Leptonflavor violation in SUSY models

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Lepton-flavor violation in SUSY models
and the related topics
Junji Hisano (ICRR, Univ. of Tokyo)
International Scoping Study of a future
Neutrino Factory and Superbeam Facility
(Jan. 23-25, 2006 KEK)
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Contents of my talk
1, Introduction of flavor and CP violation in
MSSM 2, Probe models beyond MSSM by charged
lepton- flavor violation 3, Furthermore probe the
models by flavor physics 4, Summary
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1, Introduction
Flavor and/or CP violating processes are a
traditional window for new physics and the
studies are complementary to new particle
searches in collider physics.
B/D/K meson systems neutrino
oscillation muon/tau lepton
flavor-violating decays leptonic and hadronic
electric dipole moments
Minimal Supersymmetric Standard Model (MSSM)
Nowadays, MSSM is the most well-motivated model

• Solution of the hierarchy problem.
• Consistent with Grand Unified Theories (GUTs).
• Lightest SUSY particle is good dark matter
  candidate.
• Light Higgs boson predicted.

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Flavor physics plays an important role in
construction and establishment of MSSM.
Introduction of SUSY breaking for squarks and
sleptons leads to new flavor and CP violation.
SUSY
SUSY
mixing and give
stringent constraints on structure of SUSY
breaking.
Universal scalar mass hypothesis
Alignment hypothesis
Decoupling hypothesis
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Universal scalar mass in minimal supergravity
model
(Gravity mediation of SUSY breaking)
MSSM
Radiative correction due to gauge interaction
Slepton mass matrices are almost flavor-blind.
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Universal scalar mass in minimal supergravity
model
Models beyond MSSM might have new flavor and/or
CP violating interactions. Seesaw mechanism
SUSY GUTs
SUSY GUTs
Seesaw
LFV
MSSM
We might probe models beyond MSSM from studies of
flavor and CP violations.
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Summary of Introduction
New Source for flavor/CP violation in MSSM
SUSY breaking terms
We may probe from studies for flavor and/or CP
violating processes i) Origin of the SUSY
breaking terms in MSSM ii) Physics in models
beyond MSSM (ex, Seesaw mechanism, SUSY
GUTs, etc ) Lepton flavor violation might be
more sensitive to them since squark mass terms
receive larger flavor-independent correction from
QCD.
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2, Probe models beyond MSSM by charged
lepton-flavor violation
Neutrino oscillation Finite, but small neutrino
mass
Seesaw mechanism (Introduction of
right-handed neutrinos )
Baryon in Universe Leptogenesis (B-L violation
by Majorana mass )
Unification of Matter in SO(10) GUT
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Neutrino-oscillation v.s. charged lepton-flavor
violation

• Light neutrino mass matrix

• Neutrino Yukawa coupling induces LFV left-handed
  slepton mass
• terms

i) Charged LFV and neutrino-oscillation gives
independent information about seesaw
mechanism. ii) Large mixing angles, observed in
the neutrino osc. exp., might enhance charged
lepton flavor violation.
(UMNS matrix)
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Charged lepton-flavor violation in seesaw mechanim
Babbar(05), 710-8
Super B factory
MEG
PRISM (mu-e conv.)
(JH, Kakizaki, Nagai, Shimizu)

• Measurement of Ue3 gives impact on charged LFV
  prediction.
• mu-gte gamma and mu-e conversion searches might
  probe
• struture of the seesaw mechansim.

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Supersymmetric SU(5) Ground Unification
Matter unification of quarks and leptons
In MSSM with right-handed neutrinos, In
SUSY SU(5) GUT with right-handed neutrinos,
quarks and leptons are unified, and then
CKM mixing ? Left-handed sdown
mixing Neutrino mixing ? Left-handed slepton
mixing
CKM mixing ? Right-handed slepton
mixing Neutrino mixing ? Right-handed sdown
mixing
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mu-gt e gamma in SUSY SU(5) GUTs
Orbifold model
Minimal model
(JH)
(JH, Kakizaki, Nagai)
Minimal model predicts small branching ratio due
to smaller interaction, CKM mixing, and
accidental cancellation. However, it is not end
of the story since we have to care some illnesses
of the minimal model.
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3, Furthermore probe the models by flavor physics
P-odd asymmetry in mu-gte gamma
When is discovered, the polarized
muon experiment gives a chance to probe the
origin.

• left-handed slepton mixing, such as in seesaw.

• right-handed slepton mixing, such as in SUSY
  SU(5) GUTs

Leptonic EDMs
When both left- and right-handed sleptons have
mixings, the relative phases contribute to
leptonic EDMs. (Ex. SUSY SU(5) GUTs with )
Due to similarity of the one-loop diagrams
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Correlation between hadronic and leptonic flavor
violation
Leptonic and hadonic flavor violations are
correlated to each other in SUSY GUTs.
Ex,
b-s quark mixing
CP asymmetry in versus
in SUSY SU(5) GUT with
right-handed neutrinos
Experimental bound
(JH, Shimizu)
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4, Summary of my talk

• Flavor and/or CP violating processes are a
  traditional window for new physics and the
  studies are complementary to new particle
  searches in collider physics. Nowadays, MSSM is a
  well-motivated model. We may probe origin of the
  SUSY breaking and physics in models beyond MSSM
  from the studies. Especially, charged LFV is more
  sensitive to beyond MSSM, such as seesaw and SUSY
  GUTs.
• Charged LFV search is expected to probe the
  seesaw mechanism and to play a complementary role
  to the neutrino oscillation. Measurement of Ue3
  is important in order to make prediction for
  mu-gte gamma more precise.
• SUSY GUTs also provide other LFV interaction
  source. While the minimal model predicts small
  Br(mu-gte gamma), the realistic extension might
  enhance it.
• When charged LFV is discovered, P-odd asymmetry
  in mu-gte gamma, leptonic EDMs, and hadonic flavor
  violation will give insight for the sources.