner, C., Hayato, Y., Hiraide, K., Hosokawa, 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., Sato, K., Sekiya, H., Shiba, H., Shimizu, K., Shiozawa, M., Sonoda, Y., Suzuki, Y., Takeda, A., Takemoto, Y., Tanaka, H., Yano, T., Han, S., Kajita, T., Okumura, K., Tashiro, T., Tomiya, T., Wang, X., Yoshida, S., Fernandez, P., Labarga, L., Ospina, N., Zaldivar, B., Pointon, B. W., Kearns, E., Raaf, J. L., Wan, L., Wester, T., Bian, J., Griskevich, N. J., Smy, M. B., Sobel, H. W., Takhistov, V., Yankelevich, A., Hill, J., Jang, M. C., Lee, S. H., Moon, D. H., Park, R. G., Bodur, B., Scholberg, K., Walter, C. W., Beauchene, A., Drapier, O., Giampaolo, A., Mueller, Th. A., Santos, A. D., Paganini, P., Quilain, B., Rogly, R., Nakamura, T., Jang, J. S., Machado, L. N., Learned, J. G., Choi, K., Iovine, N., Cao, S., Anthony, L. H. V., Martin, D., Prouse, N. W., Scott, M., Uchida, Y., Berardi, V., Calabria, N. F., Catanesi, M. G., Radicioni, E., Langella, A., De Rosa, G., Collazuol, G., Iacob, F., Mattiazzi, M., Ludovici, L., Gonin, M., Perisse, L., Pronost, G., Fujisawa, C., Maekawa, Y., Nishimura, Y., Okazaki, R., Akutsu, R., Friend, M., Hasegawa, T., Ishida, T., Kobayashi, T., Jakkapu, M., Matsubara, T., Nakadaira, T., Nakamura, K., Oyama, Y., Sakashita, K., Sekiguchi, T., Tsukamoto, T., Bhuiyan, N., Burton, G. T., Di Lodovico, F., Gao, J., Goldsack, A., Katori, T., Migenda, J., Ramsden, R. M., Xie, Z., Zsoldos, S., Suzuki, A. T., Takagi, Y., Takeuchi, Y., Zhong, H., Feng, J., Feng, L., Hu, J. R., Hu, Z., Kawaue, M., Kikawa, T., Mori, M., Nakaya, T., Wendell, R. A., Yasutome, K., Jenkins, S. J., McCauley, N., Mehta, P., Tarant, A., Wilking, M. J., Fukuda, Y., Itow, Y., Menjo, H., Ninomiya, K., Yoshioka, Y., Lagoda, J., Mandal, M., Mijakowski, P., Prabhu, Y. S., Zalipska, J., Jia, M., Jiang, J., Shi, W., Yanagisawa, C., Harada, M., Hino, Y., Ishino, H., Koshio, Y., Nakanishi, F., Sakai, S., Tada, T., Tano, T., Ishizuka, T., Barr, G., Barrow, D., Cook, L., Samani, S., Wark, D., Holin, A., Nova, F., Jung, S., Yang, B. S., Yang, J. Y., Yoo, J., Fannon, J. E. P., Kneale, L., Malek, M., McElwee, J. M., Thiesse, M. D., Thompson, L. F., Wilson, S. T., Okazawa, H., Lakshmi, S. M., Kim, S. B., Kwon, E., Seo, J. W., Yu, I., Ichikawa, A. K., Tairafune, S., Nishijima, K., Eguchi, A., Nakagiri, K., Nakajima, Y., Shima, S., Taniuchi, N., Watanabe, E., Yokoyama, M., de Perio, P., Fujita, S., Jesus-Valls, C., Martens, K., Tsui, K. M., Vagins, M. R., Xia, J., Izumiyama, S., Kuze, M., Matsumoto, R., Terada, K., Ishitsuka, M., Ito, H., Ommura, Y., Shigeta, N., Shinoki, M., Yamauchi, K., Yoshida, T., Gaur, R., Gousy-Leblanc, V., Hartz, M., Konaka, A., Li, X., Chen, S., Xu, B. D., Zhang, B., Posiadala-Zezula, M., Boyd, S. B., Edwards, R., Hadley, D., Nicholson, M., O'Flaherty, M., Richards, B., Ali, A., Jamieson, B., Amanai, S., Marti, Ll., Minamino, A., Suzuki, S., Scovell, P. R., Meehan, E., Bandac, I., Pena-Garay, C., Perez, J., Gileva, O., Lee, E. K., Leonard, D. S., Sakakieda, Y., Sakaguchi, A., Sueki, K., Takaku, Y., and Yamasaki, S.
Subjects: Physics - Instrumentation and Detectors, Astrophysics - High Energy Astrophysical Phenomena
Abstract: The first loading of gadolinium (Gd) into Super-Kamiokande in 2020 was successful, and the neutron capture efficiency on Gd reached 50\%. To further increase the Gd neutron capture efficiency to 75\%, 26.1 tons of $\rm Gd_2(\rm SO_4)_3\cdot \rm 8H_2O$ was additionally loaded into Super-Kamiokande (SK) from May 31 to July 4, 2022. As the amount of loaded $\rm Gd_2(\rm SO_4)_3\cdot \rm 8H_2O$ was doubled compared to the first loading, the capacity of the powder dissolving system was doubled. We also developed new batches of gadolinium sulfate with even further reduced radioactive impurities. In addition, a more efficient screening method was devised and implemented to evaluate these new batches of $\rm Gd_2(\rm SO_4)_3\cdot \rm 8H_2O$. Following the second loading, the Gd concentration in SK was measured to be $333.5\pm2.5$ ppm via an Atomic Absorption Spectrometer (AAS). From the mean neutron capture time constant of neutrons from an Am/Be calibration source, the Gd concentration was independently measured to be 332.7 $\pm$ 6.8(sys.) $\pm$ 1.1(stat.) ppm, consistent with the AAS result. Furthermore, during the loading the Gd concentration was monitored continually using the capture time constant of each spallation neutron produced by cosmic-ray muons,and the final neutron capture efficiency was shown to become 1.5 times higher than that of the first loaded phase, as expected., Comment: 34 pages, 13 figures, submitted to Nuclear Inst. and Methods in Physics Research, A
Published: 2024
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6. Performance of SK-Gd's Upgraded Real-time Supernova Monitoring System

Author: Kashiwagi, Y., Abe, K., Bronner, C., Hayato, Y., Hiraide, K., Hosokawa, K., Ieki, K., Ikeda, M., Kameda, J., Kanemura, Y., Kaneshima, R., Kataoka, Y., Miki, S., Mine, S., Miura, M., Moriyama, S., Nakano, Y., Nakahata, M., Nakayama, S., Noguchi, Y., Sato, K., Sekiya, H., Shiba, H., Shimizu, K., Shiozawa, M., Sonoda, Y., Suzuki, Y., Takeda, A., Takemoto, Y., Tanaka, H., Yano, T., Han, S., Kajita, T., Okumura, K., Tashiro, T., Tomiya, T., Wang, X., Yoshida, S., Fernandez, P., Labarga, L., Ospina, N., Zaldivar, B., Pointn, B. W., Kearns, E., Raaf, J. L., Wan, L., Wester, T., Bian, J., Griskevich, N. J., Locke, S., Smy, M. B., Sobel, H. W., Takhistov, V., Yankelevich, A., Hill, J., Jang, M. C., Lee, S. H., Moon, D. H., Park, R. G., Bodur, B., Scholberg, K., Walter, C. W., Beauchêne, A., Drapier, O., Giampaolo, A., Mueller, Th. A., Santos, A. D., Paganini, P., Quilain, B., Rogly, R., Nakamura, T., Jang, J. S., Machado, L. N., Learned, J. G., Choi, K., Iovine, N., Cao, S., Anthony, L. H. V., Martin, D., Prouse, N. W., Scott, M., Sztuc, A. A., Uchida, Y., Berardi, V., Catanesi, M. G., Radicioni, E., Calabria, N. F., Langella, A., De Rosa, G., Collazuol, G., Iacob, F., Mattiazzi, M., Ludovici, L., Gonin, M., Périssé, L., Pronost, G., Fujisawa, C., Maekawa, Y., Nishimura, Y., Okazaki, R., Akutsu, R., Friend, M., Hasegawa, T., Ishida, T., Kobayashi, T., Jakkapu, M., Matsubara, T., Nakadaira, T., Nakamura, K., Oyama, Y., Sakashita, K., Sekiguchi, T., Tsukamoto, T., Bhuiyan, N., Burton, G. T., Di Lodovico, F., Gao, J., Goldsack, A., Katori, T., Migenda, J., Ramsden, R. M., Xie, Z., Zsoldos, S., Suzuki, A. T., Takagi, Y., Takeuchi, Y., Zhong, H., Feng, J., Feng, L., Hu, J. R., Hu, Z., Kawaue, M., Kikawa, T., Mori, M., Nakaya, T., Wendell, R. A., Yasutome, K., Jenkins, S. J., McCauley, N., Mehta, P., Tarrant, A., Fukuda, Y., Itow, Y., Menjo, H., Ninomiya, K., Yoshioka, Y., Lagoda, J., Lakshmi, S. M., Mandal, M., Mijakowski, P., Prabhu, Y. S., Zalipska, J., Jia, M., Jiang, J., Jung, C. K., Shi, W., Wilking, M. J., Yanagisawa, C., Harada, M., Hino, Y., Ishino, H., Koshio, Y., Nakanishi, F., Sakai, S., Tada, T., Tano, T., Ishizuka, T., Barr, G., Barrow, D., Cook, L., Samani, S., Wark, D., Holin, A., Nova, F., Jung, S., Yang, B. S., Yang, J. Y., Yoo, J., Fannon, J. E. P., Kneale, L., Malek, M., McElwee, J. M., Thiesse, M. D., Thompson, L. F., Wilson, S. T., Okazawa, H., Kim, S. B., Kwon, E., Seo, J. W., Yu, I., Ichikawa, A. K., Nakamura, K. D., Tairafune, S., Nishijima, K., Eguchi, A., Nakagiri, K., Nakajima, Y., Shima, S., Taniuchi, N., Watanabe, E., Yokoyama, M., de Perio, P., Fujita, S., Jesús-Valls, C., Martens, K., Tsui, K. M., Vagins, M. R., Xia, J., Kuze, M., Izumiyama, S., Matsumoto, R., Ishitsuka, M., Ito, H., Ommura, Y., Shigeta, N., Shinoki, M., Yamauchi, K., Yoshida, T., Gaur, R., Gousy-Leblanc, V., Hartz, M., Konaka, A., Li, X., Chen, S., Xu, B. D., Zhang, B., Posiadala-Zezula, M., Boyd, S. B., Edwards, R., Hadley, D., Nicholson, M., O'Flaherty, M., Richards, B., Ali, A., Jamieson, B., Amanai, S., Marti, Ll., Minamino, A., and Suzuki, S.
Subjects: Astrophysics - High Energy Astrophysical Phenomena
Abstract: Among multi-messenger observations of the next galactic core-collapse supernova, Super-Kamiokande (SK) plays a critical role in detecting the emitted supernova neutrinos, determining the direction to the supernova (SN), and notifying the astronomical community of these observations in advance of the optical signal. On 2022, SK has increased the gadolinium dissolved in its water target (SK-Gd) and has achieved a Gd concentration of 0.033%, resulting in enhanced neutron detection capability, which in turn enables more accurate determination of the supernova direction. Accordingly, SK-Gd's real-time supernova monitoring system (Abe te al. 2016b) has been upgraded. SK_SN Notice, a warning system that works together with this monitoring system, was released on December 13, 2021, and is available through GCN Notices (Barthelmy et al. 2000). When the monitoring system detects an SN-like burst of events, SK_SN Notice will automatically distribute an alarm with the reconstructed direction to the supernova candidate within a few minutes. In this paper, we present a systematic study of SK-Gd's response to a simulated galactic SN. Assuming a supernova situated at 10 kpc, neutrino fluxes from six supernova models are used to characterize SK-Gd's pointing accuracy using the same tools as the online monitoring system. The pointing accuracy is found to vary from 3-7$^\circ$ depending on the models. However, if the supernova is closer than 10 kpc, SK_SN Notice can issue an alarm with three-degree accuracy, which will benefit follow-up observations by optical telescopes with large fields of view., Comment: 38 pages, 29 figures, 6 tables
Published: 2024

7. Solar neutrino measurements using the full data period of Super-Kamiokande-IV

Author: Collaboration, Super-Kamiokande, Abe, K., Bronner, C., Hayato, Y., Hiraide, K., Hosokawa, K., Ieki, K., Ikeda, M., Imaizumi, S., Iyogi, K., Kameda, J., Kanemura, Y., Kaneshima, R., Kashiwagi, Y., Kataoka, Y., Kato, Y., Kishimoto, Y., Miki, S., Mine, S., Miura, M., Mochizuki, T., Moriyama, S., Nagao, Y., Nakahata, M., Nakano, Y., Nakayama, S., Noguchi, Y., Okada, T., Okamoto, K., Orii, A., 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., Han, S., Kajita, T., Okumura, K., Tashiro, T., Tomiya, T., Wang, R., Wang, X., Yoshida, S., Bravo-Berguno, D., Fernandez, P., Labarga, L., Ospina, N., Zaldivar, B., Pointon, B. W., Blaszczyk, F. d. M., Kachulis, C., Kearns, E., Raaf, J. L., Stone, J. L., Wan, L., Wester, T., Bian, J., Griskevich, N. J., Kropp, W. R., Locke, S., Smy, M. B., Sobel, H. W., Takhistov, V., Weatherly, P., Yankelevich, A., Ganezer, K. S., Hill, J., Jang, M. C., Kim, J. Y., Lee, S., Lim, I. T., Moon, D. H., Park, R. G., Bodur, B., Scholberg, K., Walter, C. W., Beauchene, A., Bernard, L., Coffani, A., Drapier, O., Hedri, S. El, Giampaolo, A., Imber, J., Mueller, Th. A., Paganini, P., Rogly, R., Quilain, B., Santos, A., Nakamura, T., Jang, J. S., Machado, L. N., Learned, J. G., Matsuno, S., Iovine, N., Choi, K., Cao, S., Anthony, L. H. V., Litchfield, R. P., Prouse, N., Marin, D., Scott, M., Sztuc, A. A., Uchida, Y., Berardi, V., Catanesi, M. G., Intonti, R. A., Radicioni, E., Calabria, N. F., De Rosa, G., Langella, A., Collazuol, G., Iacob, F., Lamoureux, M., Mattiazzi, M., Ludovici, L., Gonin, M., Perisse, L., Pronost, G., Fujisawa, C., Maekawa, Y., Nishimura, Y., Okazaki, 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., Bhuiyan, N., Burton, G. T., Gao, J., Goldsack, A., Katori, T., Di Lodovico, F., Migenda, J., Sedgwick, S. Molina, Ramsden, R. M., Taani, M., Xie, Z., Zsoldos, S., Abe, KE., Hasegawa, M., Isobe, Y., Kotsar, Y., Miyabe, H., Ozaki, H., Shiozawa, T., Sugimoto, T., Suzuki, A. T., Takagi, Y., Takeuchi, Y., Yamamoto, S., Zhong, H., Ashida, Y., Feng, J., Feng, L., Hayashino, T., Hirota, S., Hu, J. R., Hu, Z., Jiang, M., Kawaue, M., Kikawa, T., Mori, M., Nakamura, KE., Nakaya, T., Wendell, R. A., Yasutome, K., Jenkins, S. J., McCauley, N., Mehta, P., Pritchard, A., Tarrant, A., Wilking, M. J., Fukuda, Y., Itow, Y., Menjo, H., Murase, M., Ninomiya, K., Niwa, T., Tsukada, M., Yoshioka, Y., Frankiewicz, K., Lagoda, J., Mandal, M., Mijakowski, P., Prabhu, Y. S., Zalipska, J., Jiang, J., Jia, M., Jung, C. K., Palomino, J. L., Santucci, G., Shi, W., Vilela, C., Yanagisawa, C., Fukuda, D., Hagiwara, K., Harada, M., Hino, Y., Horai, T., Ishino, H., Ito, S., Kitagawa, H., Koshio, Y., Ma, W., Nakanishi, F., Piplani, N., Sakai, S., Sakuda, M., Tada, T., Tano, T., Xu, C., Yamaguchi, R., Ishizuka, T., Kuno, Y., Barr, G., Barrow, D., Cook, L., Samani, S., Simpson, C., Wark, D., Holin, A. M., Nova, F., Jung, S., Yang, B., Yang, J. Y., Yoo, J., Fannon, J. E. P., Kneale, L., Malek, M., McElwee, J. M., Stone, O., Thiesse, M. D., Thompson, L. F., Wilson, S. T., Okazawa, H., Lakshmi, S. M., Choi, Y., Kim, S. B., Kwon, E., Seo, J. W., Yu, I., Ichikawa, A. K., Tairahune, S., Nishijima, K., Eguchi, A., Iwamoto, K., Nakagiri, K., Nakajima, Y., Ogawa, N., Shima, S., Watanabe, E., Yokoyama, M., Calland, R. G., Fujita, S., Jesus-Valls, C., Junjie, X., Ming, T. K., de Perio, P., Martens, K., Murdoch, M., Vagins, M. R., Izumiyama, S., Kuze, M., Matsumoto, R., Okajima, Y., Tanaka, M., Yoshida, T., Inomoto, M., Ishitsuka, M., Ito, H., Kinoshita, T., Ohta, K., Ommura, Y., Shinoki, M., Shigeta, N., Suganuma, T., Yamaguchi, K., Martin, J. F., Nantais, C. M., Tanaka, H. A., Towstego, T., Gaur, R., Gousy-Leblanc, V., Hartz, M., Konaka, A., Li, X., Chen, S., Xu, B. D., Zhang, B., Berkman, S., Posiadala-Zezula, M., Boyd, S. B., Edwards, R., Hadley, D., Nicholson, M., O'Flaherty, M., Richards, B., Ali, A., Jamieson, B., Walker, J., Amanai, S., Marti, Ll., Minamino, A., Pintaudi, G., Sano, S., Sasaki, R., Suzuki, S., and Wada, K.
Subjects: High Energy Physics - Experiment
Abstract: An analysis of solar neutrino data from the fourth phase of Super-Kamiokande~(SK-IV) from October 2008 to May 2018 is performed and the results are presented. The observation time of the data set of SK-IV corresponds to $2970$~days and the total live time for all four phases is $5805$~days. For more precise solar neutrino measurements, several improvements are applied in this analysis: lowering the data acquisition threshold in May 2015, further reduction of the spallation background using neutron clustering events, precise energy reconstruction considering the time variation of the PMT gain. The observed number of solar neutrino events in $3.49$--$19.49$ MeV electron kinetic energy region during SK-IV is $65,443^{+390}_{-388}\,(\mathrm{stat.})\pm 925\,(\mathrm{syst.})$ events. Corresponding $\mathrm{^{8}B}$ solar neutrino flux is $(2.314 \pm 0.014\, \rm{(stat.)} \pm 0.040 \, \rm{(syst.)}) \times 10^{6}~\mathrm{cm^{-2}\,s^{-1}}$, assuming a pure electron-neutrino flavor component without neutrino oscillations. The flux combined with all SK phases up to SK-IV is $(2.336 \pm 0.011\, \rm{(stat.)} \pm 0.043 \, \rm{(syst.)}) \times 10^{6}~\mathrm{cm^{-2}\,s^{-1}}$. Based on the neutrino oscillation analysis from all solar experiments, including the SK $5805$~days data set, the best-fit neutrino oscillation parameters are $\rm{sin^{2} \theta_{12,\,solar}} = 0.306 \pm 0.013 $ and $\Delta m^{2}_{21,\,\mathrm{solar}} = (6.10^{+ 0.95}_{-0.81}) \times 10^{-5}~\rm{eV}^{2}$, with a deviation of about 1.5$\sigma$ from the $\Delta m^{2}_{21}$ parameter obtained by KamLAND. The best-fit neutrino oscillation parameters obtained from all solar experiments and KamLAND are $\sin^{2} \theta_{12,\,\mathrm{global}} = 0.307 \pm 0.012 $ and $\Delta m^{2}_{21,\,\mathrm{global}} = (7.50^{+ 0.19}_{-0.18}) \times 10^{-5}~\rm{eV}^{2}$., Comment: 47 pages, 61 figures
Published: 2023
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8. Atmospheric neutrino oscillation analysis with neutron tagging and an expanded fiducial volume in Super-Kamiokande I-V

