Probing Sterile Neutrino Via Lepton Flavor Violating Decays Of Mesons

A sterile neutrino of(GeV)mass,if it exists,will not participate in the neutrino oscillation process and breaks the unitarity of PMNS matrix.Distinct from tiny mass neutrino,the heav-ier sterile neutrino will also affect flavor changing process which should be rare in SM.In this work,we calculated a box diagram contribution in these processes and investigate the leptonic and semileptonic B decays,Kaon decays and D decays with different flavor of final leptons.The ster-ile neutrino can be produced on-shell in semileptonic.Combining two kinds of decay and current experimental data,a limit of certain PMNS matrix element relevant to sterile neutrino is given.Ac-cording to the different mass region,we classify the mass range of four different scenarios.If mass region of sterile neutrino between located in pion and kaon mass,K+→π+μ±e(?)provides the most stringnt constraint.When MK<mN<MB,the semileptonic dAcay B+→π+μ±e(?)gives the most stringent constraint.Tf mN>MB,the leptonic decay B(s)0→μ±e(?)provides the dominated constraint.