We investigate whether flavor changing neutrino interactions (FCNIs) can be sufficiently large to provide a viable solution to the atmospheric neutrino problem. Effective operators induced by heavy boson exchange that allow for flavor changing neutrino sca

atenergieswellbelowthebosonmassMB.Thus,intermsofthetrilinearcouplingλαfthatdescribesthecouplingofsomeheavybosonBtoνα(α=µ,τ)andachargedfermionf=u,d,ethee ectiveparametersin(1.1)aregivenby

fν=λ τfλµf

22MBGFandf ′ν|λτf|2 |λµf|2=.22MBGF(2.2)

Thecrucialpointofouranalysisisthefollowing:SincetheSMneutrinosarecomponents

′fofSU(2)Ldoublets,thesametrilinearcouplingsλαfthatgiverisetonon-zero for ννalso

induceotherfour-fermionoperators.TheseoperatorsinvolvetheSU(2)Lpartnersoftheneutrinos,i.e.thechargedleptons,andcanbeusedtoconstraintherelevantcouplings.

BilinearB

(LL)s

(LL)t

¯)s(LL

¯)t(LLCouplestoBosonBS(1,1,1)S(1,3,1)Example c(SUSYR p)R L(LRSM)5.9(M1/M2)2maxV(1,1,0)V(1,3,0)

¯RLd

(LQ)t

¯)s(LQ

LuR¯,2, 1/6)S(3¯,3,1/3)S(3¯,1, 2/3)V(3¯,2, 1/6)V(3 c(SUSYRQp)5.22.5

¯)t(QQ

Tab.3:Quark-QuarkBilinearsV(1,3,0)