Author: Collaboration, Super-Kamiokande, Wester, T., Abe, K., Bronner, C., Hayato, Y., Hiraide, K., Hosokawa, 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., Sato, K., Sekiya, H., Shiba, H., Shimizu, K., Shiozawa, M., Sonoda, Y., Suzuki, Y., Takeda, A., Takemoto, Y., Tanaka, H., Yano, T., Han, S., Kajita, T., Okumura, K., Tashiro, T., Tomiya, T., Wang, X., Yoshida, S., Fernandez, P., Labarga, L., Ospina, N., Zaldivar, B., Pointon, B. W., Kearns, E., Raaf, J. L., Wan, L., Bian, J., Griskevich, N. J., Locke, S., Smy, M. B., Sobel, H. W., Takhistov, V., Yankelevich, A., Hill, J., Lee, S. H., Moon, D. H., Park, R. G., Bodur, B., Scholberg, K., Walter, C. W., Beauchene, A., Drapier, O., Giampaolo, A., Mueller, Th. A., Santos, A. D., Paganini, P., Quilain, B., Nakamura, T., Jang, J. S., Machado, L. N., Learned, J. G., Choi, K., Iovine, N., Cao, S., Anthony, L. H. V., Martin, D., Prouse, N. W., Scott, M., Sztuc, A. A., Uchida, Y., Berardi, V., Catanesi, M. G., Radicioni, E., Calabria, N. F., Langella, A., De Rosa, G., Collazuol, G., Iacob, F., Mattiazzi, M., Ludovici, L., Gonin, M., Pronost, G., Fujisawa, C., Maekawa, Y., Nishimura, Y., Okazaki, R., Akutsu, R., Friend, M., Hasegawa, T., Ishida, T., Kobayashi, T., Jakkapu, M., Matsubara, T., Nakadaira, T., Nakamura, K., Oyama, Y., Sakashita, K., Sekiguchi, T., Tsukamoto, T., Bhuiyan, N., Burton, G. T., Di Lodovico, F., Gao, J., Goldsack, A., Katori, T., Migenda, J., Ramsden, R., Xie, Z., Zsoldos, S., Suzuki, A. T., Takagi, Y., Takeuchi, Y., Zhong, H., Feng, J., Feng, L., Hu, J. R., Hu, Z., Kawaue, M., Kikawa, T., Mori, M., Nakaya, T., Wendell, R. A., Yasutome, K., Jenkins, S. J., McCauley, N., Mehta, P., Tarrant, A., 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., Shi, W., Wilking, M. J., Yanagisawa, C., Harada, M., Hino, Y., Ishino, H., Koshio, Y., Nakanishi, F., Sakai, S., Tada, T., Tano, T., Ishizuka, T., Barr, G., Barrow, D., Cook, L., Holin, A., Nova, F., Samani, S., Wark, D., Jung, S., Yang, B. S., Yang, J. Y., Yoo, J., Fannon, J. E. P., Kneale, L., Malek, M., McElwee, J. M., Thiesse, M. D., Thompson, L. F., Wilson, S. T., Okazawa, H., Kim, S. B., Kwon, E., Seo, J. W., Yu, I., Ichikawa, A. K., Nakamura, K. D., Tairafune, S., Nishijima, K., Koshiba, M., Eguchi, A., Nakagiri, K., Nakajima, Y., Shima, S., Taniuchi, N., Watanabe, E., Yokoyama, M., de Perio, P., Fujita, S., Martens, K., Tsui, K. M., Vagins, M. R., Xia, J., Izumiyama, S., Kuze, M., Matsumoto, R., Ishitsuka, M., Ito, H., Ommura, Y., Shigeta, N., Shinoki, M., Yamauchi, K., Yoshida, T., Gaur, R., Gousy-Leblanc, V., Hartz, M., Konaka, A., Li, X., Chen, S., Xu, B. D., Zhang, B., Posiadala-Zezula, M., Boyd, S. B., Edwards, R., Hadley, D., Nicholson, M., O'Flaherty, M., Richards, B., Ali, A., Jamieson, B., Amanai, S., Marti, Ll., Minamino, A., and Suzuki, S.
Subjects: High Energy Physics - Experiment
Abstract: We present a measurement of neutrino oscillation parameters with the Super-Kamiokande detector using atmospheric neutrinos from the complete pure-water SK I-V (April 1996-July 2020) data set, including events from an expanded fiducial volume. The data set corresponds to 6511.3 live days and an exposure of 484.2 kiloton-years. Measurements of the neutrino oscillation parameters $\Delta m^2_{32}$, $\sin^2\theta_{23}$, $\sin^2 \theta_{13}$, $\delta_{CP}$, and the preference for the neutrino mass ordering are presented with atmospheric neutrino data alone, and with constraints on $\sin^2 \theta_{13}$ from reactor neutrino experiments. Our analysis including constraints on $\sin^2 \theta_{13}$ favors the normal mass ordering at the 92.3% level., Comment: 24 pages, 18 figures
Published: 2023
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9. Measurement of the neutrino-oxygen neutral-current quasielastic cross section using atmospheric neutrinos in the SK-Gd experiment

Author: Sakai, S., Abe, K., Bronner, C., Hayato, Y., Hiraide, K., Hosokawa, 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., Sato, K., Sekiya, H., Shiba, H., Shimizu, K., Shiozawa, M., Sonoda, Y., Suzuki, Y., Takeda, A., Takemoto, Y., Tanaka, H., Yano, T., Han, S., Kajita, T., Okumura, K., Tashiro, T., Tomiya, T., Wang, X., Yoshida, S., Fernandez, P., Labarga, L., Ospina, N., Zaldivar, B., Pointon, B. W., Kearns, E., Raaf, J. L., Wan, L., Wester, T., Bian, J., Griskevich, N. J., Locke, S., Smy, M. B., Sobel, H. W., Takhistov, V., Yankelevich, A., Hill, J., Jang, M. C., Lee, S. H., Moon, D. H., Park, R. G., Bodur, B., Scholberg, K., Walter, C. W., Beauchene, A., Drapier, O., Giampaolo, A., Mueller, Th. A., Santos, A. D., Paganini, P., Quilain, B., Nakamura, T., Jang, J. S., Machado, L. N., Learned, J. G., Choi, K., Iovine, N., Cao, S., Anthony, L. H. V., Martin, D., Prouse, N. W., Scott, M., Sztuc, A. A., Uchida, Y., Berardi, V., Calabria, N. F., Catanesi, M. G., Radicioni, E., Langella, A., De Rosa, G., Collazuol, G., Iacob, F., Mattiazzi, M., Ludovici, L., Gonin, M., Pronost, G., Fujisawa, C., Maekawa, Y., Nishimura, Y., Okazaki, R., Akutsu, R., Friend, M., Hasegawa, T., Ishida, T., Kobayashi, T., Jakkapu, M., Matsubara, T., Nakadaira, T., Nakamura, K., Oyama, Y., Sakashita, K., Sekiguchi, T., Tsukamoto, T., Bhuiyan, N., Burton, G. T., Di Lodovico, F., Gao, J., Goldsack, A., Katori, T., Migenda, J., Ramsden, R. M., Xie, Z., Zsoldos, S., Suzuki, A. T., Takagi, Y., Zhong, H., Takeuchi, Y., Feng, J., Feng, L., Hu, J. R., Hu, Z., Kawaue, M., Kikawa, T., Mori, M., Nakaya, T., Wendell, R. A., Yasutome, K., Jenkins, S. J., McCauley, N., Mehta, P., Tarant, A., Fukuda, Y., Itow, Y., Menjo, H., Ninomiya, K., Yoshioka, Y., Lagoda, J., Lakshmi, S. M., Mandal, M., Mijakowski, P., Prabhu, Y. S., Zalipska, J., Jia, M., Jiang, J., Jung, C. K., Shi, W., Wilking, M. J., Yanagisawa, C., Harada, M., Hino, Y., Ishino, H., Koshio, Y., Nakanishi, F., Tada, T., Tano, T., Ishizuka, T., Barr, G., Barrow, D., Cook, L., Samani, S., Wark, D., Holin, A., Nova, F., Jung, S., Yang, B. S., Yang, J. Y., Yoo, J., Fannon, J. E. P., Kneale, L., Malek, M., McElwee, J. M., Thiesse, M. D., Thompson, L. F., Wilson, S. T., Okazawa, H., Kim, S. B., Kwon, E., Seo, J. W., Yu, I., Ichikawa, A. K., Nakamura, K. D., Tairafune, S., Nishijima, K., Eguchi, A., Nakagiri, K., Nakajima, Y., Shima, S., Taniuchi, N., Watanabe, E., Yokoyama, M., de Perio, P., Fujita, S., Martens, K., Tsui, K. M., Vagins, M. R., Xia, J., Izumiyama, S., Kuze, M., Matsumoto, R., Ishitsuka, M., Ito, H., Ommura, Y., Shigeta, N., Shinoki, M., Yamauchi, K., Yoshida, T., Gaur, R., Gousy-Leblanc, V., Hartz, M., Konaka, A., Li, X., Chen, S., Xu, B. D., Zhang, B., Posiadala-Zezula, M., Boyd, S. B., Edwards, R., Hadley, D., Nicholson, M., O'Flaherty, M., Richards, B., Ali, A., Jamieson, B., Amanai, S., Marti, Ll., Minamino, A., and Suzuki, S.
Subjects: High Energy Physics - Experiment
Abstract: We report the first measurement of the atmospheric neutrino-oxygen neutral-current quasielastic (NCQE) cross section in the gadolinium-loaded Super-Kamiokande (SK) water Cherenkov detector. In June 2020, SK began a new experimental phase, named SK-Gd, by loading 0.011% by mass of gadolinium into the ultrapure water of the SK detector. The introduction of gadolinium to ultrapure water has the effect of improving the neutron-tagging efficiency. Using a 552.2 day data set from August 2020 to June 2022, we measure the NCQE cross section to be 0.74 $\pm$ 0.22(stat.) $^{+0.85}_{-0.15}$ (syst.) $\times$ 10$^{-38}$ cm$^{2}$/oxygen in the energy range from 160 MeV to 10 GeV, which is consistent with the atmospheric neutrino-flux-averaged theoretical NCQE cross section and the measurement in the SK pure-water phase within the uncertainties. Furthermore, we compare the models of the nucleon-nucleus interactions in water and find that the Binary Cascade model and the Liege Intranuclear Cascade model provide a somewhat better fit to the observed data than the Bertini Cascade model. Since the atmospheric neutrino-oxygen NCQE reactions are one of the main backgrounds in the search for diffuse supernova neutrino background (DSNB), these new results will contribute to future studies - and the potential discovery - of the DSNB in SK., Comment: 8 pages, 3 figures
Published: 2023

10. Search for Periodic Time Variations of the Solar $^8$B Neutrino Flux between 1996 and 2018 in Super-Kamiokande

Author: Abe, K., Bronner, C., Hayato, Y., Hiraide, K., Hosokawa, 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., Sato, K., Sekiya, H., Shiba, H., Shimizu, K., Shiozawa, M., Sonoda, Y., Suzuki, Y., Takeda, A., Takemoto, Y., Tanaka, H., Yano, T., Han, S., Kajita, T., Okumura, K., Tashiro, T., Tomiya, T., Wang, X., Yoshida, S., Fernandez, P., Labarga, L., Ospina, N., Zaldivar, B., Pointon, B. W., Kearns, E., Raaf, J. L., Wan, L., Wester, T., Bian, J., Griskevich, N. J., Locke, S., Smy, M. B., Sobel, H. W., Takhistov, V., Yankelevich, A., Hill, J., Lee, S. H., Moon, D. H., Park, R. G., Jang, M. C., Bodur, B., Scholberg, K., Walter, C. W., Beauchene, A., Drapier, O., Giampaolo, A., Mueller, Th. A., Santos, A. D., Paganini, P., Quilain, B., Nakamura, T., Jang, J. S., Machado, L. N., Learned, J. G., Choi, K., Iovine, N., Cao, S., Anthony, L. H. V., Martin, D., Prouse, N. W., Scott, M., Sztuc, A. A., Uchida, Y., Berardi, V., Catanesi, M. G., Radicioni, E., Calabria, N. F., Langella, A., De Rosa, G., Collazuol, G., Iacob, F., Mattiazzi, M., Ludovici, L., Gonin, M., Pronost, G., Fujisawa, C., Maekawa, Y., Nishimura, Y., Okazaki, R., Akutsu, R., Friend, M., Hasegawa, T., Ishida, T., Kobayashi, T., Jakkapu, M., Matsubara, T., Nakadaira, T., Nakamura, K., Oyama, Y., Sakashita, K., Sekiguchi, T., Tsukamoto, T., Bhuiyan, N., Burton, G. T., Di Lodovico, F., Gao, J., Goldsack, A., Katori, T., Migenda, J., Xie, Z., Ramsden, R. M., Zsoldos, S., Suzuki, A. T., Takagi, Y., Zhong, H., Takeuchi, Y., Feng, J., Feng, L., Hu, J. R., Hu, Z., Kikawa, T., Mori, M., Kawaue, M., Nakaya, T., Wendell, R. A., Yasutome, K., Jenkins, S. J., McCauley, N., Mehta, P., Tarant, A., Fukuda, Y., Itow, Y., Menjo, H., Ninomiya, K., Yoshioka, Y., 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., Shi, W., Harada, M., Hino, Y., Ishino, H., Koshio, Y., Nakanishi, F., Sakai, S., Tada, T., Tano, T., Ishizuka, T., Barr, G., Barrow, D., Cook, L., Samani, S., Wark, D., Holin, A., Nova, F., Yang, B. S., Yang, J. Y., Yoo, J., Jung, S., Fannon, J. E. P., Kneale, L., Malek, M., McElwee, J. M., Thiesse, M. D., Thompson, L. F., Wilson, S. T., Okazawa, H., Kim, S. B., Kwon, E., Seo, J. W., Yu, I., Ichikawa, A. K., Nakamura, K. D., Tairafune, S., Nishijima, K., Eguchi, A., Nakagiri, K., Nakajima, Y., Shima, S., Taniuchi, N., Watanabe, E., Yokoyama, M., de Perio, P., Fujita, S., Martens, K., Tsui, K. M., Vagins, M. R., Xia, J., Izumiyama, S., Kuze, M., Matsumoto, R., Ishitsuka, M., Ito, H., Ommura, Y., Shigeta, N., Shinoki, M., Yamauchi, K., Yoshida, T., Gaur, R., Gousy-Leblanc, V., Hartz, M., Konaka, A., Li, X., Chen, S., Xu, B. D., Zhang, B., Posiadala-Zezula, M., Boyd, S. B., Edwards, R., Hadley, D., Nicholson, M., Flaherty, M. O, Richards, B., Ali, A., Jamieson, B., Amanai, S., Marti, Ll., Minamino, A., and Suzuki, S.
Subjects: High Energy Physics - Experiment
Abstract: We report a search for time variations of the solar $^8$B neutrino flux using 5804 live days of Super-Kamiokande data collected between May 31, 1996, and May 30, 2018. Super-Kamiokande measured the precise time of each solar neutrino interaction over 22 calendar years to search for solar neutrino flux modulations with unprecedented precision. Periodic modulations are searched for in a dataset comprising five-day interval solar neutrino flux measurements with a maximum likelihood method. We also applied the Lomb-Scargle method to this dataset to compare it with previous reports. The only significant modulation found is due to the elliptic orbit of the Earth around the Sun. The observed modulation is consistent with astronomical data: we measured an eccentricity of (1.53$\pm$0.35)\%, and a perihelion shift of ($-$1.5$\pm$13.5) days., Comment: 8 pages, 5 figures, 2 tables, and data file: "sksolartimevariation5804d.txt" (the data file updated with additional 3 columns -- R^2 correction, upper-error, lower-error)
Published: 2023

11. Search for astrophysical electron antineutrinos in Super-Kamiokande with 0.01wt% gadolinium-loaded water

Author: Harada, M., Abe, K., Bronner, C., Hayato, Y., Hiraide, K., Hosokawa, 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., Han, S., Kajita, T., Okumura, K., Tashiro, T., Tomiya, T., Wang, X., Yoshida, S., Megias, G. D., Fernandez, P., Labarga, L., Ospina, N., Zaldivar, B., Pointon, B. W., Kearns, E., Raaf, J. L., Wan, L., Wester, T., Bian, J., Griskevich, N. J., Locke, S., Smy, M. B., Sobel, H. W., Takhistov, V., Yankelevich, A., Hill, J., Lee, S. H., Moon, D. H., Park, R. G., Bodur, B., Scholberg, K., Walter, C. W., Beauchene, A., Drapier, O., Giampaolo, A., Mueller, Th. A., Santos, A. D., Paganini, P., Quilain, B., Ishizuka, T., Nakamura, T., Jang, J. S., Learned, J. G., Choi, K., Iovine, N., Cao, S., Anthony, L. H. V., Martin, D., Scott, M., Sztuc, A. A., Uchida, Y., Berardi, V., Catanesi, M. G., Radicioni, E., Calabria, N. F., Langella, A., Machado, L. N., De Rosa, G., Collazuol, G., Iacob, F., Lamoureux, M., Mattiazzi, M., Ludovici, L., Gonin, M., Pronost, G., Fujisawa, C., Maekawa, Y., Nishimura, Y., Okazaki, R., Akutsu, R., Friend, M., Hasegawa, T., Ishida, T., Kobayashi, T., Jakkapu, M., Matsubara, T., Nakadaira, T., Nakamura, K., Oyama, Y., Sakashita, K., Sekiguchi, T., Tsukamoto, T., Bhuiyan, N., Burton, G. T., Di Lodovico, F., Gao, J., Goldsack, A., Katori, T., Migenda, J., Xie, Z., Zsoldos, S., Kotsar, Y., Ozaki, H., Suzuki, A. T., Takagi, Y., Takeuchi, Y., Feng, J., Feng, L., Hu, J. R., Hu, Z., Kikawa, T., Mori, M., Nakaya, T., Wendell, R. A., Yasutome, K., Jenkins, S. J., McCauley, N., Mehta, P., Tarrant, A., 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., Hino, Y., Ishino, H., Kitagawa, H., Koshio, Y., Nakanishi, F., Sakai, S., Tada, T., Tano, T., Barr, G., Barrow, D., Cook, L., Samani, S., Wark, D., Holin, A., Nova, F., Yang, B. S., Yang, J. Y., Yoo, J., Fannon, J. E. P., Kneale, L., Malek, M., McElwee, J. M., Thiesse, M. D., Thompson, L. F., Wilson, S. T., Okazawa, H., Kim, S. B., Kwon, E., Seo, J. W., Yu, I., Ichikawa, A. K., Nakamura, K. D., Tairafune, S., Nishijima, K., Nakagiri, K., Nakajima, Y., Shima, S., Taniuchi, N., Watanabe, E., Yokoyama, M., de Perio, P., Martens, K., Tsui, K. M., Vagins, M. R., Xia, J., Kuze, M., Izumiyama, S., Matsumoto, R., Ishitsuka, M., Ito, H., Kinoshita, T., Ommura, Y., Shigeta, N., Shinoki, M., Suganuma, T., Yamauchi, K., Martin, J. F., Tanaka, H. A., Towstego, T., Gaur, R., Gousy-Leblanc, V., Hartz, M., Konaka, A., Li, X., Prouse, N. W., Chen, S., Xu, B. D., Zhang, B., Posiadala-Zezula, M., Boyd, S. B., Edwards, R., Hadley, D., Nicholson, M., Flaherty, M. O, Richards, B., Ali, A., Jamieson, B., Marti, Ll., Minamino, A., Pintaudi, G., Sano, S., Suzuki, S., and Wada, K.
Subjects: Astrophysics - High Energy Astrophysical Phenomena, High Energy Physics - Experiment, Nuclear Experiment, Physics - Instrumentation and Detectors
Abstract: We report the first search result for the flux of astrophysical electron antineutrinos for energies O(10) MeV in the gadolinium-loaded Super-Kamiokande (SK) detector. In June 2020, gadolinium was introduced to the ultra-pure water of the SK detector in order to detect neutrons more efficiently. In this new experimental phase, SK-Gd, we can search for electron antineutrinos via inverse beta decay with efficient background rejection and higher signal efficiency thanks to the high efficiency of the neutron tagging technique. In this paper, we report the result for the initial stage of SK-Gd with a $22.5\times552$ $\rm kton\cdot day$ exposure at 0.01% Gd mass concentration. No significant excess over the expected background in the observed events is found for the neutrino energies below 31.3 MeV. Thus, the flux upper limits are placed at the 90% confidence level. The limits and sensitivities are already comparable with the previous SK result with pure-water ($22.5 \times 2970 \rm kton\cdot day$) owing to the enhanced neutron tagging.
Published: 2023
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12. Measurement of the cosmogenic neutron yield in Super-Kamiokande with gadolinium loaded water

Author: Collaboration, Super-Kamiokande, Shinoki, M., Abe, K., Hayato, Y., Hiraide, K., Hosokawa, 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., Han, S., Kajita, T., Okumura, K., Tashiro, T., Tomiya, T., Wang, X., Yoshida, S., Megias, G. D., Fernandez, P., Labarga, L., Ospina, N., Zaldivar, B., Pointon, B. W., Kearns, E., Raaf, J. L., Wan, L., Wester, T., Bian, J., Griskevich, N. J., Kropp, W. R., Locke, S., Smy, M. B., Sobel, H. W., Takhistov, V., Yankelevich, A., Hill, J., Lee, S. H., Moon, D. H., Park, R. G., Bodur, B., Scholberg, K., Walter, C. W., Beauchêne, A., Bernard, L., Coffani, A., Drapier, O., Hedri, S. El, Giampaolo, A., Mueller, Th. A., Santos, A. D., Paganini, P., Quilain, B., Ishizuka, T., Nakamura, T., Jang, J. S., Learned, J. G., Choi, K., Cao, S., Anthony, L. H. V., Martin, D., Scott, M., Sztuc, A. A., Uchida, Y., Berardi, V., Catanesi, M. G., Radicioni, E., Calabria, N. F., Langella, A., Machado, L. N., De Rosa, G., Collazuol, G., Iacob, F., Lamoureux, M., Mattiazzi, M., Ludovici, L., Gonin, M., Pronost, G., Fujisawa, C., Maekawa, Y., Nishimura, Y., Akutsu, R., Friend, M., Hasegawa, T., Ishida, T., Kobayashi, T., Jakkapu, M., Matsubara, T., Nakadaira, T., Nakamura, K., Oyama, Y., Sakashita, K., Sekiguchi, T., Tsukamoto, T., Bhuiyan, N., Boschi, T., Burton, G. T., Di Lodovico, F., Gao, J., Goldsack, A., Katori, T., Migenda, J., Taani, M., Xie, Z., Zsoldos, S., Kotsar, Y., Ozaki, H., Suzuki, A. T., Takeuchi, Y., Bronner, C., Feng, J., Kikawa, T., Mori, M., Nakaya, T., Wendell, R. A., Yasutome, K., Jenkins, S. J., McCauley, N., Mehta, P., Tarrant, A., 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., Nakanishi, F., Sakai, S., Barr, G., Barrow, D., Cook, L., Samani, S., Wark, D., Holin, A., Nova, F., Yang, J. Y., Yang, B. S., Yoo, J., Fannon, J. E. P., Kneale, L., Malek, M., McElwee, J. M., Stone, O., Thiesse, M. D., Thompson, L. F., Okazawa, H., Kim, S. B., Kwon, E., Seo, J. W., Yu, I., Ichikawa, A. K., Nakamura, K. D., Tairafune, S., Nishijima, K., Koshiba, M., Iwamoto, K., Nakagiri, K., Nakajima, Y., Shima, S., Taniuchi, N., Yokoyama, M., Martens, K., de Perio, P., Vagins, M. R., Xia, J., Kuze, M., Izumiyama, S., Inomoto, M., Ishitsuka, M., Ito, H., Kinoshita, T., Matsumoto, R., Ommura, Y., Shigeta, N., Suganuma, T., Yamauchi, K., Martin, J. F., Tanaka, H. A., Towstego, T., Gaur, R., Gousy-Leblanc, V., Hartz, M., Konaka, A., Li, X., Prouse, N. W., Chen, S., Xu, B. D., Zhang, B., Posiadala-Zezula, M., Boyd, S. B., Hadley, D., Nicholson, M., O'Flaherty, M., Richards, B., Ali, A., Jamieson, B., Marti, Ll., Minamino, A., Pintaudi, G., Sano, S., Suzuki, S., and Wada, K.
Subjects: High Energy Physics - Experiment
Abstract: Cosmic-ray muons that enter the Super-Kamiokande detector cause hadronic showers due to spallation in water, producing neutrons and radioactive isotopes. Those are a major background source for studies of MeV-scale neutrinos and searches for rare events. Since 2020, gadolinium was introduced in the ultra-pure water in the Super-Kamiokande detector to improve the detection efficiency of neutrons. In this study, the cosmogenic neutron yield was measured using data acquired during the period after the gadolinium loading. The yield was found to be $(2.76 \pm 0.02\,\mathrm{(stat.) \pm 0.19\,\mathrm{(syst.)}}) \times 10^{-4}\,\mu^{-1} \mathrm{g^{-1} cm^{2}}$ at 259 GeV of average muon energy at the Super-Kamiokande detector., Comment: 10 pages, 10 figures, 3 tables
Published: 2022

