Description
An appearance of electron antineutrinos in the solar neutrino flux opens a new window for the new physics beyond the standard model due to a very low production rate of electron antineutrinos via nuclear fusion in the Sun. In particular, a spin-flavor precession process is expected to convert an electron neutrino into an electron antineutrino when neutrino has a finite magnetic moment. We have searched for solar electron antineutrinos in the Super-Kamiokande, using neutron tagging to identify their inverse beta decay signature. We identified 78 electron antineutrino candidates for neutrino energies of 9.3 to 17.3 MeV in 183.0 kton·year exposure. The energy spectrum has been consistent with background predictions and we thus derived a 90%CL upper limit of $4.7\times10^{−4}$ on the neutrino-to-antineutrino conversion probability in the Sun. In this presentation, we will report the result and detail, then discuss to evaluate the sensitivity of notably the Super-Kamiokande Gadolinium (SK-Gd).
| Collaboration | The Super-Kamiokande collaboration |
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