Search for Neutron EDM by Using Crystal Diffraction Method

Abstract

The existence of permanent neutron electric dipole moment(nEDM) violates the time reversal symmetry, therefore this is good probe for search CP violation from new physics beyond the standard model of particle physics(assuming CPT= 1). The present upper limit was measured by using stored ultra-cold neutrons. Now we consider nEDM measurement by crystal diffraction of thermal neutrons. Candidates of the crystal are α-Quarts, BGO, DKDP. the experimental feasibility is discussed. At J-PARC BL17, about 80 days measurement reaches to the sensitivity of d n = 10 −26 [e • cm] using (046) plane of BGO crystal.