13. Direct dark matter searches with the full data set of XMASS-I

Author: XMASS Collaboration, Abe, K., Hiraide, K., Kato, N., Moriyama, S., Nakahata, M., Sato, K., Sekiya, H., Suzuki, T., Suzuki, Y., Takeda, A., Yang, B. S., Kim, N. Y., Kim, Y. D., Kim, Y. H., Itow, Y., Martens, K., Mason, A., Yamashita, M., Miuchi, K., Takeuchi, Y., Lee, K. B., Lee, M. K., Fukuda, Y., Ogawa, H., Ichimura, K., Kishimoto, Y., Nishijima, K., Fushimi, K., Xu, B. D., Kobayashi, K., and Nakamura, S.
Subjects: Astrophysics - Cosmology and Nongalactic Astrophysics, High Energy Physics - Experiment, Nuclear Experiment, Physics - Instrumentation and Detectors
Abstract: Various WIMP dark matter searches using the full data set of XMASS-I, a single-phase liquid xenon detector, are reported in this paper. Stable XMASS-I data taking accumulated a total live time of 1590.9 days between November 20, 2013 and February 1, 2019 with an analysis threshold of ${\rm 1.0\,keV_{ee}}$. In the latter half of data taking a lower analysis threshold of ${\rm 0.5\,keV_{ee}}$ was also available through a new low threshold trigger. Searching for a WIMP signal in the detector's 97~kg fiducial volume yielded a limit on the WIMP-nucleon scattering cross section of ${\rm 1.4\times 10^{-44}\, cm^{2}}$ for a ${\rm 60\,GeV/c^{2}}$ WIMP at the 90$\%$ confidence level. We also searched for WIMP induced annual modulation signatures in the detector's whole target volume, containing 832~kg of liquid xenon. For nuclear recoils of a ${\rm 8\,GeV/c^{2}}$ WIMP this analysis yielded a 90\% CL cross section limit of ${\rm 2.3\times 10^{-42}\, cm^{2}}$. At a WIMP mass of ${\rm 0.5\, GeV/c^{2}}$ the Migdal effect and Bremsstrahlung signatures were evaluated and lead to 90\% CL cross section limits of ${\rm 1.4\times 10^{-35}\, cm^{2}}$ and ${\rm 1.1\times 10^{-33}\, cm^{2}}$ respectively.
Published: 2022
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14. Searching for neutrinos from solar flares across solar cycles 23 and 24 with the Super-Kamiokande detector

Author: Okamoto, K., Abe, K., Hayato, Y., Hiraide, K., Hosokawa, K., Ieki, K., Ikeda, M., Kameda, J., Kanemura, Y., Kaneshima, Y., Kataoka, Y., Kashiwagi, Y., Miki, S., Mine, S., Miura, M., Moriyama, S., Nagao, Y., Nakahata, M., Nakano, Y., Nakayama, S., Noguchi, Y., Sato, K., Sekiya, H., Shimizu, K., Shiozawa, M., Shiba, H., Sonoda, Y., Suzuki, Y., Takeda, A., Takemoto, Y., Takenaka, A., Tanaka, H., Watanabe, S., Yano, T., 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., Kearns, E., Raaf, J. L., Wan, L., Wester, T., Bian, J., Griskevich, N. J., Kropp, W. R., Locke, S., Smy, M. B., Sobel, H. W., Takhistov, V., Yankelevich, A., Hill, J., Kim, J. Y., Lee, S. H., Lim, I. T., Moon, D. H., Park, R. G., Bodur, B., Scholberg, K., Walter, C. W., Beauchene, A., Bernard, L., Coffani, A., Drapier, O., Hedri, S. El, Giampaolo, A., Mueller, Th. A., Santos, A. D., Paganini, P., Quilain, B., Ishizuka, T., Nakamura, T., Jang, J. S., Learned, J. G., Choi, K., Cao, S., Anthony, L. H. V., Martin, D., Scott, M., Sztuc, A. A., Uchida, Y., Berardi, V., Catanesi, M. G., Radicioni, E., Calabria, N. F., Machado, L. N., De Rosa, G., Collazuol, G., Iacob, F., Lamoureux, M., Mattiazzi, M., Ludovici, L., Gonin, M., Pronost, G., Fujisawa, C., Maekawa, Y., Nishimura, Y., Friend, M., Hasegawa, T., Ishida, T., Kobayashi, T., Jakkapu, M., Matsubara, T., Nakadaira, T., Nakamura, K., Oyama, Y., Sakashita, K., Sekiguchi, T., Tsukamoto, T., Bhuiyan, N., Boschi, T., Burton, G. T., Di Lodovico, F., Gao, J., Goldsack, A., Katori, T., Migenda, J., Taani, M., Xie, Z., Zsoldos, S., Kotsar, Y., Ozaki, H., Suzuki, A. T., Takeuchi, Y., Yamamoto, S., Bronner, C., Feng, J., Kikawa, T., Mori, M., Nakaya, T., Wendell, R. A., Yasutome, K., Jenkins, S. J., McCauley, N., Mehta, P., Tarrant, A., 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., Vilela, C., Wilking, M. J., Yanagisawa, C., Harada, M., Ishino, H., Ito, S., Kitagawa, H., Koshio, Y., Ma, W., Nakanishi, F., Piplani, N., Sakai, S., Barr, G., Barrow, D., Cook, L., Samani, S., Wark, D., Holin, A., Nova, F., Yang, J. Y., Fannon, J. E. P., Malek, M., McElwee, J. M., Stone, O., Thiesse, M. D., Thompson, L. F., Okazawa, H., Kim, S. B., Kwon, E., Seo, J. W., Yu, I., Ichikawa, A. K., Nakamura, K. D., Tairafune, S., Nishijima, K., Koshiba, M., Iwamoto, K., Nakagiri, K., Nakajima, Y., Shima, S., Taniuchi, N., Yokoyama, M., Martens, K., de Perio, P., Vagins, M. R., Kuze, M., Izumiyama, S., Inomoto, M., Ishitsuka, M., Ito, H., Kinoshita, T., Matsumoto, R., Ommura, Y., Shigeta, N., Shinoki, M., Suganuma, T., Yamauchi, K., Martin, J. F., Tanaka, H. A., Towstego, T., Akutsu, R., Gaur, R., Gousy-Leblanc, V., Hartz, M., Konaka, A., Li, X., Prouse, N. W., Chen, S., Xu, B. D., Zhang, B., Posiadala-Zezula, M., Boyd, S. B., Hadley, D., Nicholson, M., O'Flaherty, M., Richards, B., Ali, A., Jamieson, B., Walker, J., Marti, Ll., Minamino, A., Pintaudi, G., Sano, S., Sasaki, R., Suzuki, S., and Wada, K.
Subjects: Astrophysics - Solar and Stellar Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, High Energy Physics - Experiment, Physics - Space Physics
Abstract: Neutrinos associated with solar flares (solar-flare neutrinos) provide information on particle acceleration mechanisms during the impulsive phase of solar flares. We searched using the Super-Kamiokande detector for neutrinos from solar flares that occurred during solar cycles $23$ and $24$, including the largest solar flare (X28.0) on November 4th, 2003. In order to minimize the background rate we searched for neutrino interactions within narrow time windows coincident with $\gamma$-rays and soft X-rays recorded by satellites. In addition, we performed the first attempt to search for solar-flare neutrinos from solar flares on the invisible side of the Sun by using the emission time of coronal mass ejections (CMEs). By selecting twenty powerful solar flares above X5.0 on the visible side and eight CMEs whose emission speed exceeds $2000$ $\mathrm{km \, s^{-1}}$ on the invisible side from 1996 to 2018, we found two (six) neutrino events coincident with solar flares occurring on the visible (invisible) side of the Sun, with a typical background rate of $0.10$ ($0.62$) events per flare in the MeV-GeV energy range. No significant solar-flare neutrino signal above the estimated background rate was observed. As a result we set the following upper limit on neutrino fluence at the Earth $\mathit{\Phi}<1.1\times10^{6}$ $\mathrm{cm^{-2}}$ at the $90\%$ confidence level for the largest solar flare. The resulting fluence limits allow us to constrain some of the theoretical models for solar-flare neutrino emission., Comment: 36 pages, 18 figures, 9 tables (Figure 12 was replaced because it was incorrect in version 1.)
Published: 2022

15. Search for Cosmic-ray Boosted Sub-GeV Dark Matter using Recoil Protons at Super-Kamiokande

Author: Collaboration, The Super-Kamiokande, 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., 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., Kearns, E., Raaf, J. L., Wan, L., Wester, T., Bian, J., Griskevich, N. J., Kropp, W. R., Locke, S., Smy, M. B., Sobel, H. W., Takhistov, V., Yankelevich, A., Hill, J., Park, R. G., Bodur, B., Scholberg, K., Walter, C. W., Bernard, L., Coffani, A., Drapier, O., Hedri, S. El, Giampaolo, A., Mueller, Th. A., Santos, A. D., Paganini, P., Quilain, B., Ishizuka, T., Nakamura, T., Jang, J. S., Learned, J. G., Choi, K., Cao, S., Anthony, L. H. V., Martin, D., Scott, M., Sztuc, A. A., Uchida, Y., Berardi, V., Catanesi, M. G., Radicioni, E., Calabria, N. F., Machado, L. N., De Rosa, G., Collazuol, G., Iacob, F., Lamoureux, M., Mattiazzi, M., Ludovici, L., Gonin, M., Pronost, G., Fujisawa, C., Maekawa, Y., Nishimura, Y., Friend, M., Hasegawa, T., Ishida, T., Kobayashi, T., Jakkapu, M., 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., 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., 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., Martens, K., de Perio, P., Vagins, M. R., Kuze, M., Izumiyama, S., Inomoto, M., Ishitsuka, M., Ito, H., Kinoshita, T., Matsumoto, R., Ommura, Y., Shigeta, N., Shinoki, M., Suganuma, T., Yamauchi, K., Martin, J. F., Tanaka, H. A., Towstego, T., Akutsu, R., Gousy-Leblanc, V., Hartz, M., Konaka, A., Prouse, N. W., Chen, S., Xu, B. D., Zhang, B., Posiadala-Zezula, M., Hadley, D., Nicholson, M., O'Flaherty, M., Richards, B., Ali, A., Jamieson, B., Marti, Ll., Minamino, A., Pintaudi, G., Sano, S., Suzuki, S., and Wada, K.
Subjects: High Energy Physics - Experiment
Abstract: We report a search for cosmic-ray boosted dark matter with protons using the 0.37 megaton$\times$years data collected at Super-Kamiokande experiment during the 1996-2018 period (SKI-IV phase). We searched for an excess of proton recoils above the atmospheric neutrino background from the vicinity of the Galactic Center. No such excess is observed, and limits are calculated for two reference models of dark matter with either a constant interaction cross-section or through a scalar mediator. This is the first experimental search for boosted dark matter with hadrons using directional information. The results present the most stringent limits on cosmic-ray boosted dark matter and exclude the dark matter-nucleon elastic scattering cross-section between $10^{-33}\text{ cm}^{2}$ and $10^{-27}\text{ cm}^{2}$ for dark matter mass from 10 MeV/$c^2$ to 1 GeV/$c^2$., Comment: With 1-page appendix. A bug was found in July 2023. This version is updated to match the erratum
Published: 2022
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16. Neutron Tagging following Atmospheric Neutrino Events in a Water Cherenkov Detector

Author: Abe, K., Haga, Y., Hayato, Y., Hiraide, K., Ieki, K., Ikeda, M., Imaizumi, S., Iyogi, K., Kameda, J., Kanemura, Y., Kataoka, Y., Kato, Y., Kishimoto, Y., Miki, S., Mine, S., Miura, M., Mochizuki, T., Moriyama, S., Nagao, Y., Nakahata, M., Nakajima, T., Nakano, Y., Nakayama, S., Okada, T., Okamoto, K., Orii, A., Sato, K., Sekiya, H., Shiozawa, M., Sonoda, Y., Suzuki, Y., Takeda, A., Takemoto, Y., Takenaka, A., Tanaka, H., Tasaka, S., Tomura, T., Ueno, K., Watanabe, S., Yano, T., Yokozawa, T., Han, S., Irvine, T., Kajita, T., Kametani, I., Kaneyuki, K., Lee, K. P., McLachlan, T., Okumura, K., Richard, E., Tashiro, T., Wang, R., Xia, J., Megias, G. D., Bravo-Berguño, D., Labarga, L., Zaldivar, B., Goldhaber, M., Blaszczyk, F. d. M., Gustafson, J., Kachulis, C., Kearns, E., Raaf, J. L., Stone, J. L., Sulak, L. R., Sussman, S., Wan, L., Wester, T., Pointon, B. W., Bian, J., Carminati, G., Elnimr, M., Griskevich, N. J., Kropp, W. R., Locke, S., Renshaw, A., Smy, M. B., Sobel, H. W., Takhistov, V., Weatherly, P., Ganezer, K. S., Hartfiel, B. L., Hill, J., Keig, W. E., Hong, N., Kim, J. Y., Lim, I. T., Park, R. G., Akiri, T., Bodur, B., Himmel, A., Li, Z., O'Sullivan, E., Scholberg, K., Walter, C. W., Wongjirad, T., Bernard, L., Coffani, A., Drapier, O., Hedri, S. El, Giampaolo, A., Imber, J., Mueller, Th. A., Paganini, P., Quilain, B., Ishizuka, T., Nakamura, T., Jang, J. S., Choi, K., Learned, J. G., Matsuno, S., Smith, S. N., Amey, J., Anthony, L. H. V., Litchfield, R. P., Ma, W. Y., Marin, D., Sztuc, A. A., Uchida, Y., Wascko, M. O., Berardi, V., Catanesi, M. G., Intonti, R. A., Radicioni, E., Calabria, N. F., De Rosa, G., Machado, L. N., Collazuol, G., Iacob, F., Lamoureux, M., Ospina, N., Ludovici, L., Gonin, M., Pronost, G., Maekawa, Y., Nishimura, Y., Cao, S., Friend, M., Hasegawa, T., Ishida, T., Ishii, T., Jakkapu, M., Kobayashi, T., Matsubara, T., Nakadaira, T., Nakamura, K., Oyama, Y., Sakashita, K., Sekiguchi, T., Tsukamoto, T., Boschi, T., Di Lodovico, F., Migenda, J., Sedgwick, S. Molina, Taani, M., Zsoldos, S., Abe, KE., Hasegawa, M., Isobe, Y., Kotsar, Y., Miyabe, H., Ozaki, H., Shiozawa, T., Sugimoto, T., Suzuki, A. T., Takeuchi, Y., Yamamoto, S., Ali, A., Ashida, Y., Bronner, C., Feng, J., Hayashino, T., Hiraki, T., Hirota, S., Huang, K., Jiang, M., Kikawa, T., Mori, M., Murakami, A., Nakamura, KE., Nakaya, T., Patel, N. D., Suzuki, K., Takahashi, S., Tateishi, K., Wendell, R. A., Yasutome, K., Fernandez, P., McCauley, N., Mehta, P., Pritchard, A., Tsui, K. M., Fukuda, Y., Itow, Y., Menjo, H., Mitsuka, G., Murase, M., Muto, F., Niwa, T., Tsukada, T. Suzuki M., Frankiewicz, K., Mijakowski, P., Hignight, J., Jiang, J., Jung, C. K., Li, X., Palomino, J. L., Santucci, G., Vilela, C., Wilking, M. J., Yanagisawa, C., Fukuda, D., Hagiwara, K., Harada, M., Horai, T., Ishino, H., Ito, S., Kayano, T., Kibayashi, A., Kitagawa, H., Koshio, Y., Ma, W., Mori, T., Nagata, H., Piplani, N., Sakai, S., Sakuda, M., Takahira, Y., Xu, C., Yamaguchi, R., Kuno, Y., Barr, G., Barrow, D., Cook, L., Goldsack, A., Samani, S., Simpson, C., Wark, D., Nova, F., Tacik, R., Yang, J. Y., Cole, A., Jenkins, S. J., Malek, M., McElwee, J. M., Stone, O., Thiesse, M. D., Thompson, L. F., Okazawa, H., Choi, Y., Kim, S. B., Yu, I., Ichikawa, A. K., Ito, K., Nishijima, K., Calland, R. G., de Perio, P., Martens, K., Murdoch, M., Vagins, M. R., Koshiba, M., Totsuka, Y., Iwamoto, K., Nakajima, Y., Ogawa, N., Suda, Y., Yokoyama, M., Hamabe, D., Izumiyama, S., Kuze, M., Okajima, Y., Tanaka, M., Yoshida, T., Inomoto, M., Ishitsuka, M., Ito, H., Matsumoto, R., Ohta, K., Shinoki, M., Martin, J. F., Nantais, C. M., Tanaka, H. A., Towstego, T., Akutsu, R., Hartz, M., Konaka, A., Prouse, N. W., Chen, S., Xu, B. D., Zhang, Y., Berkman, S., Tobayama, S., Connolly, K., Wilkes, R. J., Posiadala-Zezula, M., Hadley, D., Richards, B., Jamieson, B., Walker, J., Marti, Ll., Minamino, A., Pintaudi, G., Sano, S., and Sasaki, R.
Subjects: High Energy Physics - Experiment, Astrophysics - Instrumentation and Methods for Astrophysics, Physics - Instrumentation and Detectors
Abstract: We present the development of neutron-tagging techniques in Super-Kamiokande IV using a neural network analysis. The detection efficiency of neutron capture on hydrogen is estimated to be 26%, with a mis-tag rate of 0.016 per neutrino event. The uncertainty of the tagging efficiency is estimated to be 9.0%. Measurement of the tagging efficiency with data from an Americium-Beryllium calibration agrees with this value within 10%. The tagging procedure was performed on 3,244.4 days of SK-IV atmospheric neutrino data, identifying 18,091 neutrons in 26,473 neutrino events. The fitted neutron capture lifetime was measured as 218 \pm 9 \mu s.
Published: 2022
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17. Search for proton decay via $p\rightarrow \mu^+K^0$ in 0.37 megaton-years exposure of Super-Kamiokande

