Transcript ppt - Physics - Oklahoma State University

Neutrino Masses
and Lepton Flavor Physics
K.S. Babu
Department of Physics, Oklahoma State University
PHENO 03
Madison, Wisconsin, May 5, 2003
Outline
Neutrino Oscillation Results
Interpreting Data
– Patterns of Neutrino Mass Spectrum
– Neutrinoless Double Beta Decay (bb)0n Tests
Theoretical Modeling
– Large Neutrino Mixing
– Unified Quark-Lepton Description
Lepton Flavor Violation
– Rare Decays t→mg, m→eg
– Lepton Dipole Moments
Conclusions
Solar Neutrino Oscillations
Gonzalez-Garcia et al. (2003)
Atmosphere Neutrino Oscillations
Maltoni, et al. hep-ph/0207227
LSND
Aguilar, et. al hep-exp/0104049
Patterns of Neutrino Mass Spectrum
Neutrino Mixing versus Quark Mixing
Leptons
Quarks
Disparity a challenge for Quark-Lepton unified theories.
(bb)0n and Pattern of Neutrino Masses
(meV)
Pascoli, Petcov, Rodejohann, hep-ph/0212113
Neutrino Masses and the Scale of New Physics
Very Close to the GUT scale.
Gauge Coupling Unification in MSSM
Structure of Matter Multiplets
Large Neutrino Mixing with Lopsided Mass Matrices
Quark and Lepton Mass hierarchy:
This motivates:
KSB and S. Barr, 1995
Example of Lopsided Mass Matrices
Gogoladze, Wang, KSB, 2003
Discrete ZN Gauge Symmetry
Lopsided Mass Matrix Model in SO(10)
S.Barr and KSB,2002
10 Parameters vs. 20 Observables
PREDICTIONS
FIT
Buras, et al
Georgi-Jarlskog
Neutrino Mass Textures
Fukugita, Tanimoto,
Yanagida, 2003
A4 Symmetry and Quasi-degenerate Neutrino
E. Ma, 2002
E. Ma, J. Valle, KSB, 2002
With Arbitrary Soft A4 Breaking
With Complex parameters, arg(Ue3) = p/2
Electric Dipole Moments
Violates CP
Electron:
Neutron:
Phases in SUSY breaking sector contribute to EDM.
SUSY Contributions:
A, B are complex in MSSM
Effective SUSY Phase
If parity is realized asymptotically,
EDM will arise only through non-hermiticity induced by RGE.
Subject to experimental tests
Dutta, Mohapatra, KB (2001)
Lepton Flavor Violation and Neutrino Mass
Seesaw mechanism naturally explains small n-mass.
Current neutrino-oscillation data suggests
Flavor change in neutrino-sector
Flavor change in charged leptons
In standard model with Seesaw, leptonic flavor changing is very tiny.
In Supersymmetric Standard model
For
nR active
flavor violation in neutrino sector Transmitted to Sleptons
Borzumati, Masiero (1986)
Hall, Kostelecky, Raby (1986)
Hisano, et al (1995)
SUSY Seesaw Mechanism
If B-L is gauged, MR must arise through Yukawa couplings.
Flavor violation may reside entirely in f or entirely in Yn
If flavor violation occurs only in Dirac Yukawa Yn (with
mSUGRA)
If flavor violation occurs only in f (Majorana LFV)
LFV in the two scenarios are comparable.
More detailed study is needed.
Neutrino Fit
For Majorana LFV scenario, take
Dutta, Mohapatra, KB 2002
For Dirac LFV scenario
Same neutrino oscillation parameters as in Majorona LFV
The two scenarios differ in predictions for
Dirac LFV
F. Deppisch, et al, hep-ph/0206122
Majorana LFV
Dutta, Mohapatra, KB (2002)
Correlation between LFV and B→fKs
Hisano and Shimizu,
hep-ph/0303071
LFV in SUSY SO(10)
Masiero, Vempati and Vives, hep-ph/0209303
Conclusions
• Neutrino Experiments pinning down oscillation
parameters.
• Neutrinoless double beta decay can discriminate
between various mass patterns.
• Large Neutrino Mixing can arise from Unified
theories through lopsided mass matrices.
• Lepton Flavor Violation t→mg, m→eg, and EDMs
within reach of experiments.