Search for proton decay via $p\to e^+π^0$ and $p\to μ^+π^0$ with an enlarged fiducial volume in Super-Kamiokande I-IV

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Collaboration, Super-Kamiokande, Takenaka, A, Abe, K, Bronner, C, Hayato, Y, Ikeda, M, Imaizumi, S, Ito, H, Kameda, J, Kataoka, Y et al (show 205 more authors) , 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, FDM, Kearns, E, Raaf, JL, Stone, JL, Wan, L, Wester, T, Pointon, BW, Bian, J, Griskevich, NJ, Kropp, WR, Locke, S, Mine, S, Smy, MB, Sobel, HW, Takhistov, V, Weatherly, P, Ganezer, KS, Hill, J, Kim, JY, Lim, IT, Park, RG, Bodur, B, Scholberg, K, Walter, CW, Coffani, A, Drapier, O, Hedri, S El, Giampaolo, A, Gonin, M, Mueller, Th A, Paganini, P, Quilain, B, Ishizuka, T, Nakamura, T, Jang, JS, Learned, JG, Matsuno, S, Anthony, LHV, Litchfield, RP, Sztuc, AA, Uchida, Y, Berardi, V, Catanesi, MG, Radicioni, E, Calabria, NF, Machado, LN, Rosa, G De, 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, AT, Takeuchi, Y, Yamamoto, S, Ali, A, Ashida, Y, Feng, J, Hirota, S, Ichikawa, AK, Jiang, M, Kikawa, T, Mori, M, Nakamura, KE, Nakaya, T, Wendell, RA, Yasutome, K, McCauley, N ORCID: 0000-0002-5982-5125, Mehta, P, Pritchard, A, Tsui, KM, Fukuda, Y, Itow, Y, Menjo, H, Niwa, T, Sato, K, Taani, M, Tsukada, M, Mijakowski, P, Frankiewicz, K, Jung, CK, Santucci, G, Vilela, C, Wilking, MJ, 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, Lodovico, F Di, Sedgwick, S Molina, Zsoldos, S, Yang, JY, Jenkins, SJ ORCID: 0000-0002-0982-8141, McElwee, JM, Thiesse, MD, Thompson, LF, Okazawa, H, Choi, Y, Kim, SB, Yu, I, Nishijima, K, Koshiba, M, Iwamoto, K, Ogawa, N, Yokoyama, M, Goldsack, A, Martens, K, Vagins, MR, Kuze, M, Tanaka, M, Yoshida, T, Inomoto, M, Ishitsuka, M, Matsumoto, R, Ohta, K, Shinoki, M, Martin, JF, Nantais, CM, Tanaka, HA, Towstego, T, Hartz, M, Konaka, A, Perio, P de, Prouse, NW, Chen, S, Xu, BD, Posiadala-Zezula, M, Richards, B, Jamieson, B, Walker, J, Minamino, A, Okamoto, K, Pintaudi, G and Sasaki, R (2020) Search for proton decay via $p\to e^+π^0$ and $p\to μ^+π^0$ with an enlarged fiducial volume in Super-Kamiokande I-IV [Preprint]

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Abstract

We have searched for proton decay via $p\to e^+π^0$ and $p\to μ^+π^0$ 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 $p\to e^+π^0$ and one candidate remains for $p\to μ^+π^0$ 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: $τ/B(p\to e^+π^0) > 2.4 \times 10^{34}$ years and $τ/B(p\to μ^+π^0) > 1.6 \times 10^{34}$ years at 90% confidence level.

Item Type:	Preprint
Additional Information:	16 pages, 10 figures
Uncontrolled Keywords:	hep-ex, hep-ex
Divisions:	Faculty of Science & Engineering Faculty of Science & Engineering > School of Physical Sciences Faculty of Science & Engineering > School of Physical Sciences > Physics
Depositing User:	Symplectic Admin
Date Deposited:	01 Dec 2025 09:17
Last Modified:	22 Apr 2026 04:57
DOI:	10.48550/arxiv.2010.16098
Open Access URL:	https://journals.aps.org/prd/abstract/10.1103/Phys...
Related Websites:	Author Publisher
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3195706
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