Author: Collaboration, Super-Kamiokande, Matsumoto, R., 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., 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., Kearns, E., Raaf, J. L., Wan, L., Wester, T., Bian, J., Griskevich, N. J., Kropp, W. R., Locke, S., Smy, M. B., Sobel, H. W., Takhistov, V., Yankelevich, A., Hill, J., Kim, J. Y., Lim, I. T., Park, R. G., Bodur, B., Scholberg, K., Walter, C. W., Bernard, L., Coffani, A., Drapier, O., Hedri, S. El, Giampaolo, A., Mueller, Th. A., Santos, A. D., Paganini, P., Quilain, B., Ishizuka, T., Nakamura, T., Jang, J. S., Learned, J. G., Choi, K., Cao, S., Anthony, L. H. V., Martin, D., Scott, M., Sztuc, A. A., Uchida, Y., Berardi, V., Catanesi, M. G., Radicioni, E., Calabria, N. F., Machado, L. N., De Rosa, G., Collazuol, G., Iacob, F., Lamoureux, M., Mattiazzi, M., Ludovici, L., Gonin, M., Pronost, G., Fujisawa, C., Maekawa, Y., Nishimura, Y., Friend, M., Hasegawa, T., Ishida, T., Kobayashi, T., Jakkapu, M., 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., Xie, Z., Zsoldos, S., Kotsar, Y., Ozaki, H., Suzuki, A. T., Takeuchi, Y., Yamamoto, 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., Tarrant, A., Fukuda, Y., Itow, Y., Menjo, H., Ninomiya, K., Lagoda, J., Lakshmi, S. M., Mandal, M., Mijakowski, P., Prabhu, Y. S., Zalipska, J., Jiang, M. Jia 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., Holin, A., Nova, F., Yang, J. Y., Malek, M., McElwee, J. M., Stone, O., Thiesse, M. D., Thompson, L. F., Okazawa, H., Kim, S. B., Kwon, E., Seo, J. W., Yu, I., Ichikawa, A. K., Nakamura, K. D., Tairafune, S., Nishijima, K., Koshiba, M., Iwamoto, K., Nakagiri, K., Nakajima, Y., Shima, S., Taniuchi, N., Yokoyama, M., Martens, K., de Perio, P., Vagins, M. R., Kuze, M., Izumiyama, S., Inomoto, M., Ishitsuka, M., Ito, H., Kinoshita, T., Ommura, Y., Shigeta, N., Shinoki, M., Suganuma, T., Yamauchi, K., Martin, J. F., Tanaka, H. A., Towstego, T., Akutsu, R., Gousy-Leblanc, V., Hartz, M., Konaka, A., Li, X., Prouse, N. W., Chen, S., Xu, B. D., Zhang, B., Posiadala-Zezula, M., Boyd, S. B., Hadley, D., Nicholson, M., O'Flaherty, M., Richards, B., Ali, A., Jamieson, B., Marti, Ll., Minamino, A., Pintaudi, G., Sano, S., Suzuki, S., and Wada, K.
Subjects: High Energy Physics - Experiment
Abstract: We searched for proton decay via $p\to\mu^+K^0$ in 0.37\,Mton$\cdot$years of data collected between 1996 and 2018 from the Super-Kamiokande water Cherenkov experiment. The selection criteria were defined separately for $K^0_S$ and $K^0_L$ channels. No significant event excess has been observed. As a result of this analysis, which extends the previous search by an additional 0.2\,Mton$\cdot$years of exposure and uses an improved event reconstruction, we set a lower limit of $3.6\times10^{33}$ years on the proton lifetime., Comment: 13 pages, 11 figures
Published: 2022

18. Search for supernova bursts in Super-Kamiokande IV

Author: collaboration, The Super-Kamiokande, Mori, M., Abe, K., Hayato, Y., Hiraide, K., Ieki, K., Ikeda, M., Imaizumi, S., Kameda, J., Kanemura, Y., Kaneshima, R., Kashiwagi, Y., Kataoka, Y., Miki, S., Mine, S., Miura, M., Moriyama, S., Nagao, Y., Nakahata, M., Nakano, Y., Nakayama, S., Noguchi, Y., Okada, T., Okamoto, K., Orii, A., Sato, K., Sekiya, H., Shiba, H., Shimizu, K., Shiozawa, M., Sonoda, Y., Suzuki, Y., Takeda, A., Takemoto, Y., Takenaka, A., Tanaka, H., Tomiya, T., Watanabe, S., Yano, T., Yoshida, S., Han, S., Kajita, T., Okumura, K., Tashiro, T., Wang, X., Xia, J., Megias, G. D., Bravo-Berguno, D., Fernandez, P., Labarga, L., Ospina, N., Zaldivar, B., Zsoldos, S., Pointon, B. W., Blaszczyk, F. d. M., Kearns, E., Raaf, J. L., Stone, J. L., Wan, L., Wester, T., Bian, J., Griskevich, N. J., Kropp, W. R., Locke, S., Smy, M. B., Sobel, H. W., Takhistov, V., Yankelevich, Hill, J., Kim, J. Y., Lim, I. T., Park, R. G., Bodur, B., Scholberg, K., Walter, C. W., Bernard, L., Coffani, A., Drapier, O., Hedri, S. El, Giampaolo, A., Mueller, Th. A., Paganini, P., Quilain, B., Santos, A. D., Ishizuka, T., Nakamura, T., Jang, J. S., Learned, J. G., Anthony, L. H. V., Martin, D., Scott, M., Sztuc, A. A., Uchida, Y., Berardi, V., Catanesi, M. G., Radicioni, E., Calabria, N. F., Machado, L. N., De Rosa, G., Collazuol, G., Iacob, F., Lamoureux, M., Mattiazzi, M., Ludovici, L., Gonin, M., Pronost, G., Maekawa, Y., Nishimura, Y., Fujisawa, C., Friend, M., Hasegawa, T., Ishida, T., Kobayashi, T., Jakkapu, M., Matsubara, T., Nakadaira, T., Nakamura, K., Oyama, Y., Sakashita, K., Sekiguchi, T., Tsukamoto, T., Ozaki, H., Shiozawa, T., Suzuki, A. T., Takeuchi, Y., Yamamoto, S., Kotsar, Y., Ashida, Y., Bronner, C., Feng, J., Hirota, S., Kikawa, T., Nakaya, T., Wendell, R. A., Yasutome, K., McCauley, N., Mehta, P., Tsui, K. M., Fukuda, Y., Itow, Y., Menjo, H., Ninomiya, K., Niwa, T., Tsukada, M., Lagoda, J., Lakshmi, S. M., Mijakowski, P., Zalipska, J., Mandal, M., Prabhu, Y. S., Jiang, J., Jung, C. K., Vilela, C., Wilking, M. J., Yanagisawa, C., Jia, M., Hagiwara, K., Harada, M., Horai, T., Ishino, H., Ito, S., Kitagawa, H., Koshio, Y., Ma, W., Nakanishi, F., Piplani, N., Sakai, S., Barr, G., Barrow, D., Cook, L., Samani, S., Wark, D., Nova, F., Boschi, T., Gao, J., Goldsack, A., Katori, T., Di Lodovico, F., Migenda, J., Taani, M., Yang, J. Y., Jenkins, S. J., Malek, M., McElwee, J. M., Stone, O., Thiesse, M. D., Thompson, L. F., Okazawa, H., Kim, S. B., Seo, J. W., Yu, I., Nishijima, K., Koshiba, M., Nakagiri, K., Nakajima, Y., Iwamoto, K., Taniuchi, N., Yokoyama, M., Martens, K., de Perio, P., Vagins, M. R., Kuze, M., Izumiyama, S., Yoshida, T., Inomoto, M., Ishitsuka, M., Ito, H., Kinoshita, T., Matsumoto, R., Ohta, K., Ommura, Y., Shigeta, N., Shinoki, M., Suganuma, T., Yamauchi, K., Martin, J. F., Tanaka, H. A., Towstego, T., Akutsu, R., Gousy-Leblanc, V., Hartz, M., Konaka, A., Prouse, N. W., Chen, S., Xu, B. D., Zhang, B., Posiadala-Zezula, M., Hadley, D., Nicholson, M., Flaherty, M. O', Richards, B., Ali, A., Jamieson, B., Walker, J., Marti, Ll., Minamino, A., Pintaudi, G., Sasaki, R., Sano, S., Suzuki, S., Wada, K., Cao, S., Ichikawa, A., Nakamura, K. D., and Tairafun, S.
Subjects: Astrophysics - High Energy Astrophysical Phenomena, High Energy Physics - Experiment
Abstract: Super-Kamiokande has been searching for neutrino bursts characteristic of core-collapse supernovae continuously, in real time, since the start of operations in 1996. The present work focuses on detecting more distant supernovae whose event rate may be too small to trigger in real time, but may be identified using an offline approach. The analysis of data collected from 2008 to 2018 found no evidence of distant supernovae bursts. This establishes an upper limit of 0.29 year$^{-1}$ on the rate of core-collapse supernovae out to 100 kpc at 90% C.L.. For supernovae that fail to explode and collapse directly to black holes the limit reaches to 300 kpc.
Published: 2022
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19. Pre-Supernova Alert System for Super-Kamiokande

Author: Collaboration, 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., Hedri, S. El, Giampaolo, A., Mueller, Th. 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., Xu, B. D., Zhang, B., Posiadala-Zezula, M., Hadley, D., Nicholson, M., O'Flaherty, M., Richards, B., Ali, A., Jamieson, B., Marti, Ll., Minamino, A., Pintaudi, G., Sano, S., Suzuki, S., and Wada, K.
Subjects: High Energy Physics - Experiment, Astrophysics - High Energy Astrophysical Phenomena, Physics - Instrumentation and Detectors
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 nine hours in advance of the core-collapse itself., Comment: 20 pages
Published: 2022
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20. Search for neutrinoless quadruple beta decay of $^{136}$Xe in XMASS-I

Author: XMASS Collaboration, Abe, K., Hiraide, K., Ichimura, K., Kato, N., Kishimoto, Y., Kobayashi, K., Kobayashi, M., Moriyama, S., Nakahata, M., Sato, K., Sekiya, H., Suzuki, T., Takeda, A., Tasaka, S., Yamashita, M., Yang, B. S., Kim, N. Y., Kim, Y. D., Kim, Y. H., Ishii, R., Itow, Y., Kanzawa, K., Masuda, K., Martens, K., Mason, A., Suzuki, Y., Miuchi, K., Takeuchi, Y., Lee, K. B., Lee, M. K., Fukuda, Y., Ogawa, H., Nishijima, K., Fushimi, K., Xu, B. D., and Nakamura, S.
Subjects: Nuclear Experiment, High Energy Physics - Experiment, Physics - Instrumentation and Detectors
Abstract: A search for the neutrinoless quadruple beta decay of $^{136}$Xe was conducted with the liquid-xenon detector XMASS-I using $\rm 327\; kg \times 800.0 \; days$ of the exposure. The pulse shape discrimination based on the scintillation decay time constant which distinguishes $\gamma$-rays including the signal and $\beta$-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 $\times$ 10$^{24}$ years at 90$\%$ confidence level. This is the first experimental constraint of the neutrinoless quadruple beta decay of $^{136}$Xe.
Published: 2022
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21. Testing Non-Standard Interactions Between Solar Neutrinos and Quarks with Super-Kamiokande

Author: Collaboration, Super-Kamiokande, Weatherly, P., Abe, K., Bronner, C., Hayato, Y., Hiraide, K., Ikeda, M., Iyogi, K., Kameda, J., Kanemura, Y., Kataoka, Y., Kato, Y., Kishimoto, Y., Miki, S., Miura, M., Moriyama, S., Mochizuki, T., Nakahata, M., Nakano, Y., Nakayama, S., Okada, T., Okamoto, K., Orii, A., Pronost, G., Sato, K., Sekiya, H., Shiozawa, M., Sonoda, Y., Suzuki, Y., Takeda, A., Takemoto, Y., Takenaka, A., Tanaka, H., Tasaka, S., Wang, X., Watanabe, S., Yano, T., Han, S., Kajita, T., Kaneyuki, K., Okumura, K., Tashiro, T., Wang, R., Xia, J., Megias, G. D., Labarga, L., Zaldivar, B., Pointon, B. W., Blaszczyk, F. d. M., Kachulis, C., Kearns, E., Raaf, J. L., Stone, J. L., Sulak, L. R., Sussman, S., Wan, L., Wester, T., Berkman, S., Tobayama, S., Bian, J., Elnimr, M., Griskevich, N. J., Kropp, W. R., Locke, S., Mine, S., Smy, M. B., Sobel, H. W., Takhistov, V., Yankelevich, A., Ganezer, K. S., Hill, J., Kim, J. Y., Lim, I. T., Park, R. G., Bodur, B., Li, Z., Scholberg, K., Walter, C. W., Bernard, L., Coffani, A., Drapier, O., Giampaolo, A., Hedri, S. El, Imber, J., Mueller, Th. A., Paganini, P., Quilain, B., Santos, A. D., Ishizuka, T., Nakamura, T., Jang, J. S., Learned, J. G., Matsuno, S., Cao, S., Amey, J., Anthony, L. H. V., Litchfield, R. P., Ma, W. Y., Martin, D., Scott, M., Sztuc, A. A., Uchida, Y., Wascko, M. O., Berardi, V., Catanesi, M. G., Intonti, R. A., Radicioni, E., Calabria, N. F., Machado, L. N., De Rosa, G., Collazuol, G., Iacob, F., Lamoureux, M., Mattiazzi, M., Ospina, N., Ludovici, L., Gonin, M., Maekawa, Y., Nishimura, Y., 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., Katori, T., Migenda, J., Taani, M., Zsoldos, S., Abe, KE., Hasegawa, M., Isobe, Y., Kotsar, Y., Miyabe, H., Ozaki, H., Sugimoto, T., Suzuki, A. T., Takeuchi, Y., Yamamoto, S., Ashida, Y., Feng, J., Hayashino, T., Hirota, S., Jiang, M., Kikawa, T., Mori, M., Nakaya, T., Wendell, R. A., Yasutome, K., Fernandez, P., McCauley, N., Mehta, P., Pritchard, A., Tsui, K. M., Fukuda, Y., Itow, Y., Menjo, H., Murase, M., Frankiewicz, K., Lagoda, J., Lakshmi, S. M., Mandal, M., Mijakowski, P., Prabhu, Y. S., Zalipska, J., Jia, M., Jiang, J., Jung, C. K., Li, X., Palomino, J. L., Santucci, G., Vilela, C., Wilking, M. J., Yanagisawa, C., Fukuda, D., Hagiwara, K., Harada, M., Ishino, H., Ito, S., Kitagawa, H., Koshio, Y., Ma, W., Sakai, S., Sakuda, M., Takahira, Y., Xu, C., Kuno, Y., Barr, G., Barrow, D., Cook, L., Goldsack, A., Samani, S., Simpson, C., Wark, D., Sedgwick, S. Molina, Tacik, R., Nova, F., Yang, J. Y., Jenkins, S. J., Malek, M., McElwee, J. M., Stone, O., Thiesse, M. D., Thompson, L. F., Okazawa, H., Choi, Y., Kim, S. B., Seo, J. W., Yu, I., Ichikawa, A., Nakamura, K. D., Nishijima, K., Koshiba, M., Iwamoto, K., Nakagiri, K., Nakajima, Y., Suda, Y., Taniuchi, N., Yokoyama, M., Martens, K., Murdoch, M., Vagins, M. R., Hamabe, D., Izumiyama, S., Kuze, M., Okajima, Y., Yoshida, T., Inomoto, M., Ishitsuka, M., Ito, H., Kinoshita, T., Matsumoto, R., Shinoki, M., Suganuma, T., Yonenaga, M., Martin, J. F., Nantais, C. M., Tanaka, H. A., Towstego, T., Akutsu, R., de Perio, P., Gousy-Leblanc, V., Hartz, M., Konaka, A., Prouse, N. W., Chen, S., Xu, B. D., Zhang, B., Posiadala-Zezula, M., Hadley, D., Nicholson, M., O'Flaherty, M., Richards, B., Ali, A., Jamieson, B., Giorgio, P., Marti, Ll., Minamino, A., Pintaudi, G., Sano, S., Sasaki, R., and Wada, K.
Subjects: High Energy Physics - Experiment, Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Solar and Stellar Astrophysics
Abstract: Non-Standard Interactions (NSI) between neutrinos and matter affect the neutrino flavor oscillations. Due to the high matter density in the core of the Sun, solar neutrinos are suited to probe these interactions. Using the $277$ kton-yr exposure of Super-Kamiokande to $^{8}$B solar neutrinos, we search for the presence of NSI. Our data favors the presence of NSI with down quarks at 1.8$\sigma$, and with up quarks at 1.6$\sigma$, with the best fit NSI parameters being ($\epsilon_{11}^{d},\epsilon_{12}^{d}$) = (-3.3, -3.1) for $d$-quarks and ($\epsilon_{11}^{u},\epsilon_{12}^{u}$) = (-2.5, -3.1) for $u$-quarks. After combining with data from the Sudbury Neutrino Observatory and Borexino, the significance increases by 0.1$\sigma$., Comment: Author: Pierce Weatherly 25 pages. To be submitted to Physical Review D
Published: 2022

22. New Methods and Simulations for Cosmogenic Induced Spallation Removal in Super-Kamiokande-IV

Author: Collaboration, Super-Kamiokande, Locke, S., Coffani, A., Abe, K., Bronner, C., Hayato, Y., Ikeda, M., Imaizumi, S., Ito, H., Kameda, J., Kataoka, Y., Miura, M., Moriyama, S., Nagao, Y., Nakahata, M., Nakajima, Y., Nakayama, S., Okada, T., Okamoto, K., Orii, A., Pronost, G., Sekiya, H., Shiozawa, M., Sonoda, Y., Suzuki, Y., Takeda, A., Takemoto, Y., Takenaka, A., Tanaka, H., Yano, T., Hirade, K., Kanemura, Y., Miki, S., Watabe, S., Han, S., Kajita, T., Okumura, K., Tashiro, T., Xia, J., Wang, X., Megias, G. D., Bravo-Berguño, D., Labarga, L., Marti, Ll., Zaldivar, B., Pointon, B. W., Blaszczyk, F. d. M., Kearns, E., Raaf, J. L., Stone, J. L., Wan, L., Wester, T., Bian, J., Griskevich, N. J., Kropp, W. R., Mine, S., Yankelevic, A., Smy, M. B., Sobel, H. W., Takhistov, V., Hill, J., Kim, J. Y., Lim, I. T., Park, R. G., Bodur, B., Scholberg, K., Walter, C. W., Bernard, L., Drapier, O., Hedri, S. El, Giampaolo, A., Gonin, M., Mueller, Th. A., Paganini, P., Quilain, B., Santos, A. D., Ishizuka, T., Nakamura, T., Jang, J. S., Learned, J. G., Anthony, L. H. V., Sztuc, A. A., Uchida, Y., Martin, D., Scott, M., Berardi, V., Catanesi, M. G., Radicioni, E., Calabria, N. F., Machado, L. N., De Rosa, G., Collazuol, G., Iacob, F., Lamoureux, M., Ospina, N., Mattiazzi, M., Ludovici, L., Nishimura, Y., Maewaka, Y., Cao, S., Friend, M., Hasegawa, T., Ishida, T., Kobayashi, T., Jakkapu, M., Matsubara, T., Nakadaira, T., Nakamura, K., Oyama, Y., Sakashita, K., Sekiguchi, T., Tsukamoto, T., Nakano, Y., Shiozawa, T., Suzuki, A. T., Takeuchi, Y., Yamamoto, S., Kotsar, Y., Ozaki, H., Ali, A., Ashida, Y., Feng, J., Hirota, S., Ichikawa, A. K., Kikawa, T., Mori, M., Nakaya, T., Wendell, R. A., Yasutome, K., Fernandez, P., McCauley, N., Mehta, P., Tsui, K. M., Fukuda, Y., Itow, Y., Menjo, H., Niwa, T., Sato, K., Tsukada, M., Mijakowski, P., Lagoda, J., Lakshmi, S. M., Zalipska, J., Jung, C. K., Vilela, C., Wilking, M. J., Yanagisawa, C., Jiang, J., Hagiwara, K., Harada, M., Horai, T., Ishino, H., Ito, S., Koshio, Y., Ma, W., Piplani, N., Sakai, S., Kitagawa, H., Barr, G., Barrow, D., Cook, L., Goldsack, A., Samani, S., Wark, D., Nova, F., Boschi, T., Di Lodovico, F., Taani, M., Zsoldos, S., Gao, J., Migenda, J., Yang, J. Y., Jenkins, S. J., Malek, M., McElwee, J. M., Stone, O., Thiesse, M. D., Thompson, L. F., Okazawa, H., Kim, S. B., Yu, I., Seo, J. W., Nishijima, K., Koshiba, M., Iwamoto, K., Ogawa, N., Yokoyama, M., Martens, K., Vagins, M. R., Nakagiri, K., Kuze, M., Izumiyama, S., Yoshida, T., Inomoto, M., Ishitsuka, M., Matsumoto, R., Ohta, K., Shinoki, M., Suganuma, T., Kinoshita, T., Martin, J. F., Tanaka, H. A., Towstego, T., Akutsu, R., Hartz, M., Konaka, A., de Perio, P., Prouse, N. W., Chen, S., Xu, B. D., Zhang, Y., Posiadala-Zezula, M., Richards, B., Jamieson, B., Walker, J., Minamino, A., Pintaudi, G., and Sasaki, R.
Subjects: High Energy Physics - Experiment, Astrophysics - High Energy Astrophysical Phenomena
Abstract: Radioactivity induced by cosmic muon spallation is a dominant source of backgrounds for $\mathcal{O}(10)~$MeV neutrino interactions in water Cherenkov detectors. In particular, it is crucial to reduce backgrounds to measure the solar neutrino spectrum and find neutrino interactions from distant supernovae. In this paper we introduce new techniques to locate muon-induced hadronic showers and efficiently reject spallation backgrounds. Applying these techniques to the solar neutrino analysis with an exposure of $2790\times22.5$~kton.day increases the signal efficiency by $12.6\%$, approximately corresponding to an additional year of detector running. Furthermore, we present the first spallation simulation at SK, where we model hadronic interactions using FLUKA. The agreement between the isotope yields and shower pattern in this simulation and in the data gives confidence in the accuracy of this simulation, and thus opens the door to use it to optimize muon spallation removal in new data with gadolinium-enhanced neutron capture detection.
Published: 2021

