Search for radiative decays of cosmic background neutrino using cosmic infrared background energy spectrum

摘要

We propose to search for the neutrino radiative decay by fitting a photon energy spectrum of the cosmic infrared background to a sum of the photon energy spectrum from the neutrino radiative decay and a continuum. By comparing the present cosmic infrared background energy spectrum observed by AKARI and Spitzer to the photon energy spectrum expected from neutrino radiative decay with a maximum likelihood method, we obatined a lifetime lower limit of 3.1 × 10 ~(12) to 3.8 × 10 ~(12) years at 95% confidence level for the third generation neutrino v _3 in the v _3 mass range between 50 and 150 meV/c ~2 under the present constraints by the neutrino oscillation measurements. In the left-right symmetric model, the minimum lifetime of v _3 is predicted to be 1.5 × 10 ~(17) years for m 3 of 50 meV/c 2. We studied the feasibility of the observation of the neutrino radiative decay with a lifetime of 1.5 × 10 ~(17) years, by measuring a continuous energy spectrum of the cosmic infrared background.