Muon capture reaction on ${}^{100}Mo$ to study nuclear responses for double beta decays and astro-neutrinos

The negative-muon capture reaction (MCR) on the enriched ${}^{100}Mo$ isotope was studied for the first time to investigate neutrino nuclear response for neutrino-less double beta decays and supernova neutrino nuclear interactions. MCR on ${}^{100}Mo$ proceeds mainly as ${}^{100}Mo(mu,xn{)}^{100-x}Nb$ with $x$ being the number of neutrons emitted from MCR. The Nb isotope mass distribution was obtained by measuring delayed gamma-rays from radioactive ${}^{100-x}Nb$. By using the neutron emission model after MCR, the neutrino response (the strength distribution) for MCR was derived. Giant resonance (GR)-like distribution at the peak energy around 11-14 MeV, suggests concentration of the MCR strength at the muon capture GR region.