23. Diffuse Supernova Neutrino Background Search at Super-Kamiokande

Author: Collaboration, Super-Kamiokande, Abe, K., Bronner, C., Hayato, Y., Hiraide, K., Ikeda, M., Imaizumi, S., Kameda, J., Kanemura, Y., Kataoka, Y., Miki, S., Miura, M., Moriyama, S., Nagao, Y., Nakahata, M., Nakayama, S., Okada, T., Okamoto, K., Orii, A., Pronost, G., Sekiya, H., Shiozawa, M., Sonoda, Y., Suzuki, Y., Takeda, A., Takemoto, Y., Takenaka, A., Tanaka, H., Watanabe, S., Yano, T., Han, S., Kajita, T., Okumura, K., Tashiro, T., Xia, J., Megias, G. D., Bravo-Bergu, D., Labarga, L., Marti, Ll., Zaldivar, B., Pointon, B. W., Blaszczyk, F. d. M., Kearns, E., Raaf, J. L., Stone, J. L., Wan, L., Wester, T., Bian, J., Griskevich, N. J., Kropp, W. R., Locke, S., Mine, S., Smy, M. B., Sobel, H. W., Takhistov, V., Hill, J., Kim, J. Y., Lim, I. T., Park, R. G., Bodur, B., Scholberg, K., Walter, C. W., Cao, S., Bernard, L., Coffani, A., Drapier, O., Hedri, S. El, Giampaolo, A., Gonin, M., Mueller, Th. A., Paganini, P., Quilain, B., Ishizuka, T., Nakamura, T., Jang, J. S., Learned, J. G., Anthony, L. H. V., Martin, D., Scott, M., Sztuc, A. A., Uchida, Y., Berardi, V., Catanesi, M. G., Radicioni, E., Calabria, N. F., Machado, L. N., De Rosa, G., Collazuol, G., Iacob, F., Lamoureux, M., Mattiazzi, M., Ospina, N., Ludovici, L., Maekawa, Y., Nishimura, Y., Friend, M., Hasegawa, T., Ishida, T., Kobayashi, T., Jakkapu, M., Matsubara, T., Nakadaira, T., Nakamura, K., Oyama, Y., Sakashita, K., Sekiguchi, T., Tsukamoto, T., Kotsar, Y., Nakano, Y., Ozaki, H., Shiozawa, T., Suzuki, A. T., Takeuchi, Y., Yamamoto, S., Ali, A., Ashida, Y., Feng, J., Hirota, S., Kikawa, T., Mori, M., Nakaya, T., Wendell, R. A., Yasutome, K., Fernandez, P., McCauley, N., Mehta, P., Tsui, K. M., Fukuda, Y., Itow, Y., Menjo, H., Niwa, T., Sato, K., Tsukada, M., Lagoda, J., Lakshmi, S. M., Mijakowski, P., Zalipska, J., Jiang, J., Jung, C. K., Vilela, C., Wilking, M. J., Yanagisawa, C., Hagiwara, K., Harada, M., Horai, T., Ishino, H., Ito, S., Kitagawa, H., Koshio, Y., Ma, W., Piplani, N., Sakai, S., Barr, G., Barrow, D., Cook, L., Goldsack, A., Samani, S., Wark, D., Nova, F., Boschi, T., Di Lodovico, F., Gao, J., Migenda, J., Taani, M., Zsoldos, S., Yang, J. Y., Jenkins, S. J., Malek, M., McElwee, J. M., Stone, O., Thiesse, M. D., Thompson, L. F., Okazawa, H., Kim, S. B., Seo, J. W., Yu, I., Nishijima, K., Koshiba, M., Iwamoto, K., Nakagiri, K., Nakajima, Y., Ogawa, N., Yokoyama, M., Martens, K., Vagins, M. R., Kuze, M., Izumiyama, S., Yoshida, T., Inomoto, M., Ishitsuka, M., Ito, H., Kinoshita, T., Matsumoto, R., Ohta, K., Shinoki, M., Suganuma, T., Ichikawa, A. K., Martin, J. F., Tanaka, H. A., Towstego, T., Akutsu, R., Gousy-Leblanc, V., Hartz, M., Konaka, A., de Perio, P., Prouse, N. W., Chen, S., Xu, B. D., Zhang, Y., Posiadala-Zezula, M., Hadley, D., O'Flaherty, M., Richards, B., Jamieson, B., Walker, J., Minamino, A., Pintaudi, G., Sano, S., and Sasaki, R.
Subjects: Astrophysics - High Energy Astrophysical Phenomena, High Energy Physics - Experiment
Abstract: A new search for the diffuse supernova neutrino background (DSNB) flux has been conducted at Super-Kamiokande (SK), with a $22.5\times2970$-kton$\cdot$day exposure from its fourth operational phase IV. The new analysis improves on the existing background reduction techniques and systematic uncertainties and takes advantage of an improved neutron tagging algorithm to lower the energy threshold compared to the previous phases of SK. This allows for setting the world's most stringent upper limit on the extraterrestrial $\bar{\nu}_e$ flux, for neutrino energies below 31.3 MeV. The SK-IV results are combined with the ones from the first three phases of SK to perform a joint analysis using $22.5\times5823$ kton$\cdot$days of data. This analysis has the world's best sensitivity to the DSNB $\bar{\nu}_e$ flux, comparable to the predictions from various models. For neutrino energies larger than 17.3 MeV, the new combined $90\%$ C.L. upper limits on the DSNB $\bar{\nu}_e$ flux lie around $2.7$ cm$^{-2}$$\cdot$$\text{sec}^{-1}$, strongly disfavoring the most optimistic predictions. Finally, potentialities of the gadolinium phase of SK and the future Hyper-Kamiokande experiment are discussed., Comment: 42 pages, 37 figures, 14 tables
Published: 2021
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24. First Gadolinium Loading to Super-Kamiokande

Author: Abe, K., Bronner, C., Hayato, Y., Hiraide, K., Ikeda, M., Imaizumi, S., Kameda, J., Kanemura, Y., Kataoka, Y., Miki, S., Miura, M., Moriyama, S., Nagao, Y., Nakahata, M., Nakayama, S., Okada, T., Okamoto, K., Orii, A., Pronost, G., Sekiya, H., Shiozawa, M., Sonoda, Y., Suzuki, Y., Takeda, A., Takemoto, Y., Takenaka, A., Tanaka, H., Watanabe, S., Yano, T., Han, S., Kajita, T., Okumura, K., Tashiro, T., Xia, J., Megias, G. D., Bravo-Berguno, D., Labarga, L., Marti, Ll., Zaldivar, B., Pointon, B. W., Blaszczyk, F. d. M., Kearns, E., Raaf, J. L., Stone, J. L., Wan, L., Wester, T., Bian, J., Griskevich, N. J., Kropp, W. R., Locke, S., Mine, S., Smy, M. B., Sobel, H. W., Takhistov, V., Hill, J., Kim, J. Y., Lim, I. T., Park, R. G., Bodur, B., Scholberg, K., Walter, C. W., Bernard, L., Coffani, A., Drapier, O., Hedri, S. El, Giampaolo, A., Gonin, M., Mueller, Th. A., Paganini, P., Quilain, B., Ishizuka, T., Nakamura, T., Jang, J. S., Learned, J. G., Anthony, L. H. V., Martin, D., Scott, M., Sztuc, A. A., Uchida, Y., Cao, S., Berardi, V., Catanesi, M. G., Radicioni, E., Calabria, N. F., Machado, L. N., De Rosa, G., Collazuol, G., Iacob, F., Lamoureux, M., Mattiazzi, M., Ospina, N., Ludovici, L., Maekawa, Y., Nishimura, Y., Friend, M., Hasegawa, T., Ishida, T., Kobayashi, T., Jakkapu, M., Matsubara, T., Nakadaira, T., Nakamura, K., Oyama, Y., Sakashita, K., Sekiguchi, T., Tsukamoto, T., Boschi, T., Gao, J., Di Lodovico, F., Migenda, J., Taani, M., Zsoldos, S., Kotsar, Y., Nakano, Y., Ozaki, H., Shiozawa, T., Suzuki, A. T., Takeuchi, Y., Yamamoto, S., Ali, A., Ashida, Y., Feng, J., Hirota, S., Kikawa, T., Mori, M., Nakaya, T., Wendell, R. A., Yasutome, K., Fernandez, P., McCauley, N., Mehta, P., Tsui, K. M., Fukuda, Y., Itow, Y., Menjo, H., Niwa, T., Sato, K., Tsukada, M., Lagoda, J., Lakshmi, S. M., Mijakowski, P., Zalipska, J., Jiang, J., Jung, C. K., Vilela, C., Wilking, M. J., Yanagisawa, C., Hagiwara, K., Harada, M., Horai, T., Ishino, H., Ito, S., Kitagawa, F., Koshio, Y., Ma, W., Piplani, N., Sakai, S., Barr, G., Barrow, D., Cook, L., Goldsack, A., Samani, S., Wark, D., Nova, F., Yang, J. Y., Jenkins, S. J., 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., Nishijima, K., Koshiba, M., Iwamoto, K., Nakajima, Y., Ogawa, N., Yokoyama, M., Martens, K., Vagins, M. R., Kuze, M., Izumiyama, S., Yoshida, T., Inomoto, M., Ishitsuka, M., Ito, H., Kinoshita, T., Matsumoto, R., Ohta, K., Shinoki, M., Suganuma, T., Martin, J. F., Tanaka, H. A., Towstego, T., Akutsu, R., Hartz, M., Konaka, A., de Perio, P., Prouse, N. W., Chen, S., Xu, B. D., Posiadala-Zezula, M., Hadley, D., O'Flaherty, M., Richards, B., Jamieson, B., Walker, J., Minamino, A., Pintaudi, G., Sano, S., and Sasaki, R.
Subjects: Physics - Instrumentation and Detectors, Astrophysics - Instrumentation and Methods for Astrophysics
Abstract: In order to improve Super-Kamiokande's neutron detection efficiency and to thereby increase its sensitivity to the diffuse supernova neutrino background flux, 13 tons of $\rm Gd_2(\rm SO_4)_3\cdot \rm 8H_2O$ (gadolinium sulfate octahydrate) was dissolved into the detector's otherwise ultrapure water from July 14 to August 17, 2020, marking the start of the SK-Gd phase of operations. During the loading, water was continuously recirculated at a rate of 60 m$^3$/h, extracting water from the top of the detector and mixing it with concentrated $\rm Gd_2(\rm SO_4)_3\cdot \rm 8H_2O$ solution to create a 0.02% solution of the Gd compound before injecting it into the bottom of the detector. A clear boundary between the Gd-loaded and pure water was maintained through the loading, enabling monitoring of the loading itself and the spatial uniformity of the Gd concentration over the 35 days it took to reach the top of the detector. During the subsequent commissioning the recirculation rate was increased to 120 m$^3$/h, resulting in a constant and uniform distribution of Gd throughout the detector and water transparency equivalent to that of previous pure-water operation periods. Using an Am-Be neutron calibration source the mean neutron capture time was measured to be $115\pm1$ $\mu$s, which corresponds to a Gd concentration of $111\pm2$ ppm, as expected for this level of Gd loading. This paper describes changes made to the water circulation system for this detector upgrade, the Gd loading procedure, detector commissioning, and the first neutron calibration measurements in SK-Gd., Comment: 37 pages, 19 Figures, Accepted for publication in Nucl. Instrum. Meth. A
Published: 2021
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25. Search for neutrinos in coincidence with gravitational wave events from the LIGO-Virgo O3a Observing Run with the Super-Kamiokande detector

Author: collaboration, The Super-Kamiokande, Abe, K., Bronner, C., Hayato, Y., Ikeda, M., Imaizumi, S., Kameda, J., Kanemura, Y., Kataoka, Y., Miki, S., Miura, M., Moriyama, S., Nagao, Y., Nakahata, M., Nakayama, S., Okada, T., Okamoto, K., Orii, A., Pronost, G., Sekiya, H., Shiozawa, M., Sonoda, Y., Suzuki, Y., Takeda, A., Takemoto, Y., Takenaka, A., Tanaka, H., Watanabe, S., Yano, T., Han, S., Kajita, T., Okumura, K., Tashiro, T., Wang, R., Xia, J., Megias, G. D., Bravo-Berguño, D., Labarga, L., Marti, Ll., Zaldivar, B., Pointon, B. W., Blaszczyk, F. d. M., Kearns, E., Raaf, J. L., Stone, J. L., Wan, L., Wester, T., Bian, J., Griskevich, N. J., Kropp, W. R., Locke, S., Mine, S., Smy, M. B., Sobel, H. W., Takhistov, V., Weatherly, P., Hill, J., Kim, J. Y., Lim, I. T., Park, R. G., Bodur, B., Scholberg, K., Walter, C. W., Bernard, L., Coffani, A., Drapier, O., Hedri, S. El, Giampaolo, A., Gonin, M., Mueller, Th. A., Paganini, P., Quilain, B., Ishizuka, T., Nakamura, T., Jang, J. S., Learned, J. G., Anthony, L. H. V., Martin, D. G. R., Sztuc, A. A., Uchida, Y., Berardi, V., Catanesi, M. G., Radicioni, E., Calabria, N. F., Machado, L. N., De Rosa, G., Collazuol, G., Iacob, F., Lamoureux, M., Ospina, N., Ludovici, L., Maekawa, Y., Nishimura, Y., Cao, S., Friend, M., Hasegawa, T., Ishida, T., Jakkapu, M., Kobayashi, T., Matsubara, T., Nakadaira, T., Nakamura, K., Oyama, Y., Sakashita, K., Sekiguchi, T., Tsukamoto, T., Kotsar, Y., Nakano, Y., Ozaki, H., Shiozawa, T., Suzuki, A. T., Takeuchi, Y., Yamamoto, S., Ali, A., Ashida, Y., Feng, J., Hirota, S., Kikawa, T., Mori, M., Nakaya, T., Wendell, R. A., Yasutome, K., Fernandez, P., McCauley, N., Mehta, P., Pritchard, A., Tsui, K. M., Fukuda, Y., Itow, Y., Menjo, H., Niwa, T., Sato, K., Tsukada, M., Mijakowski, P., Jiang, J., Jung, C. K., Vilela, C., Wilking, M. J., Yanagisawa, C., Hagiwara, K., Harada, M., Horai, T., Ishino, H., Ito, S., Koshio, Y., Kitagawa, H., Ma, W., Piplani, N., Sakai, S., Kuno, Y., Barr, G., Barrow, D., Cook, L., Goldsack, A., Samani, S., Simpson, C., Wark, D., Nova, F., Boschi, T., Di Lodovico, F., Migenda, J., Sedgwick, S. Molina, Taani, M., Zsoldos, S., Yang, J. Y., Jenkins, S. J., Malek, M., McElwee, J. M., Stone, O., Thiesse, M. D., Thompson, L. F., Okazawa, H., Kim, S. B., Yu, I., Nishijima, K., Koshiba, M., Nakajima, K. Iwamoto Y., Ogawa, N., Yokoyama, M., Martens, K., Vagins, M. R., Izumiyama, S., Kuze, M., Tanaka, M., Yoshida, T., Inomoto, M., Ishitsuka, M., Ito, H., Matsumoto, R., Ohta, K., Shinoki, M., Martin, J. F., Tanaka, H. A., Towstego, T., Akutsu, R., Hartz, M., Konaka, A., de Perio, P., Prouse, N. W., Chen, S., Xu, B. D., Posiadala-Zezula, M., Hadley, D., Richards, B., Jamieson, B., Walker, J., Minamino, A., Pintaudi, G., Sano, S., Sasaki, R., Ichikawa, A. K., and Nakamura, K. D.
Subjects: Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Instrumentation and Methods for Astrophysics, High Energy Physics - Experiment
Abstract: The Super-Kamiokande detector can be used to search for neutrinos in time coincidence with gravitational waves detected by the LIGO-Virgo Collaboration (LVC). Both low-energy ($7-100$ MeV) and high-energy ($0.1-10^5$ GeV) samples were analyzed in order to cover a very wide neutrino spectrum. Follow-ups of 36 (out of 39) gravitational waves reported in the GWTC-2 catalog were examined; no significant excess above the background was observed, with 10 (24) observed neutrinos compared with 4.8 (25.0) expected events in the high-energy (low-energy) samples. A statistical approach was used to compute the significance of potential coincidences. For each observation, p-values were estimated using neutrino direction and LVC sky map ; the most significant event (GW190602_175927) is associated with a post-trial p-value of $7.8\%$ ($1.4\sigma$). Additionally, flux limits were computed independently for each sample and by combining the samples. The energy emitted as neutrinos by the identified gravitational wave sources was constrained, both for given flavors and for all-flavors assuming equipartition between the different flavors, independently for each trigger and by combining sources of the same nature., Comment: 16 pages, 5 figures. v2: adding corrections from The Astrophysical Journal review
Published: 2021
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26. Search for Tens of MeV Neutrinos associated with Gamma-Ray Bursts in Super-Kamiokande

Author: Collaboration, The Super-Kamiokande, Orii, A., Abe, K., Bronner, C., Hayato, Y., Ikeda, M., Imaizumi, S., Ito, H., Kameda, J., Kataoka, Y., Kato, Y., Kishimoto, Y., Miura, M., Moriyama, S., Mochizuki, T., Nagao, Y., Nakahata, M., Nakajima, Y., Nakayama, S., Okada, T., Okamoto, K., Pronost, G., Sekiya, H., Shiozawa, M., Sonoda, Y., Suzuki, Y., Takeda, A., Takemoto, Y., Takenaka, A., Tanaka, H., Yano, T., Han, S., Kajita, T., Okumura, K., Tashiro, T., Wang, R., Xia, J., Megias, G. D., Bravo-Berguno, D., Labarga, L., Marti, Ll., Zaldivar, B., Blaszczyk, F. d. M., Kearns, E., Raaf, J. L., Stone, J. L., Wan, L., Wester, T., Pointon, B. W., Bian, J., Griskevich, N. J., Kropp, W. R., Locke, S., Mine, S., Smy, M. B., Sobel, H. W., Takhistov, V., Weatherly, P., Ganezer, K. S., Hill, J., Kim, J. Y., Lim, I. T., Park, R. G., Bodur, B., Scholberg, K., Walter, C. W., Bernard, L., Coffani, A., Drapier, O., Hedri, S. El, Giampaolo, A., Gonin, M., Mueller, Th. A., Paganini, P., Quilain, B., Ishizuka, T., Nakamura, T., Jang, J. S., Learned, J. G., Matsuno, S., Anthony, L. H. V., Litchfield, R. P., Sztuc, A. A., Uchida, Y., Berardi, V., Catanesi, M. G., Radicioni, E., Calabria, N. F., Machado, L. N., De Rosa, G., Collazuol, G., Iacob, F., Lamoureux, M., Ospina, N., Ludovici, L., Nishimura, Y., Cao, S., Friend, M., Hasegawa, T., Ishida, T., Kobayashi, T., Jakkapu, M., Matsubara, T., Nakadaira, T., Nakamura, K., Oyama, Y., Sakashita, K., Sekiguchi, T., Tsukamoto, T., Boschi, T., Di Lodovico, F., Sedgwick, S. Molina, Taani, M., Zsoldos, S., Hasegawa, M., Isobe, Y., Miyabe, H., Nakano, Y., Shiozawa, T., Sugimoto, T., Suzuki, A. T., Takeuchi, Y., Yamamoto, S., Ali, A., Ashida, Y., Feng, J., Hirota, S., Jiang, M., Ichikawa, A. K., Kikawa, T., Mori, M., Nakamura, KE., Nakaya, T., Wendell, R. A., Yasutome, K., Fernandez, P., McCauley, N., Mehta, P., Pritchard, A., Tsui, K. M., Fukuda, Y., Itow, Y., Menjo, H., Niwa, T., Sato, K., Tsukada, M., Mijakowski, P., Frankiewicz, K., Jung, C. K., Vilela, C., Wilking, M. J., Yanagisawa, C., Fukuda, D., Harada, M., Hagiwara, K., Horai, T., Ishino, H., Ito, S., Koshio, Y., Ma, W., Piplani, N., Sakai, S., Sakuda, M., Takahira, Y., Xu, C., Kuno, Y., Barr, G., Barrow, D., Cook, L., Goldsack, A., Samani, S., Simpson, C., Wark, D., Nova, F., Yang, J. Y., Jenkins, S. J., Malek, M., McElwee, J. M., Stone, O., Thiesse, M. D., Thompson, L. F., Okazawa, H., Choi, Y., Kim, S. B., Yu, I., Nishijima, K., Koshiba, M., Iwamoto, K., Ogawa, N., Yokoyama, M., Martens, K., Vagins, M. R., Izumiyama, S., Kuze, M., Tanaka, M., Yoshida, T., Inomoto, M., Ishitsuka, M., Matsumoto, R., Ohta, K., Shinoki, M., Martin, J. F., Nantais, C. M., Tanaka, H. A., Towstego, T., Akutsu, R., Hartz, M., Konaka, A., de Perio, P., Prouse, N. W., Chen, S., Xu, B. D., Posiadala-Zezula, M., Richards, B., Jamieson, B., Walker, J., Minamino, A., Pintaudi, G., and Sasaki, R.
Subjects: Astrophysics - High Energy Astrophysical Phenomena, High Energy Physics - Experiment
Abstract: A search for neutrinos produced in coincidence with Gamma-Ray Bursts(GRB) was conducted with the Super-Kamiokande (SK) detector. Between December 2008 and March 2017, the Gamma-ray Coordinates Network recorded 2208 GRBs that occurred during normal SK operation. Several time windows around each GRB were used to search for coincident neutrino events. No statistically significant signal in excess of the estimated backgrounds was detected. The $\bar\nu_e$ fluence in the range from 8 MeV to 100 MeV in positron total energy for $\bar\nu_e+p\rightarrow e^{+}+n$ was found to be less than $\rm 5.07\times10^5$ cm$^{-2}$ per GRB in 90\% C.L. Upper bounds on the fluence as a function of neutrino energy were also obtained., Comment: 29 pages, 16 figures, 5 tables, accepted by PTEP
Published: 2021

