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.

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., Nagao, Y., Nakahata, M., Nakajima, Y., Nakayama, S., Okada, T., Okamoto, K., Orii, A., Pronost, G., Sekiya, H., Shiozawa, M., et al.. - In: ASTROPARTICLE PHYSICS. - ISSN 0927-6505. - 139:(2022), p. 102702. [10.1016/j.astropartphys.2022.102702]

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

Calabria N. F.;De Rosa Gianfranca;
2022

Abstract

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.
2022
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., Nagao, Y., Nakahata, M., Nakajima, Y., Nakayama, S., Okada, T., Okamoto, K., Orii, A., Pronost, G., Sekiya, H., Shiozawa, M., et al.. - In: ASTROPARTICLE PHYSICS. - ISSN 0927-6505. - 139:(2022), p. 102702. [10.1016/j.astropartphys.2022.102702]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11588/880306
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