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

Abe, K, Bronner, C, Hayato, Y, Ikeda, M, Imaizumi, S, Ito, H, Kameda, J, Kataoka, Y, Miura, M, Moriyama, S
et al (show 188 more authors) (2022) Search for solar electron anti-neutrinos due to spin-flavor precession in the Sun with Super-Kamiokande-IV. ASTROPARTICLE PHYSICS, 139. p. 102702.

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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.

Item Type: Article
Uncontrolled Keywords: Neutron tagging, Water Cherenkov detector, Electron antineutrinos, Neutrino-antineutrino oscillation, Solar neutrino
Depositing User: Symplectic Admin
Date Deposited: 21 Oct 2022 08:37
Last Modified: 18 Jan 2023 19:49
DOI: 10.1016/j.astropartphys.2022.102702
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