27. Search for solar electron anti-neutrinos due to spin-flavor precession in the Sun with Super-Kamiokande-IV

Author: Collaboration, Super-Kamiokande, Abe, K., Bronner, C., Hayato, Y., Ikeda, M., Imaizumi, S., Ito, H., Kameda, J., Kataoka, Y., Miura, M., Moriyama, S., Nagao, Y., Nakahata, M., Nakajima, Y., Nakayama, S., Okada, T., Okamoto, K., Orii, A., Pronost, G., Sekiya, H., Shiozawa, M., Sonoda, Y., Suzuki, Y., Takeda, A., Takemoto, Y., Takenaka, A., Tanaka, H., Yano, T., Akutsu, R., Han, S., Kajita, T., Okumura, K., Tashiro, T., Wang, R., Xia, J., Bravo-Berguño, D., Labarga, L., Marti, Ll., Zaldivar, B., Blaszczyk, F. d. M., Kearns, E., Raaf, J. L., Stone, J. L., Wan, L., Wester, T., Pointin, B. W., Bian, J., Griskevich, N. J., Kropp, W. R., Locke, S., Mine, S., Smy, M. B., Sobel, H. W., Takhistov, V., Weatherly, P., Hill, J., Kim, J. Y., Lim, I. T., Park, R. G., Bodur, B., Scholberg, K., Walter, C. W., Bernard, L., Coffani, A., Drapier, O., Hedri, S. El, Giampaolo, A., Gonin, M., Mueller, Th. A., Paganini, P., Quilain, B., Ishizuka, T., Nakamura, T., Jang, J. S., Learned, J. G., Anthony, L. H. V., Sztuc, A. A., Uchida, Y., Berardi, V., Catanesi, M. G., Radicioni, E., Calabria, N. F., Machado, L. N., De Rosa, G., Collazuol, G., Iacob, F., Lamoureux, M., Ospina, N., Ludovici, L., Nishimura, Y., Cao, S., Friend, M., Hasegawa, T., Ishida, T., Jakkapu, M., Kobayashi, T., Matsubara, T., Nakadaira, T., Nakamura, K., Oyama, Y., Sakashita, K., Sekiguchi, T., Tsukamoto, T., Nakano, Y., Shiozawa, T., Suzuki, A. T., Takeuchi, Y., Yamamoto, S., Ali, A., Ashida, Y., Feng, J., Hirota, S., Ichikawa, A. K., Kikawa, T., Mori, M., Nakaya, T., Wendell, R. A., Yasutome, Y., Fernandez, P., McCauley, N., Mehta, P., Pritchard, A., Tsui, K. M., Fukuda, Y., Itow, Y., Menjo, H., Niwa, T., Sato, K., Tsukada, M., Mijakowski, P., Jung, C. K., Vilela, C., Wilking, M. J., Yanagisawa, C., Harada, M., Hagiwara, K., Horai, T., Ishino, H., Ito, S., Koshio, Y., Ma, W., Piplani, N., Sakai, S., Kuno, Y., Barr, G., Barrow, D., Cook, L., Goldsack, A., Samani, S., Simpson, C., Wark, D., Nova, F., Boschi, T., Di Lodovico, F., Taani, M., Migenda, J., Sedgwick, S. Molina, Zsoldos, S., Yang, J. Y., Jenkins, S. J., Malek, M., McElwee, J. M., Stone, O., Thiesse, M. D., Thompson, L. F., Okazawa, H., Kim, S. B., Yu, I., Nishijima, K., Koshiba, M., Iwamoto, K., Ogawa, N., Yokoyama, M., Martens, K., Vagins, M. R., Izumiyama, S., Kuze, M., Tanaka, M., Yoshida, T., Inomoto, M., Ishitsuka, M., Matsumoto, R., Ohta, K., Shinoki, M., Martin, J. F., Tanaka, H. A., Towstego, T., Hartz, M., Konaka, A., de Perio, P., Prouse, N. W., Chen, S., Xu, B. D., Richards, B., Jamieson, B., Walker, J., Minamino, A., Pintaudi, G., Sasaki, R., and Posiadala-Zezula, M.
Subjects: High Energy Physics - Experiment, Physics - Instrumentation and Detectors
Abstract: Due to a very low production rate of electron anti-neutrinos ($\bar{\nu}_e$) via nuclear fusion in the Sun, a flux of solar $\bar{\nu}_e$ is unexpected. An appearance of $\bar{\nu}_e$ in solar neutrino flux opens a new window for the new physics beyond the standard model. In particular, a spin-flavor precession process is expected to convert an electron neutrino into an electron anti-neutrino (${\nu_e\to\bar{\nu}_e}$) when neutrino has a finite magnetic moment. In this work, we have searched for solar $\bar{\nu}_e$ in the Super-Kamiokande experiment, using neutron tagging to identify their inverse beta decay signature. We identified 78 $\bar{\nu}_e$ candidates for neutrino energies of 9.3 to 17.3 MeV in 2970.1 live days with a fiducial volume of 22.5 kiloton water (183.0 kton$\cdot$year exposure). The energy spectrum has been consistent with background predictions and we thus derived a 90% confidence level upper limit of ${4.7\times10^{-4}}$ on the $\nu_e\to\bar{\nu}_e$ conversion probability in the Sun. We used this result to evaluate the sensitivity of future experiments, notably the Super-Kamiokande Gadolinium (SK-Gd) upgrade., Comment: 16 pages, 10 figures, 7 tables
Published: 2020
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28. Neutron-Antineutron Oscillation Search using a 0.37 Megaton$\cdot$Year Exposure of Super-Kamiokande

Author: Collaboration, Super-Kamiokande, Abe, K., Bronner, C., Hayato, Y., Ikeda, M., Imaizumi, S., Ito, H., Kameda, J., Kataoka, Y., Miura, M., Moriyama, S., Nagao, Y., Nakahata, M., Nakajima, Y., Nakayama, S., Okada, T., Okamoto, K., Orii, A., Pronost, G., Sekiya, H., Shiozawa, M., Sonoda, Y., Suzuki, Y., Takeda, A., Takemoto, Y., Takenaka, A., Tanaka, H., Yano, T., Akutsu, R., Han, S., Kajita, T., Okumura, K., Tashiro, T., Wang, R., Xia, J., Bravo-Berguño, D., Labarga, L., Marti, Ll., Zaldivar, B., Blaszczyk, F. d. M., Kearns, E., Gustafson, J. D., Raaf, J. L., Stone, J. L., Wan, L., Wester, T., Bian, J., Griskevich, N. J., Kropp, W. R., Locke, S., Mine, S., Smy, M. B., Sobel, H. W., Takhistov, V., Weatherly, P., Hill, J., Kim, J. Y., Lim, I. T., Park, R. G., Bodur, B., Scholberg, K., Walter, C. W., Coffani, A., Drapier, O., Hedri, S. El, Giampaolo, A., Gonin, M., Mueller, Th. A., Paganini, P., Quilain, B., Ishizuka, T., Nakamura, T., Jang, J. S., Learned, J. G., Anthony, L. H. V., Sztuc, A. A., Uchida, Y., Berardi, V., Catanesi, M. G., Radicioni, E., Calabria, N. F., Machado, L. N., De Rosa, G., Collazuol, G., Iacob, F., Lamoureux, M., Ospina, N., Ludovici, L., Nishimura, Y., Cao, S., Friend, M., Hasegawa, T., Ishida, T., Kobayashi, T., Matsubara, T., Nakadaira, T., Jakkapu, M., Nakamura, K., Oyama, Y., Sakashita, K., Sekiguchi, T., Tsukamoto, T., Nakano, Y., Shiozawa, T., Suzuki, A. T., Takeuchi, Y., Yamamoto, S., Ali, A., Ashida, Y., Feng, J., Hirota, S., Ichikawa, A. K., Kikawa, T., Mori, M., Nakaya, T., Wendell, R. A., Yasutome, K., Fernandez, P., McCauley, N., Mehta, P., Pritchard, A., Tsui, K. M., Fukuda, Y., Itow, Y., Menjo, H., Niwa, T., Sato, K., Tsukada, M., Mijakowski, P., Posiadala-Zezula, M., Jung, C. K., Vilela, C., Wilking, M. J., Yanagisawa, C., Harada, M., Hagiwara, K., Horai, T., Ishino, H., Ito, S., Koshio, Y., Ma, W., Piplani, N., Sakai, S., Kuno, Y., Barr, G., Barrow, D., Cook, L., Goldsack, A., Samani, S., Simpson, C., Wark, D., Nova, F., Boschi, T., Di Lodovico, F., Sedgwick, S. Molina, Taani, M., Zsoldos, S., Yang, J. Y., Jenkins, S. J., McElwee, J. M., Thiesse, M. D., Thompson, L. F., Malek, M., Stone, O., Okazawa, H., Kim, S. B., Yu, I., Nishijima, K., Koshiba, M., Ogawa, N., Iwamoto, K., Yokoyama, M., Martens, K., Vagins, M. R., Kuze, M., Izumiyama, S., Tanaka, M., Yoshida, T., Inomoto, M., Ishitsuka, M., Matsumoto, R., Ohta, K., Shinoki, M., Martin, J. F., Tanaka, H. A., Towstego, T., Hartz, M., Konaka, A., de Perio, P., Prouse, N. W., Pointon, B. W., Chen, S., Xu, B. D., Richards, B., Jamieson, B., Walker, J., Minamino, A., Pintaudi, G., and Sasaki, R.
Subjects: High Energy Physics - Experiment
Abstract: As a baryon number violating process with $\Delta B=2$, neutron-antineutron oscillation ($n\to\bar n$) provides a unique test of baryon number conservation. We have performed a search for $n\to\bar n$ oscillation with bound neutrons in Super-Kamiokande, with the full data set from its first four run periods, representing an exposure of 0.37~Mton-years. The search used a multivariate analysis trained on simulated $n\to\bar n$ events and atmospheric neutrino backgrounds and resulted in 11 candidate events with an expected background of 9.3 events. In the absence of statistically significant excess, we derived a lower limit on $\bar n$ appearance lifetime in $^{16}$O nuclei of $3.6\times{10}^{32}$ years and on the neutron-antineutron oscillation time of $\tau_{n\to\bar n} > 4.7\times10^{8}$~s at 90\% C.L..
Published: 2020
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29. Search for proton decay via $p\to e^+\pi^0$ and $p\to \mu^+\pi^0$ with an enlarged fiducial volume in Super-Kamiokande I-IV

Author: Collaboration, Super-Kamiokande, Takenaka, A., Abe, K., Bronner, C., Hayato, Y., Ikeda, M., Imaizumi, S., Ito, H., Kameda, J., Kataoka, Y., Kato, Y., Kishimoto, Y., Marti, Ll., Miura, M., Moriyama, S., Mochizuki, T., Nagao, Y., Nakahata, M., Nakajima, Y., Nakayama, S., Okada, T., Okamoto, K., Orii, A., Pronost, G., Sekiya, H., Shiozawa, M., Sonoda, Y., Suzuki, Y., Takeda, A., Takemoto, Y., Tanaka, H., Yano, T., Akutsu, R., Han, S., Kajita, T., Okumura, K., Tashiro, T., Wang, R., Xia, J., Bravo-Berguno, D., Labarga, L., Fernandez, P., Zaldivar, B., Blaszczyk, F. d. M., Kearns, E., Raaf, J. L., Stone, J. L., Wan, L., Wester, T., Pointon, B. W., Bian, J., Griskevich, N. J., Kropp, W. R., Locke, S., Mine, S., Smy, M. B., Sobel, H. W., Takhistov, V., Weatherly, P., Ganezer, K. S., Hill, J., Kim, J. Y., Lim, I. T., Park, R. G., Bodur, B., Scholberg, K., Walter, C. W., Coffani, A., Drapier, O., Hedri, S. El, Giampaolo, A., Gonin, M., Mueller, Th. A., Paganini, P., Quilain, B., Ishizuka, T., Nakamura, T., Jang, J. S., Learned, J. G., Matsuno, S., Anthony, L. H. V., Litchfield, R. P., Sztuc, A. A., Uchida, Y., Berardi, V., Catanesi, M. G., Radicioni, E., Calabria, N. F., Machado, L. N., De Rosa, G., Collazuol, G., Iacob, F., Lamoureux, M., Ospina, N., Ludovici, L., Nishimura, Y., Cao, S., Friend, M., Hasegawa, T., Ishida, T., Jakkapu, M., Kobayashi, T., Matsubara, T., Nakadaira, T., Nakamura, K., Oyama, Y., Sakashita, K., Sekiguchi, T., Tsukamoto, T., Hasegawa, M., Isobe, Y., Miyabe, H., Nakano, Y., Shiozawa, T., Sugimoto, T., Suzuki, A. T., Takeuchi, Y., Yamamoto, S., Ali, A., Ashida, Y., Feng, J., Hirota, S., Ichikawa, A. K., Jiang, M., Kikawa, T., Mori, M., Nakamura, KE., Nakaya, T., Wendell, R. A., Yasutome, K., McCauley, N., Mehta, P., Pritchard, A., Tsui, K. M., Fukuda, Y., Itow, Y., Menjo, H., Niwa, T., Sato, K., Taani, M., Tsukada, M., Mijakowski, P., Frankiewicz, K., Jung, C. K., Santucci, G., Vilela, C., Wilking, M. J., Yanagisawa, C., Fukuda, D., Harada, M., Hagiwara, K., Horai, T., Ishino, H., Ito, S., Koshio, Y., Ma, W., Piplani, N., Sakai, S., Sakuda, M., Takahira, Y., Xu, C., Kuno, Y., Barr, G., Barrow, D., Cook, L., Simpson, C., Wark, D., Nova, F., Boschi, T., Di Lodovico, F., Sedgwick, S. Molina, Zsoldos, S., Yang, J. Y., Jenkins, S. J., McElwee, J. M., Thiesse, M. D., Thompson, L. F., Okazawa, H., Choi, Y., Kim, S. B., Yu, I., Nishijima, K., Koshiba, M., Iwamoto, K., Ogawa, N., Yokoyama, M., Goldsack, A., Martens, K., Vagins, M. R., Kuze, M., Tanaka, M., Yoshida, T., Inomoto, M., Ishitsuka, M., Matsumoto, R., Ohta, K., Shinoki, M., Martin, J. F., Nantais, C. M., Tanaka, H. A., Towstego, T., Hartz, M., Konaka, A., de Perio, P., Prouse, N. W., Chen, S., Xu, B. D., Posiadala-Zezula, M., Richards, B., Jamieson, B., Walker, J., Minamino, A., Pintaudi, G., and Sasaki, R.
Subjects: High Energy Physics - Experiment
Abstract: We have searched for proton decay via $p\to e^+\pi^0$ and $p\to \mu^+\pi^0$ modes with the enlarged fiducial volume data of Super-Kamiokande from April 1996 to May 2018, which corresponds to 450 kton$\cdot$years exposure. We have accumulated about 25% more livetime and enlarged the fiducial volume of the Super-Kamiokande detector from 22.5 kton to 27.2 kton for this analysis, so that 144 kton$\cdot$years of data, including 78 kton$\cdot$years of additional fiducial volume data, has been newly analyzed. No candidates have been found for $p\to e^+\pi^0$ and one candidate remains for $p\to \mu^+\pi^0$ in the conventional 22.5 kton fiducial volume and it is consistent with the atmospheric neutrino background prediction. We set lower limits on the partial lifetime for each of these modes: $\tau/B(p\to e^+\pi^0) > 2.4 \times 10^{34}$ years and $\tau/B(p\to \mu^+\pi^0) > 1.6 \times 10^{34}$ years at 90% confidence level., Comment: 16 pages, 10 figures
Published: 2020
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30. Search for event bursts in XMASS-I associated with gravitational-wave events

Author: XMASS Collaboration, Abe, K., Hiraide, K., Ichimura, K., Kishimoto, Y., Kobayashi, K., Kobayashi, M., Moriyama, S., Nakahata, M., Ogawa, H., Sato, K., Sekiya, H., Suzuki, T., Takeda, A., Tasaka, S., Yamashita, M., Yang, B. S., Kim, N. Y., Kim, Y. D., Itow, Y., Kanzawa, K., Masuda, K., Martens, K., Suzuki, Y., Xu, B. D., Miuchi, K., Oka, N., Takeuchi, Y., Kim, Y. H., Lee, K. B., Lee, M. K., Fukuda, Y., Miyasaka, M., Nishijima, K., Fushimi, K., Kanzaki, G., and Nakamura, S.
Subjects: Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Instrumentation and Methods for Astrophysics, High Energy Physics - Experiment, Nuclear Experiment, Physics - Instrumentation and Detectors
Abstract: We performed a search for event bursts in the XMASS-I detector associated with 11 gravitational-wave events detected during LIGO/Virgo's O1 and O2 periods. Simple and loose cuts were applied to the data collected in the full 832 kg xenon volume around the detection time of each gravitational-wave event. The data were divided into four energy regions ranging from keV to MeV. Without assuming any particular burst models, we looked for event bursts in sliding windows with various time width from 0.02 to 10 s. The search was conducted in a time window between $-$400 and $+$10,000 s from each gravitational-wave event. For the binary neutron star merger GW170817, no significant event burst was observed in the XMASS-I detector and we set 90% confidence level upper limits on neutrino fluence for the sum of all the neutrino flavors via coherent elastic neutrino-nucleus scattering. The obtained upper limit was (1.3-2.1)$\times 10^{11}$ cm$^{-2}$ under the assumption of a Fermi-Dirac spectrum with average neutrino energy of 20 MeV. The neutrino fluence limits for mono-energetic neutrinos in the energy range between 14 and 100 MeV were also calculated. Among the other 10 gravitational wave events detected as the binary black hole mergers, a burst candidate with a 3.0$\sigma$ significance was found at 1801.95-1803.95 s in the analysis for GW151012. However, no significant deviation from the background in the reconstructed energy and position distributions was found. Considering the additional look-elsewhere effect of analyzing the 11 GW events, the significance of finding such a burst candidate associated with any of them is 2.1$\sigma$., Comment: 8 pages, 12 figures
Published: 2020

31. Development of low-background photomultiplier tubes for liquid xenon detectors

Author: XMASS Collaboration, Abe, K., Chen, Y., Hiraide, K., Ichimura, K., Imaizumi, S., Kato, N., Kishimoto, Y., Kobayashi, K., Kobayashi, M., Moriyama, S., Nakahata, M., Sato, K., Sekiya, H., Suzuki, T., Takeda, A., Tasaka, S., Yamashita, M., Yang, B. S., Kim, N. Y., Kim, Y. D., Kim, Y. H., Ishii, R., Itow, Y., Kanzawa, K., Masuda, K., Martens, K., Mason, A., Suzuki, Y., Miuchi, K., Takeuchi, Y., Lee, K. B., Lee, M. K., Fukuda, Y., Ogawa, H., Nishijima, K., Fushimi, K., Xu, B. D., and Nakamuran, S.
Subjects: Physics - Instrumentation and Detectors
Abstract: We successfully developed a new photomultiplier tube (PMT) with a three-inch diameter, convex-shaped photocathode, R13111. Its prominent features include good performance and ultra-low radioactivity. The convex-shaped photocathode realized a large photon acceptance and good timing resolution. Low radioactivity was achieved by three factors: (1) the glass material was synthesized using low-radioactive-contamination material; (2) the photocathode was produced with $^{39}$K-enriched potassium; and (3) the purest grade of aluminum material was used for the vacuum seal. As a result each R13111 PMT contains only about 0.4 mBq of $^{226}$Ra, less than 2 mBq of $^{238}$U, 0.3 mBq of $^{228}$Ra, 2 mBq of $^{40}$K and 0.2 mBq of $^{60}$Co. We also examined and resolved the intrinsic leakage of Xe gas into PMTs that was observed in several older models. We thus succeeded in developing a PMT that has low background, large angular acceptance with high collection efficiency, good timing resolution, and long-term stable operation. These features are highly desirable for experiments searching for rare events beyond the standard model, such as dark matter particle interactions and neutrinoless double beta decay events.
Published: 2020
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32. Search for exotic neutrino-electron interactions using solar neutrinos in XMASS-I

Author: XMASS collaboration, Abe, K., Chen, Y., Hiraide, K., Ichimura, K., Imaizumi, S., Kato, N., Kobayashi, K., Kobayashi, M., Moriyama, S., Nakahata, M., Sato, K., Sekiya, H., Suzuki, T., Takeda, A., Tasaka, S., Yamashita, M., Yang, B. S., Kim, N. Y., Kim, Y. D., Kim, Y. H., Ishii, R., Itow, Y., Kanzawa, K., Martens, K., Mason, A., Suzuki, Y., Miuchi, K., Takeuchi, Y., Lee, K. B., Lee, M. K., Fukuda, Y., Ogawa, H., Kishimoto, Y., Nishijima, K., Fushimi, K., Xu, B. D., and Nakamura, S.
Subjects: High Energy Physics - Experiment, Astrophysics - High Energy Astrophysical Phenomena
Abstract: We have searched for exotic neutrino-electron interactions that could be produced by a neutrino millicharge, by a neutrino magnetic moment, or by dark photons using solar neutrinos in the XMASS-I liquid xenon detector. We observed no significant signals in 711 days of data. We obtain an upper limit for neutrino millicharge of 5.4$\times$10$^{-12} e$ at 90\% confidence level assuming all three species of neutrino have common millicharge. We also set flavor dependent limits assuming the respective neutrino flavor is the only one carrying a millicharge, $7.3 \times 10^{-12} e$ for $\nu_e$, $1.1 \times 10^{-11} e$ for $\nu_{\mu}$, and $1.1 \times 10^{-11} e$ for $\nu_{\tau}$. These limits are the most stringent yet obtained from direct measurements. We also obtain an upper limit for the neutrino magnetic moment of 1.8$\times$10$^{-10}$ Bohr magnetons. In addition, we obtain upper limits for the coupling constant of dark photons in the $U(1)_{B-L}$ model of 1.3$\times$10$^{-6}$ if the dark photon mass is 1$\times 10^{-3}$ MeV$/c^{2}$, and 8.8$\times$10$^{-5}$ if it is 10 MeV$/c^{2}$.
Published: 2020
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33. Indirect Search for Dark Matter from the Galactic Center and Halo with the Super-Kamiokande Detector

