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

9

9

9

1

ep

S

5

1

1

v

09

3

9

9

9

/

h

p

-

p

e

:hv

i

X

r

aWIS-99/31/Sept-DPPSLAC-PUB-8244hep-ph/9909390September1999Canlepton avorviolatinginteractionsexplaintheatmosphericneutrinoproblem?SvenBergmann,aYuvalGrossmanbandDamienM.PiercecaDepartmentofParticlePhysicsWeizmannInstituteofScience,Rehovot76100,IsraelbStanfordLinearAcceleratorCenterStanfordUniversity,Stanford,CA94309cBrookhavenNationalLaboratoryUpton,NY11973AbstractWeinvestigatewhether avorchangingneutrinointeractions(FCNIs)canbesu cientlylargetoprovideaviablesolutiontotheatmosphericneutrinoproblem.E ectiveoperatorsinducedbyheavybosonexchangethatallowfor avorchangingneutrinoscatteringo quarksorelectronsarerelatedbyanSU(2)Lrotationtooperatorsthatinduceanomaloustaudecays.Since

SU(2)LviolationissmallforNewPhysicsatorabovetheweakscale,one

canusetheupperboundsonlepton avorviolatingtaudecaysoronlepton

universalityviolationtoputsevere,model-independentboundsontherelevant

non-standardneutrinointeractions.AlsoZ-induced avorchangingneutral

currents,duetoheavysingletneutrinos,aretoosmalltoberelevantforthe

atmosphericneutrinoanomaly.WeconcludethattheFCNIsolutiontothe

atmosphericneutrinoproblemisruledout.