TY - JOUR
T1 - Search for solar electron anti-neutrinos due to spin-flavor precession in the Sun with Super-Kamiokande-IV
AU - Super-Kamiokande Collaboration
AU - Abe, K.
AU - Bronner, C.
AU - Hayato, Y.
AU - Ikeda, M.
AU - Imaizumi, S.
AU - Ito, H.
AU - Kameda, J.
AU - Kataoka, Y.
AU - Miura, M.
AU - Moriyama, S.
AU - Nagao, Y.
AU - Nakahata, M.
AU - Nakajima, Y.
AU - Nakayama, S.
AU - Okada, T.
AU - Okamoto, K.
AU - Orii, A.
AU - Pronost, G.
AU - Sekiya, H.
AU - Shiozawa, M.
AU - Sonoda, Y.
AU - Suzuki, Y.
AU - Takeda, A.
AU - Takemoto, Y.
AU - Takenaka, A.
AU - Tanaka, H.
AU - Yano, T.
AU - Akutsu, R.
AU - Han, S.
AU - Kajita, T.
AU - Okumura, K.
AU - Tashiro, T.
AU - Wang, R.
AU - Xia, J.
AU - Bravo-Berguño, D.
AU - Labarga, L.
AU - Marti, Ll
AU - Zaldivar, B.
AU - Blaszczyk, F. D.M.
AU - Kearns, E.
AU - Raaf, J. L.
AU - Stone, J. L.
AU - Wan, L.
AU - Wester, T.
AU - Pointon, B. W.
AU - Bian, J.
AU - Griskevich, N. J.
AU - Kropp, W. R.
AU - Locke, S.
AU - Nishimura, Y.
N1 - Publisher Copyright:
© 2022 The Authors
PY - 2022/6
Y1 - 2022/6
N2 - Due to a very low production rate of electron anti-neutrinos (ν̄e) via nuclear fusion in the Sun, a flux of solar ν̄e is unexpected. An appearance of ν̄e 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 (νe→ν̄e) when neutrino has a finite magnetic moment. In this work, we have searched for solar ν̄e in the Super-Kamiokande experiment, using neutron tagging to identify their inverse beta decay signature. We identified 78 ν̄e 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⋅year exposure). The energy spectrum has been consistent with background predictions and we thus derived a 90% confidence level upper limit of 4.7×10−4 on the νe→ν̄e conversion probability in the Sun. We used this result to evaluate the sensitivity of future experiments, notably the Super-Kamiokande Gadolinium (SK-Gd) upgrade.
AB - Due to a very low production rate of electron anti-neutrinos (ν̄e) via nuclear fusion in the Sun, a flux of solar ν̄e is unexpected. An appearance of ν̄e 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 (νe→ν̄e) when neutrino has a finite magnetic moment. In this work, we have searched for solar ν̄e in the Super-Kamiokande experiment, using neutron tagging to identify their inverse beta decay signature. We identified 78 ν̄e 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⋅year exposure). The energy spectrum has been consistent with background predictions and we thus derived a 90% confidence level upper limit of 4.7×10−4 on the νe→ν̄e conversion probability in the Sun. We used this result to evaluate the sensitivity of future experiments, notably the Super-Kamiokande Gadolinium (SK-Gd) upgrade.
KW - Electron antineutrinos
KW - Neutrino–antineutrino oscillation
KW - Neutron tagging
KW - Solar neutrino
KW - Water Cherenkov detector
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U2 - 10.1016/j.astropartphys.2022.102702
DO - 10.1016/j.astropartphys.2022.102702
M3 - Article
AN - SCOPUS:85126629624
SN - 0927-6505
VL - 139
JO - Astroparticle Physics
JF - Astroparticle Physics
M1 - 102702
ER -