Author: Collaboration, Super-Kamiokande, Abe, K., Bronner, C., Haga, Y., Hayato, Y., Ikeda, M., Imaizumi, S., Ito, H., Iyogi, K., Kameda, J., Kataoka, Y., Kato, Y., Kishimoto, Y., Marti, Ll., Miura, M., Moriyama, S., Mochizuki, T., Nagao, Y., Nakahata, M., Nakajima, Y., Nakajima, T., Nakayama, S., Okada, T., Okamoto, K., Orii, A., Pronost, G., Sekiya, H., Shiozawa, M., Sonoda, Y., Takeda, A., Takenaka, A., Tanaka, H., Tasaka, S., Tomura, T., Ueno, K., Yano, T., Yokozawa, T., Akutsu, R., Han, S., Irvine, T., Kajita, T., Kametani, I., Lee, K. P., McLachlan, T., Okumura, K., Richard, E., Tashiro, T., Wang, R., Xia, J., Bravo-Berguño, D., Labarga, L., Fernandez, P., Blaszczyk, F. d. M., Gustafson, J., Kachulis, C., Kearns, E., Raaf, J. L., Stone, J. L., Sulak, L. R., Sussman, S., Wan, L., Wester, T., Berkman, S., Tobayama, S., Bian, J., Carminati, G., Elnimr, M., Griskevich, N. J., Kropp, W. R., Locke, S., Mine, S., Renshaw, A., Smy, M. B., Sobel, H. W., Takhistov, V., Weatherly, P., Hartfiel, B. L., Hill, J., Keig, W. E., Hong, N., Kim, J. Y., Lim, I. T., Park, R. G., Akiri, T., Bodur, B., Himmel, A., Li, Z., O'Sullivan, E., Scholberg, K., Walter, C. W., Wongjirad, T., Coffani, A., Drapier, O., Hedri, S. El, Giampaolo, A., Gonin, M., Imber, J., Mueller, Th. A., Paganini, P., Quilain, B., Ishizuka, T., Nakamura, T., Jang, J. S., Choi, K., Learned, J. G., Matsuno, S., Smith, S. N., Amey, J., Anthony, L. H. V., Litchfield, R. P., Ma, W. Y., Sztuc, A. A., Uchida, Y., Wascko, M. O., Berardi, V., Catanesi, M. G., Intonti, R. A., Radicioni, E., Calabria, N. F., Machado, L. N., De Rosa, G., Collazuol, G., Iacob, F., Lamoureux, M., Ospina, N., Ludovici, L., Boschi, T., Di Lodovico, F., Sedgwick, S. Molina, Zsoldos, S., Nishimura, Y., Cao, S., Friend, M., Hasegawa, T., Ishida, T., Ishii, T., Kobayashi, T., Nakadaira, T., Nakamura, K., Oyama, Y., Sakashita, K., Sekiguchi, T., Tsukamoto, T., Abe, KE., Hasegawa, M., Isobe, Y., Miyabe, H., Nakano, Y., Shiozawa, T., Sugimoto, T., Suzuki, A. T., Takeuchi, Y., Yamamoto, S., Ali, A., Ashida, Y., Hayashino, T., Hiraki, T., Hirota, S., Huang, K., Ieki, K., Jiang, M., Kikawa, T., Mori, M., Murakami, A., Nakamura, KE., Nakaya, T., Patel, N. D., Suzuki, K., Takahashi, S., Tateishi, K., Wendell, R. A., McCauley, N., Mehta, P., Pritchard, A., Tsui, K. M., Fukuda, Y., Itow, Y., Menjo, H., Mitsuka, G., Murase, M., Muto, F., Niwa, T., Sato, K., Suzuki, T., Taani, M., Tsukada, z M., Mijakowski, P., Frankiewicz, K., Hignight, J., Jung, C. K., Li, X., Palomino, J. L., Santucci, G., Vilela, C., Wilking, M. J., Yanagisawa, C., Fukuda, D., Hagiwara, K., Harada, M., Horai, T., Ishino, H., Ito, S., Kayano, T., Kibayashi, A., Koshio, Y., Ma, W., Mori, T., Nagata, H., Piplani, N., Sakuda, M., Seiya, S., Takahira, Y., Xu, C., Yamaguchi, R., Kuno, Y., Barr, G., Barrow, D., Cook, L., Simpson, C., Wark, D., Nova, F., Tacik, R., Yang, J. Y., Cole, A., Jenkins, S. J., McElwee, J., Thiesse, M., Thompson, L., Okazawa, H., Kim, S. B., Choi, Y., Ito, K., Nishijima, K., Iwamoto, K., Koshiba, M., Suda, Y., Yokoyama, M., Calland, R. G., Goldsack, A., Martens, K., Murdoch, M., Suzuki, Y., Vagins, M. R., Hamabe, D., Kuze, M., Okajima, Y., Tanaka, M., Yoshida, T., Inomoto, M., Ishitsuka, M., Matsumoto, R., Ohta, K., Shinoki, M., Martin, J. F., Nantais, C. M., Tanaka, H. A., Towstego, T., Hartz, M., Konaka, A., de Perio, P., Prouse, N. W., Chen, S., Xu, B. D., Zhang, Y., Richards, B., Connolly, K., Wilkes, R. J., Jamieson, B., Walker, J., Giorgio, P., Minamino, A., and Pintaudi, G.
Subjects: High Energy Physics - Experiment
Abstract: We present a search for an excess of neutrino interactions due to dark matter in the form of Weakly Interacting Massive Particles (WIMPs) annihilating in the galactic center or halo based on the data set of Super-Kamiokande-I, -II, -III and -IV taken from 1996 to 2016. We model the neutrino flux, energy, and flavor distributions assuming WIMP self-annihilation is dominant to $\nu \overline{\nu}$, $\mu^+\mu^-$, $b\overline{b}$, or $W^+W^-$. The excess is in comparison to atmospheric neutrino interactions which are modeled in detail and fit to data. Limits on the self-annihilation cross section $\langle \sigma_{A} V \rangle$ are derived for WIMP masses in the range 1 GeV to 10 TeV, reaching as low as $9.6 \times10^{-23}$ cm$^3$ s$^{-1}$ for 5 GeV WIMPs in $b\bar b$ mode and $1.2 \times10^{-24}$ cm$^3$ s$^{-1}$ for 1 GeV WIMPs in $\nu \bar \nu$ mode. The obtained sensitivity of the Super-Kamiokande detector to WIMP masses below several tens of GeV is the best among similar indirect searches to date., Comment: 13 pages, 12 figures, Submitted to Phys. Rev. D
Published: 2020
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34. Search for proton decay into three charged leptons in 0.37 megaton-years exposure of the Super-Kamiokande

Author: Collaboration, Super-Kamiokande, Tanaka, M., Abe, K., Bronner, C., Hayato, Y., Ikeda, M., Imaizumi, S., Ito, H., Kameda, J., Kataoka, Y., Kato, Y., Kishimoto, Y., Marti, Ll., Miura, M., Moriyama, S., Mochizuki, T., Nakahata, M., Nakajima, Y., Nakayama, S., Okada, T., Okamoto, K., Orii, A., Pronost, G., Sekiya, H., Shiozawa, M., Sonoda, Y., Takeda, A., Takenaka, A., Tanaka, H., Yano, T., Akutsu, R., Kajita, T., Okumura, K., Wang, R., Xia, J., Bravo-Berguño, D., Labarga, L., Fernandez, P., Blaszczyk, F. d. M., Kearns, E., Raaf, J. L., Stone, J. L., Wan, L., Wester, T., Bian, J., Griskevich, N. J., Kropp, W. R., Locke, S., Mine, S., Smy, M. B., Sobel, H. W., Takhistov, V., Weatherly, P., Hill, J., Kim, J. Y., Lim, I. T., Park, R. G., Bodur, B., Scholberg, K., Walter, C. W., Coffani, A., Drapier, O., Hedri, S. El, Gonin, M., Mueller, Th. A., Paganini, P., Ishizuka, T., Nakamura, T., Jang, J. S., Learned, J. G., Matsuno, S., Litchfield, R. P., Sztuc, A. A., Uchida, Y., Berardi, V., Catanesi, M. G., Radicioni, E., Calabria, N. F., De Rosa, G., Collazuol, G., Iacob, F., Ludovici, L., Nishimura, Y., Cao, S., Friend, M., Hasegawa, T., Ishida, T., Kobayashi, T., Nakadaira, T., Nakamura, K., Oyama, Y., Sakashita, K., Sekiguchi, T., Tsukamoto, T., Hasegawa, M., Isobe, Y., Miyabe, H., Nakano, Y., Shiozawa, T., Sugimoto, T., Suzuki, A. T., Takeuchi, Y., Ali, A., Ashida, Y., Hirota, S., Jiang, M., Kikawa, T., Mori, M., Nakamura, KE., Nakaya, T., Wendell, R. A., Anthony, L. H. V., McCauley, N., Mehta, P., Pritchard, A., Tsui, K. M., Fukuda, Y., Itow, Y., Niwa, T., Taani, M., Tsukada, M., Mijakowski, P., Frankiewicz, K., Jung, C. K., Vilela, C., Wilking, M. J., Yanagisawa, C., Fukuda, D., Harada, M., Hagiwara, K., Horai, T., Ishino, H., Ito, S., Koshio, Y., Sakuda, M., Takahira, Y., Xu, C., Kuno, Y., Barrow, D., Cook, L., Simpson, C., Wark, D., Nova, F., Boschi, T., Di Lodovico, F., Sedgwick, S. Molina, Zsoldos, S., Kim, S. B., Yang, J. Y., Thiesse, M., Thompson, L., Okazawa, H., Choi, Y., Nishijima, K., Koshiba, M., Yokoyama, M., Goldsack, A., Martens, K., Quilain, B., Suzuki, Y., Vagins, M. R., Kuze, M., Yoshida, T., Ishitsuka, M., Matsumoto, R., Ohta, K., Martin, J. F., Nantais, C. M., Tanaka, H. A., Towstego, T., Hartz, M., Konaka, A., de Perio, P., Prouse, N. W., Chen, S., Xu, B. D., Richards, B., Jamieson, B., Walker, J., Minamino, A., and Pintaudi, G.
Subjects: High Energy Physics - Experiment
Abstract: A search for proton decay into three charged leptons has been performed by using 0.37$\,$Mton$\cdot$years of data collected in Super-Kamiokande. All possible combinations of electrons, muons and their anti-particles consistent with charge conservation were considered as decay modes. No significant excess of events has been found over the background, and lower limits on the proton lifetime divided by the branching ratio have been obtained. The limits range between $9.2\times10^{33}$ to $3.4\times10^{34}$ years at 90$\,$% confidence level, improving by more than an order of magnitude upon limits from previous experiments. A first limit has been set for the $p\rightarrow\mu^-e^+e^+$ mode.
Published: 2020
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35. A measurement of the scintillation decay time constant of nuclear recoils in liquid xenon with the XMASS-I detector

Author: XMASS Collaboration, Abe, K., Hiraide, K., Ichimura, K., Kishimoto, Y., Kobayashi, K., Kobayashi, M., Moriyama, S., Nakahata, M., Ogawa, H., Sato, K., Sekiya, H., Suzuki, T., Takachio, O., Takeda, A., Tasaka, S., Yamashita, M., Yang, B. S., Kim, N. Y., Kim, Y. D., Itow, Y., Kanzawa, K., Masuda, K., Martens, K., Suzuki, Y., Xu, B. D., Miuchi, K., Oka, N., Takeuchi, Y., Kim, Y. H., Lee, K. B., Lee, M. K., Fukuda, Y., Miyasaka, M., Nishijima, K., Fushimi, K., Kanzaki, G., and Nakamura, S.
Subjects: Physics - Instrumentation and Detectors, High Energy Physics - Experiment, Nuclear Experiment
Abstract: We report an in-situ measurement of the nuclear recoil (NR) scintillation decay time constant in liquid xenon (LXe) using the XMASS-I detector at the Kamioka underground laboratory in Japan. XMASS-I is a large single-phase LXe scintillation detector whose purpose is the direct detection of dark matter via NR which can be induced by collisions between Weakly Interacting Massive Particles (WIMPs) and a xenon nucleus. The inner detector volume contains 832 kg of LXe. $^{252}$Cf was used as an external neutron source for irradiating the detector. The scintillation decay time constant of the resulting neutron induced NR was evaluated by comparing the observed photon detection times with Monte Carlo simulations. Fits to the decay time prefer two decay time components, one for each of the Xe$_{2}^{*}$ singlet and triplet states, with $\tau_{S}$ = 4.3$\pm$0.6 ns taken from prior research, $\tau_{T}$ was measured to be 26.9$^{+0.7}_{-1.1}$ ns with a singlet state fraction F$_{S}$ of 0.252$^{+0.027}_{-0.019}$.We also evaluated the performance of pulse shape discrimination between NR and electron recoil (ER) with the aim of reducing the electromagnetic background in WIMP searches. For a 50\% NR acceptance, the ER acceptance was 13.7${\pm}$1.0\% and 4.1${\pm}$0.7\% in the energy ranges of 5--10 keV$_{\rm ee}$ and 10--15 keV$_{\rm ee}$, respectively., Comment: 18 pages, 10 figures
Published: 2018
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36. Search for WIMP-$^{129}$Xe inelastic scattering with particle identification in XMASS-I

Author: XMASS Collaboration, Suzuki, T., Abe, K., Hiraide, K., Ichimura, K., Kishimoto, Y., Kobayashi, K., Kobayashi, M., Moriyama, S., Nakahata, M., Ogawa, H., Sato, K., Sekiya, H., Takeda, A., Tasaka, S., Yamashita, M., Yang, B. S., Kim, N. Y., Kim, Y. D., Itow, Y., Kanzawa, K., Masuda, K., Martens, K., Suzuki, Y., Xu, B. D., Miuchi, K., Oka, N., Takeuchi, Y., Kim, Y. H., Lee, K. B., Lee, M. K., Fukuda, Y., Miyasaka, M., Nishijima, K., Fushimi, K., Kanzaki, G., and Nakamura, S.
Subjects: Astrophysics - Cosmology and Nongalactic Astrophysics, High Energy Physics - Experiment, Nuclear Experiment
Abstract: A search for Weakly Interacting Massive Particles (WIMPs) was conducted with the single-phase liquid-xenon detector XMASS through inelastic scattering in which $^{129}$Xe nuclei were excited, using an exposure ($\rm 327\; kg \times 800.0 \; days$) 48 times larger than that of our previous study. The inelastic excitation sensitivity was improved by detailed evaluation of background, event classification based on scintillation timing that distinguished $\gamma$-rays and $\beta$-rays, and simultaneous fitting of the energy spectra of $\gamma$-like and $\beta$-like samples. No evidence of a WIMP signal was found. Thus, we set the upper limits of the inelastic channel cross section at 90\% confidence level, for example, $4.1\times 10^{-39} \;{\rm cm^2}$ for a $200\; {\rm GeV}/c^2$ WIMP. This result provides the most stringent limits on the SD WIMP-neutron interaction and is better by a factor of 7.7 at $200\;{\rm GeV}/c^2$ than the existing experimental limit., Comment: 8 pages, 10 figures
Published: 2018
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37. Search for sub-GeV dark matter by annual modulation using XMASS-I detector

Author: Kobayashi, M., Abe, K., Hiraide, K., Ichimura, K., Kishimoto, Y., Kobayashi, K., Moriyama, S., Nakahata, M., Ogawa, H., Sato, K., Sekiya, H., Suzuki, T., Takeda, A., Tasaka, S., Yamashita, M., Yang, B. S., Kim, N. Y., Kim, Y. D., Itow, Y., Kanzawa, K., Masuda, K., Martens, K., Suzuki, Y., Xu, B. D., Miuchi, K., Oka, N., Takeuchi, Y., Kim, Y. H., Lee, K. B., Lee, M. K., Fukuda, Y., Miyasaka, M., Nishijima, K., Fushimi, K., Kanzaki, G., and Nakamura, S.
Subjects: Astrophysics - Cosmology and Nongalactic Astrophysics, High Energy Physics - Experiment, Nuclear Experiment, Physics - Instrumentation and Detectors
Abstract: A search for dark matter (DM) with mass in the sub-GeV region (0.32-1 GeV) was conducted by looking for an annual modulation signal in XMASS, a single-phase liquid xenon detector. Inelastic nuclear scattering accompanied by bremsstrahlung emission was used to search down to an electron equivalent energy of 1 keV. The data used had a live time of 2.8 years (3.5 years in calendar time), resulting in a total exposure of 2.38 ton-years. No significant modulation signal was observed and 90% confidence level upper limits of $1.6 \times 10^{-33}$ cm$^2$ at 0.5 GeV was set for the DM-nucleon cross section. This is the first experimental result of a search for DM mediated by the bremsstrahlung effect. In addition, a search for DM with mass in the multi-GeV region (4-20 GeV) was conducted with a lower energy threshold than previous analysis of XMASS. Elastic nuclear scattering was used to search down to a nuclear recoil equivalent energy of 2.3 keV, and upper limits of 2.9 $\times$10$^{-42}$ cm$^2$ at 8 GeV was obtained., Comment: 7 pages, 5 figures
Published: 2018
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38. Development of low radioactivity photomultiplier tubes for the XMASS-I detector

Author: XMASS Collaboration, Abe, K., Hiraide, K., Ichimura, K., Kishimoto, Y., Kobayashi, K., Kobayashi, M., Moriyama, S., Nakahata, M., Norita, T., Ogawa, H., Sato, K., Sekiya, H., Takachio, O., Takeda, A., Tasaka, S., Yamashita, M., Yang, B. S., Kim, N. Y., Kim, Y. D., Itow, Y., Kanzawa, K., Kegasa, R., Masuda, K., Takiya, H., Fushimi, K., Kanzaki, G., Martens, K., Suzuki, Y., Xu, B. D., Fujita, R., Hosokawa, K., Miuchi, K., Oka, N., Takeuchi, Y., Kim, Y. H., Lee, K. B., Lee, M. K., Fukuda, Y., Miyasaka, M., Nishijima, K., and Nakamura, S.
Subjects: Physics - Instrumentation and Detectors, Astrophysics - Cosmology and Nongalactic Astrophysics, High Energy Physics - Experiment
Abstract: XMASS-I is a single-phase liquid xenon detector whose purpose is direct detection of dark matter. To achieve the low background requirements necessary in the detector, a new model of photomultiplier tubes (PMTs), R10789, with a hexagonal window was developed based on the R8778 PMT used in the XMASS prototype detector. We screened the numerous component materials for their radioactivity. During development, the largest contributions to the reduction of radioactivity came from the stem and the dynode support. The glass stem was exchanged to the Kovar alloy one and the ceramic support were changed to the quartz one. R10789 is the first model of Hamamatsu Photonics K. K. that adopted these materials for low background purposes and provided a groundbreaking step for further reductions of radioactivity in PMTs. Measurements with germanium detectors showed 1.2$\pm$0.3 mBq/PMT of $^{226}$Ra, less than 0.78 mBq/PMT of $^{228}$Ra, 9.1$\pm$2.2 mBq/PMT of $^{40}$K, and 2.8$\pm$0.2 mBq/PMT of $^{60}$Co. In this paper, the radioactive details of the developed R10789 are described together with our screening methods and the components of the PMT., Comment: 7 pages, 3 figures
Published: 2018
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39. Search for dark matter in the form of hidden photons and axion-like particles in the XMASS detector

Author: XMASS Collaboration, Abe, K., Hiraide, K., Ichimura, K., Kishimoto, Y., Kobayashi, K., Kobayashi, M., Moriyama, S., Nakahata, M., Ogawa, H., Sato, K., Sekiya, H., Suzuki, T., Takachio, O., Takeda, A., Tasaka, S., Yamashita, M., Yang, B. S., Kim, N. Y., Kim, Y. D., Itow, Y., Kanzawa, K., Masuda, K., Martens, K., Suzuki, Y., Xu, B. D., Miuchi, K., Oka, N., Takeuchi, Y., Kim, Y. H., Lee, K. B., Lee, M. K., Fukuda, Y., Miyasaka, M., Nishijima, K., Fushimi, K., Kanzaki, G., and Nakamura, S.
Subjects: Astrophysics - Cosmology and Nongalactic Astrophysics, High Energy Physics - Experiment, Physics - Instrumentation and Detectors
Abstract: Hidden photons and axion-like particles are candidates for cold dark matter if they were produced non-thermally in the early universe. We conducted a search for both of these bosons using 800 live-days of data from the XMASS detector with 327 kg of liquid xenon in the fiducial volume. No significant signal was observed, and thus we set constraints on the $\alpha' / \alpha$ parameter related to kinetic mixing of hidden photons and the coupling constant $g_{Ae}$ of axion-like particles in the mass range from 40 to 120 keV/$c^2$, resulting in $\alpha' / \alpha < 6 \times 10^{-26}$ and $g_{Ae} < 4 \times 10^{-13}$. These limits are the most stringent derived from both direct and indirect searches to date., Comment: 18 pages, 5 figures
Published: 2018
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40. A direct dark matter search in XMASS-I

Author: XMASS Collaboration, Abe, K., Hiraide, K., Ichimura, K., Kishimoto, Y., Kobayashi, K., Kobayashi, M., Moriyama, S., Nakahata, M., Norita, T., Ogawa, H., Sato, K., Sekiya, H., Takachio, O., Takeda, A., Tasaka, S., Yamashita, M., Yang, B. S., Kim, N. Y., Kim, Y. D., Itow, Y., Kanzawa, K., Kegasa, R., Masuda, K., Takiya, H., Fushimi, K., Kanzaki, G., Martens, K., Suzuki, Y., Xu, B. D., Fujita, R., Hosokawa, K., Miuchi, K., Oka, N., Takeuchi, Y., Kim, Y. H., Lee, K. B., Lee, M. K., Fukuda, Y., Miyasaka, M., Nishijima, K., and Nakamura, S.
Subjects: Astrophysics - Cosmology and Nongalactic Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, Physics - Instrumentation and Detectors
Abstract: A search for dark matter using an underground single-phase liquid xenon detector was conducted at the Kamioka Observatory in Japan, particularly for Weakly Interacting Massive Particles (WIMPs). We have used 705.9 live days of data in a fiducial volume containing 97 kg of liquid xenon at the center of the detector. The event rate in the fiducial volume after the data reduction was ${\rm (4.2 \pm 0.2) \times 10^{-3} \, day^{-1}kg^{-1} keV_{ee}^{-1}}$ at ${\rm 5 \, keV_{ee}}$, with a signal efficiency of ${\rm 20\%}$. All the remaining events are consistent with our background evaluation, mostly of the "mis-reconstructed events" originated from $^{210}$Pb in the copper plates lining the detector's inner surface. The obtained upper limit on a spin-independent WIMP-nucleon cross section was ${\rm 2.2 \times 10^{-44} \, cm^{2}}$ for a WIMP mass of ${\rm 60 \, GeV/c^{2}}$ at the $90\%$ confidence level, which was the most stringent limit among results from single-phase liquid xenon detectors., Comment: 16 pages, 8 figures
Published: 2018
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41. Direct dark matter search by annual modulation with 2.7 years of XMASS-I data

