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

Understand

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.