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arXiv · 2012.03807

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

Kamiokande Collaboration·K. Abe·C. Bronner·Y. Hayato·M. Ikeda·S. Imaizumi·H. Ito·J. Kameda·Y. Kataoka·M. Miura·S. Moriyama·Y. Nagao·M. Nakahata·Y. Nakajima·S. Nakayama·T. Okada·K. Okamoto·A. Orii·G. Pronost·H. Sekiya·M. Shiozawa·Y. Sonoda·Y. Suzuki·A. Takeda·Y. Takemoto·A. Takenaka·H. Tanaka·T. Yano·R. Akutsu·S. Han·T. Kajita·K. Okumura·T. Tashiro·R. Wang·J. Xia·D. Bravo-Berguño·L. Labarga·Ll. Marti·B. Zaldivar·F. d. M. Blaszczyk·E. Kearns·J. L. Raaf·J. L. Stone·L. Wan·T. Wester·B. W. Pointin·J. Bian·N. J. Griskevich·W. R. Kropp·S. Locke·S. Mine·M. B. Smy·H. W. Sobel·V. Takhistov·P. Weatherly·J. Hill·J. Y. Kim·I. T. Lim·R. G. Park·B. Bodur·K. Scholberg·C. W. Walter·L. Bernard·A. Coffani·O. Drapier·S. El Hedri·A. Giampaolo·M. Gonin·Th. A. Mueller·P. Paganini·B. Quilain·T. Ishizuka·T. Nakamura·J. S. Jang·J. G. Learned·L. H. V. Anthony·A. A. Sztuc·Y. Uchida·V. Berardi·M. G. Catanesi·E. Radicioni·N. F. Calabria·L. N. Machado·G. De Rosa·G. Collazuol·F. Iacob·M. Lamoureux·N. Ospina·L. Ludovici·Y. Nishimura·S. Cao·M. Friend·T. Hasegawa·T. Ishida·M. Jakkapu·T. Kobayashi·T. Matsubara·T. Nakadaira·K. Nakamura·Y. Oyama
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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.

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Kamiokande Collaboration, K. Abe, C. Bronner, Y. Hayato, M. Ikeda, S. Imaizumi, H. Ito, J. Kameda, Y. Kataoka, M. Miura, S. Moriyama, Y. Nagao, M. Nakahata, Y. Nakajima, S. Nakayama, T. Okada, K. Okamoto, A. Orii, G. Pronost, H. Sekiya, M. Shiozawa, Y. Sonoda, Y. Suzuki, A. Takeda, Y. Takemoto, A. Takenaka, H. Tanaka, T. Yano, R. Akutsu, S. Han, T. Kajita, K. Okumura, T. Tashiro, R. Wang, J. Xia, D. Bravo-Berguño, L. Labarga, Ll. Marti, B. Zaldivar, F. d. M. Blaszczyk, E. Kearns, J. L. Raaf, J. L. Stone, L. Wan, T. Wester, B. W. Pointin, J. Bian, N. J. Griskevich, W. R. Kropp, S. Locke, S. Mine, M. B. Smy, H. W. Sobel, V. Takhistov, P. Weatherly, J. Hill, J. Y. Kim, I. T. Lim, R. G. Park, B. Bodur, K. Scholberg, C. W. Walter, L. Bernard, A. Coffani, O. Drapier, S. El Hedri, A. Giampaolo, M. Gonin, Th. A. Mueller, P. Paganini, B. Quilain, T. Ishizuka, T. Nakamura, J. S. Jang, J. G. Learned, L. H. V. Anthony, A. A. Sztuc, Y. Uchida, V. Berardi, M. G. Catanesi, E. Radicioni, N. F. Calabria, L. N. Machado, G. De Rosa, G. Collazuol, F. Iacob, M. Lamoureux, N. Ospina, L. Ludovici, Y. Nishimura, S. Cao, M. Friend, T. Hasegawa, T. Ishida, M. Jakkapu, T. Kobayashi, T. Matsubara, T. Nakadaira, K. Nakamura, Y. Oyama. 2020-12-07. Search for solar electron anti-neutrinos due to spin-flavor precession in the Sun with Super-Kamiokande-IV. https://doi.org/10.1016/j.astropartphys.2022.102702

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