New results from RENO and prospects with RENO-50

Abstract

RENO (Reactor Experiment for Neutrino Oscillation) has made a definitive measurement of the smallest mixing angle theta13 in 2012, based on the disappearance of electron antineutrinos. More precise measurements have been obtained and presented on the mixing angle and the reactor neutrino spectrum, using ~800 days of data. We have observed an excess of IBD prompt spectrum near 5 MeV with respect to the most commonly used models. The excess is found to be consistent with coming from reactors. We have also successfully measured the reactor neutrino flux with a delayed signal of neutron capture on hydrogen. A future reactor neutrino experiment of RENO-50 is proposed to determine the neutrino mass hierarchy and to make highly precise measurements of theta12, delta(m_21)^2, and delta(m_31)^2. Physics goals and sensitivities of RENO-50 are presented with a strategy of obtaining an extremely good energy resolution toward the neutrino mass hierarchy.