Author: XMASS Collaboration, Abe, K., Hiraide, K., Ichimura, K., Kishimoto, Y., Kobayashi, K., Kobayashi, M., Moriyama, S., Nakahata, M., Norita, T., Ogawa, H., Sato, K., Sekiya, H., Takachio, O., Takeda, A., Tasaka, S., Yamashita, M., Yang, B. S., Kim, N. Y., Kim, Y. D., Itow, Y., Kanzawa, K., Kegasa, R., Masuda, K., Takiya, H., Fushimi, K., Kanzaki, G., Martens, K., Suzuki, Y., Xu, B. D., Fujita, R., Hosokawa, K., Miuchi, K., Oka, N., Takeuchi, Y., Kim, Y. H., Lee, K. B., Lee, M. K., Fukuda, Y., Miyasaka, M., Nishijima, K., and Nakamura, S.
Subjects: Astrophysics - Cosmology and Nongalactic Astrophysics, High Energy Physics - Experiment, Nuclear Experiment
Abstract: An annual modulation signal due to the Earth orbiting around the Sun would be one of the strongest indications of the direct detection of dark matter. In 2016, we reported a search for dark matter by looking for this annual modulation with our single-phase liquid xenon XMASS-I detector. That analysis resulted in a slightly negative modulation amplitude at low energy. In this work, we included more than one year of additional data, which more than doubles the exposure to 800 live days with the same 832 kg target mass. When we assume weakly interacting massive particle (WIMP) dark matter elastically scattering on the xenon target, the exclusion upper limit for the WIMP-nucleon cross section was improved by a factor of 2 to 1.9$\times$10$^{-41}$cm$^2$ at 8 GeV/c$^2$ at 90\% confidence level with our newly implemented data selection through a likelihood method. For the model-independent case, without assuming any specific dark matter model, we obtained more consistency with the null hypothesis than before with a $p$-value of 0.11 in the 1$-$20 keV energy region. This search probed this region with an exposure that was larger than that of DAMA/LIBRA. We also did not find any significant amplitude in the data for periodicity with periods between 50 and 600 days in the energy region between 1 to 6 keV., Comment: 10 pages, 11 figures
Published: 2018
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42. Improved search for two-neutrino double electron capture on $^{124}$Xe and $^{126}$Xe using particle identification in XMASS-I

Author: XMASS Collaboration, Abe, K., Hiraide, K., Ichimura, K., Kishimoto, Y., Kobayashi, K., Kobayashi, M., Moriyama, S., Nakahata, M., Norita, T., Ogawa, H., Sato, K., Sekiya, H., Takachio, O., Takeda, A., Tasaka, S., Yamashita, M., Yang, B. S., Kim, N. Y., Kim, Y. D., Itow, Y., Kanzawa, K., Kegasa, R., Masuda, K., Takiya, H., Fushimi, K., Kanzaki, G., Martens, K., Suzuki, Y., Xu, B. D., Fujita, R., Hosokawa, K., Miuchi, K., Oka, N., Takeuchi, Y., Kim, Y. H., Lee, K. B., Lee, M. K., Fukuda, Y., Miyasaka, M., Nishijima, K., and Nakamura, S.
Subjects: Nuclear Experiment, High Energy Physics - Experiment, Physics - Instrumentation and Detectors
Abstract: We conducted an improved search for the simultaneous capture of two $K$-shell electrons on the $^{124}$Xe and $^{126}$Xe nuclei with emission of two neutrinos using 800.0 days of data from the XMASS-I detector. A novel method to discriminate $\gamma$-ray/$X$-ray or double electron capture signals from $\beta$-ray background using scintillation time profiles was developed for this search. No significant signal was found when fitting the observed energy spectra with the expected signal and background. Therefore, we set the most stringent lower limits on the half-lives at $2.1 \times 10^{22}$ and $1.9 \times 10^{22}$ years for $^{124}$Xe and $^{126}$Xe, respectively, with 90% confidence level. These limits improve upon previously reported values by a factor of 4.5., Comment: 17 pages, 9 figures, accepted for publication in PTEP
Published: 2018
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43. Identification of $^{210}$Pb and $^{210}$Po in the bulk of copper samples with a low-background alpha particle counter

Author: XMASS collaboration, Abe, K., Hiraide, K., Ichimura, K., Kishimoto, Y., Kobayashi, K., Kobayashi, M., Moriyama, S., Nakahata, M., Norita, T., Ogawa, H., Sato, K., Sekiya, H., Takachio, O., Takeda, A., Tasaka, S., Yamashita, M., Yang, B. S., Kim, N. Y., Kim, Y. D., Itow, Y., Kanzawa, K., Kegasa, R., Masuda, K., Takiya, H., Fushimi, K., Kanzaki, G., Martens, K., Suzuki, Y., Xu, B. D., Fujita, R., Hosokawa, K., Miuchi, K., Oka, N., Takeuchi, Y., Kim, Y. H., Lee, K. B., Lee, M. K., Fukuda, Y., Miyasaka, M., Nishijima, K., and Nakamura, S.
Subjects: Physics - Instrumentation and Detectors
Abstract: We established a method to assay $^{210}$Pb and $^{210}$Po contaminations in the bulk of copper samples using a low-background alpha particle counter. The achieved sensitivity for the $^{210}$Pb and $^{210}$Po contaminations reaches a few mBq/kg. Due to this high sensitivity, the $^{210}$Pb and $^{210}$Po contaminations in oxygen free copper bulk were identified and measured for the first time. The $^{210}$Pb contaminations of our oxygen free copper samples were 17-40 mBq/kg. Based on our investigation of copper samples in each production step, the $^{210}$Pb in oxygen free copper was understood to be a small residual of an electrolysis process. This method to measure bulk contaminations of $^{210}$Pb and $^{210}$Po could be applied to other materials., Comment: 6 pages, 8 figures
Published: 2017
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44. Search for solar Kaluza-Klein axion by annual modulation with the XMASS-I detector

Author: XMASS Collaboration, Oka, N., Abe, K., Hiraide, K., Ichimura, K., Kishimoto, Y., Kobayashi, K., Kobayashi, M., Moriyama, S., Nakahata, M., Norita, T., Ogawa, H., Sato, K., Sekiya, H., Takachio, O., Takeda, A., Tasaka, S., Yamashita, M., Yang, B. S., Kim, N. Y., Kim, Y. D., Itow, Y., Kanzawa, K., Kegasa, R., Masuda, K., Takiya, H., Fushimi, K., Kanzaki, G., Martens, K., Suzuki, Y., Xu, B. D., Fujita, R., Hosokawa, K., Miuchi, K., Takeuchi, Y., Kim, Y. H., Lee, K. B., Lee, M. K., Fukuda, Y., Miyasaka, M., Nishijima, K., and Nakamura, S.
Subjects: High Energy Physics - Experiment, Astrophysics - Cosmology and Nongalactic Astrophysics, High Energy Physics - Phenomenology, Nuclear Experiment, Physics - Instrumentation and Detectors
Abstract: In theories with the large extra dimensions beyond the standard 4-dimensional spacetime, axions could propagate in such extra dimensions, and acquire Kaluza-Klein (KK) excitations. These KK axions are produced in the Sun and could solve unexplained heating of the solar corona. While most of the solar KK axions escape from the solar system, a small fraction is gravitationally trapped in orbits around the Sun. They would decay into two photons inside a terrestrial detector. The event rate is expected to modulate annually depending on the distance from the Sun. We have searched for the annual modulation signature using $832\times 359$ kg$\cdot$days of XMASS-I data. No significant event rate modulation is found, and hence we set the first experimental constraint on the KK axion-photon coupling of $4.8 \times 10^{-12}\, \mathrm{GeV}^{-1}$ at 90% confidence level for a KK axion number density of $\bar{n}_\mathrm{a} = 4.07 \times 10^{13}\, \mathrm{m}^{-3}$, the total number of extra dimensions $n = 2$, and the number of extra dimensions $\delta = 2$ that axions can propagate in., Comment: 11 pages, 6 figures, published in PTEP
Published: 2017
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45. Direct dark matter search by annual modulation in XMASS-I

Author: XMASS Collaboration, Abe, K., Hiraide, K., Ichimura, K., Kishimoto, Y., Kobayashi, K., Kobayashi, M., Moriyama, S., Nakahata, M., Norita, T., Ogawa, H., Sekiya, H., Takachio, O., Takeda, A., Yamashita, M., Yang, B. S., Kim, N. Y., Kim, Y. D., Tasaka, S., Fushimi, K., Liu, J., Martens, K., Suzuki, Y., Xu, B. D., Fujita, R., Hosokawa, K., Miuchi, K., Onishi, Y., Oka, N., Takeuchi, Y., Kim, Y. H., Lee, J. S., Lee, K. B., Lee, M. K., Fukuda, Y., Itow, Y., Kegasa, R., Masada, K., Takiya, H., Nishijima, K., and Nakamura, S.
Subjects: Astrophysics - Cosmology and Nongalactic Astrophysics, High Energy Physics - Experiment, Nuclear Experiment, Physics - Instrumentation and Detectors
Abstract: A search for dark matter was conducted by looking for an annual modulation signal due to the Earth's rotation around the Sun using XMASS, a single phase liquid xenon detector. The data used for this analysis was 359.2 live days times 832 kg of exposure accumulated between November 2013 and March 2015. When we assume Weakly Interacting Massive Particle (WIMP) dark matter elastically scattering on the target nuclei, the exclusion upper limit of the WIMP-nucleon cross section 4.3$\times$10$^{-41}$cm$^2$ at 8 GeV/c$^2$ was obtained and we exclude almost all the DAMA/LIBRA allowed region in the 6 to 16 GeV/c$^2$ range at $\sim$10$^{-40}$cm$^2$. The result of a simple modulation analysis, without assuming any specific dark matter model but including electron/$\gamma$ events, showed a slight negative amplitude. The $p$-values obtained with two independent analyses are 0.014 and 0.068 for null hypothesis, respectively. we obtained 90\% C.L. upper bounds that can be used to test various models. This is the first extensive annual modulation search probing this region with an exposure comparable to DAMA/LIBRA., Comment: 5 pages, 4 figures
Published: 2015

46. Search for double-beta decay of 136Xe to excited states of 136Ba with the KamLAND-Zen experiment

Author: Collaboration, KamLAND-Zen, Asakura, K., Gando, A., Gando, Y., Hachiya, T., Hayashida, S., Ikeda, H., Inoue, K., Ishidoshiro, K., Ishikawa, T., Ishio, S., Koga, M., Matsuda, S., Mitsui, T., Motoki, D., Nakamura, K., Obara, S., Otani, M., Oura, T., Shimizu, I., Shirahata, Y., Shirai, J., Suzuki, A., Tachibana, H., Tamae, K., Ueshima, K., Watanabe, H., Xu, B. D., Yoshida, H., Kozlov, A., Takemoto, Y., Yoshida, S., Fushimi, K., Banks, T. I., Berger, B. E., Fujikawa, B. K., O'Donnell, T., Winslow, L. A., Efremenko, Y., Karwowski, H. J., Markoff, D. M., Tornow, W., Detwiler, J. A., Enomoto, S., and Decowski, M. P.
Subjects: High Energy Physics - Experiment, Physics - Instrumentation and Detectors
Abstract: A search for double-beta decays of 136Xe to excited states of 136Ba has been performed with the first phase data set of the KamLAND-Zen experiment. The 0+1, 2+1 and 2+2 transitions of 0{\nu}\{beta}\{beta} decay were evaluated in an exposure of 89.5kg-yr of 136Xe, while the same transitions of 2{\nu}\{beta}\{beta} decay were evaluated in an exposure of 61.8kg-yr. No excess over background was found for all decay modes. The lower half-life limits of the 2+1 state transitions of 0{\nu}\{beta}\{beta} and 2{\nu}\{beta}\{beta} decay were improved to T(0{\nu}, 0+ \rightarrow 2+) > 2.6\times10^25 yr and T(2{\nu}, 0+ \rightarrow 2+) > 4.6\times10^23 yr (90% C.L.), respectively. We report on the first experimental lower half-life limits for the transitions to the 0+1 state of 136Xe for 0{\nu}\{beta}\{beta} and 2{\nu}\{beta}\{beta} decay. They are T (0{\nu}, 0+ \rightarrow 0+) > 2.4\times10^25 yr and T(2{\nu}, 0+ \rightarrow 0+) > 8.3\times10^23 yr (90% C.L.). The transitions to the 2+2 states are also evaluated for the first time to be T(0{\nu}, 0+ \rightarrow 2+) > 2.6\times10^25 yr and T(2{\nu}, 0+ \rightarrow 2+) > 9.0\times10^23 yr (90% C.L.). These results are compared to recent theoretical predictions., Comment: 16 pages, 4 figures. Published in Nuclear Physics A
Published: 2015
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47. KamLAND Sensitivity to Neutrinos from Pre-Supernova Stars

Author: Asakura, K., Gando, A., Gando, Y., Hachiya, T., Hayashida, S., Ikeda, H., Inoue, K., Ishidoshiro, K., Ishikawa, T., Ishio, S., Koga, M., Matsuda, S., Mitsui, T., Motoki, D., Nakamura, K., Obara, S., Oura, T., Shimizu, I., Shirahata, Y., Shirai, J., Suzuki, A., Tachibana, H., Tamae, K., Ueshima, K., Watanabe, H., Xu, B. D., Kozlov, A., Takemoto, Y., Yoshida, S., Fushimi, K., Piepke, A., Banks, T. I., Berger, B. E., Fujikawa, B. K., O'Donnell, T., Learned, J. G., Maricic, J., Matsuno, S., Sakai, M., Winslow, L. A., Efremenko, Y., Karwowski, H. J., Markoff, D. M., Tornow, W., Detwiler, J. A., Enomoto, S., and Decowski, M. P.
Subjects: Astrophysics - High Energy Astrophysical Phenomena, High Energy Physics - Experiment, Physics - Instrumentation and Detectors
Abstract: In the late stages of nuclear burning for massive stars ($M>8~M_{\sun}$), the production of neutrino-antineutrino pairs through various processes becomes the dominant stellar cooling mechanism. As the star evolves, the energy of these neutrinos increases and in the days preceding the supernova a significant fraction of emitted electron anti-neutrinos exceeds the energy threshold for inverse beta decay on free hydrogen. This is the golden channel for liquid scintillator detectors because the coincidence signature allows for significant reductions in background signals. We find that the kiloton-scale liquid scintillator detector KamLAND can detect these pre-supernova neutrinos from a star with a mass of $25~M_{\sun}$ at a distance less than 690~pc with 3$\sigma$ significance before the supernova. This limit is dependent on the neutrino mass ordering and background levels. KamLAND takes data continuously and can provide a supernova alert to the community., Comment: 19 pages, 6 figures, 1 table
Published: 2015
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48. Study of electron anti-neutrinos associated with gamma-ray bursts using KamLAND

Author: Asakura, K., Gando, A., Gando, Y., Hachiya, T., Hayashida, S., Ikeda, H., Inoue, K., Ishidoshiro, K., Ishikawa, T., Ishio, S., Koga, M., Matsuda, S., Mitsui, T., Motoki, D., Nakamura, K., Obara, S., Oki, Y., Oura, T., Shimizu, I., Shirahata, Y., Shirai, J., Suzuki, A., Tachibana, H., Tamae, K., Ueshima, K., Watanabe, H., Xu, B. D., Yoshida, H., Kozlov, A., Takemoto, Y., Yoshida, S., Fushimi, K., Piepke, A., Banks, T. I., Berger, B. E., O'Donnell, T., Fujikawa, B. K., Maricic, J., Learned, J. G., Sakai, M., Winslow, L. A., Efremenko, Y., Karwowski, H. J., Markoff, D. M., Tornow, W., Detwiler, J. A., Enomoto, S., and Decowski, M. P.
Subjects: Astrophysics - High Energy Astrophysical Phenomena, High Energy Physics - Experiment
Abstract: We search for electron anti-neutrinos ($\overline{\nu}_e$) from long and short-duration gamma-ray bursts~(GRBs) using data taken by the KamLAND detector from August 2002 to June 2013. No statistically significant excess over the background level is found. We place the tightest upper limits on $\overline{\nu}_e$ fluence from GRBs below 7 MeV and place first constraints on the relation between $\overline{\nu}_e$ luminosity and effective temperature., Comment: 16 pages and 5 figures
Published: 2015
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49. A compact ultra-clean system for deploying radioactive sources inside the KamLAND detector

Author: Banks, T. I., Freedman, S. J., Wallig, J., Ybarrolaza, N., Gando, A., Gando, Y., Ikeda, H., Inoue, K., Kishimoto, Y., Koga, M., Mitsui, T., Nakamura, K., Shimizu, I., Shirai, J., Suzuki, A., Takemoto, Y., Tamae, K., Ueshima, K., Watanabe, H., Xu, B. D., Yoshida, H., Yoshida, S., Kozlov, A., Grant, C., Keefer, G., Piepke, A., Bloxham, T., Fujikawa, B. K., Han, K., Ichimura, K., Murayama, H., O'Donnell, T., Steiner, H. M., Winslow, L. A., Dwyer, D. A., McKeown, R. D., Zhang, C., Berger, B. E., Lane, C. E., Maricic, J., Miletic, T., Batygov, M., Learned, J. G., Matsuno, S., Sakai, M., Horton-Smith, G. A., Downum, K. E., Gratta, G., Efremenko, Y., Perevozchikov, O., Karwowski, H. J., Markoff, D. M., Tornow, W., Heeger, K. M., Detwiler, J. A., Enomoto, S., and Decowski, M. P.
Subjects: Physics - Instrumentation and Detectors, High Energy Physics - Experiment, Nuclear Experiment
Abstract: We describe a compact, ultra-clean device used to deploy radioactive sources along the vertical axis of the KamLAND liquid-scintillator neutrino detector for purposes of calibration. The device worked by paying out and reeling in precise lengths of a hanging, small-gauge wire rope (cable); an assortment of interchangeable radioactive sources could be attached to a weight at the end of the cable. All components exposed to the radiopure liquid scintillator were made of chemically compatible UHV-cleaned materials, primarily stainless steel, in order to avoid contaminating or degrading the scintillator. To prevent radon intrusion, the apparatus was enclosed in a hermetically sealed housing inside a glove box, and both volumes were regularly flushed with purified nitrogen gas. An infrared camera attached to the side of the housing permitted real-time visual monitoring of the cable's motion, and the system was controlled via a graphical user interface., Comment: Revised author affiliations, corrected typos, made minor improvements to text, and revised references
Published: 2014
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50. 7Be Solar Neutrino Measurement with KamLAND

Author: Gando, A., Gando, Y., Hanakago, H., Ikeda, H., Inoue, K., Ishidoshiro, K., Ishikawa, H., Kishimoto, Y., Koga, M., Matsuda, R., Matsuda, S., Mitsui, T., Motoki, D., Nakajima, K., Nakamura, K., Obata, A., Oki, A., Oki, Y., Otani, M., Shimizu, I., Shirai, J., Suzuki, A., Tamae, K., Ueshima, K., Watanabe, H., Xu, B. D., Yamada, S., Yamauchi, Y., Yoshida, H., Kozlov, A., Takemoto, Y., Yoshida, S., Grant, C., Keefer, G., McKee, D. W., Piepke, A., Banks, T. I., Bloxham, T., Freedman, S. J., Fujikawa, B. K., Han, K., Hsu, L., Ichimura, K., Murayama, H., O'Donnell, T., Steiner, H. M., Winslow, L. A., Dwyer, D., Mauger, C., McKeown, R. D., Zhang, C., Berger, B. E., Lane, C. E., Maricic, J., Miletic, T., Learned, J. G., Sakai, M., Horton-Smith, G. A., Tang, A., Downum, K. E., Tolich, K., Efremenko, Y., Kamyshkov, Y., Perevozchikov, O., Karwowski, H. J., Markoff, D. M., Tornow, W., Detwiler, J. A., Enomoto, S., Heeger, K., and Decowski, M. P.
Subjects: High Energy Physics - Experiment, Astrophysics - Solar and Stellar Astrophysics, Nuclear Experiment
Abstract: We report a measurement of the neutrino-electron elastic scattering rate of 862 keV 7Be solar neutrinos based on a 165.4 kton-day exposure of KamLAND. The observed rate is 582 +/- 90 (kton-day)^-1, which corresponds to a 862 keV 7Be solar neutrino flux of (3.26 +/- 0.50) x 10^9 cm^-2s^-1, assuming a pure electron flavor flux. Comparing this flux with the standard solar model prediction and further assuming three flavor mixing, a nu_e survival probability of 0.66 +/- 0.14 is determined from the KamLAND data. Utilizing a global three flavor oscillation analysis, we obtain a total 7Be solar neutrino flux of (5.82 +/- 0.98) x 10^9 cm^-2s^-1, which is consistent with the standard solar model predictions., Comment: 8 pages, 6 figures, submitted to Phys. Rev. C
Published: 2014
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