Observations of solar neutrinos and supernova neutrinos in Hyper-Kamiokande (HK) are discussed. The current solar neutrino observation in Super-Kamioande(SK) shows a tension in Delta m^2_{12} between solar and reactor neutrino measurements. It might indicate hint of some new physics. Quite high statistics of solar neutrino events in HK enable us to discussed the difference with high statistical significance in future by comparing HK results with the JUNO reactor measurement. JUNO and SK-Gd (gadolinium-loaded phase of SK) would discover supernova relic neutrinos (SRN). However, they would not have enough statistics to discuss spectrum of SRN. HK should be able to measure shape of energy spectrum down to 10 MeV and it would reveal supernova history in the universe back to red-shift (z) of one. If a galactic supernova occurs, large number of events are expected at HK. We can discuss evolution of explosion with time variation of event rate and neutrino temperature. In addition, HK might be able to detect dozens neutrino events from nearby galaxies upto several mega parsec.

报告人简介：中畑雅行（Masayuki Nakahata）是东京大学数物联合宇宙研究所的主任研究员，自2007年任职至今。他在东京大学宇宙线研究所神冈实验室担任实验室主任，并担任超级神冈实验的发言人一职。中畑教授的研究兴趣包括实验物理（天体粒子物理），暗物质探测，以及中微子物理，曾参与1987A超新星爆发中微子观测、太阳中微子振荡等多项重要实验研究。