Center for Underground Physics at Institute for Basic Science (CUP/IBS) is trying to investigate rare physical processes such as the interactions of neutrinos and dark matters. Pre-stages of a neutrinoless double beta decay experiment (AMoRE) and a Weakly-interacting-Massive-Particle search experiment (COSINE) have been running in the Yangyang Underground Laboratory. And the main stage of AMoRE and other experiments will be conducted in a newly constructed underground laboratory. A coherent elastic neutrino-nucleus scattering experiment using NaI crystals (NEON) has been launched recently. NEOS, as a part of neutrino programs in CUP, is to search for an active-to-sterile neutrino oscillation using a commercial nuclear reactor. The inverse beta decay of the electron antineutrino is measured with a 1000 liters of Gd-loaded liquid scintillator detector, located at 24 meter distance from the Hanbit-5 reactor. We have found no strong evidence of the short baseline neutrino oscillation from the measurement of 180 livedays of reactor-on and 46 livedays of reactor-off in Phase-I. To enhance the sensitivity for the light sterile neutrino search and for a better understanding of the reactor neutrino spectrum, Phase-II measurement has been conducted for a full reactor fuel cycle from 2018 to 2020. Analysis of the Phase-II data and a joint analysis with RENO is on-going.

Contact : tellier@ill.fr