Exploring SUSY models through quark
and lepton flavor physics
Yasuhiro Okada(KEK/Sokendai)
June 18, 2008
SUSY 2008, Seoul, Korea
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Content of this talk
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Quark and lepton flavor physics processes
sensitive to the TeV scale physics.
Study of quark and lepton flavor signals in
various cases of SUSY models.
T.Goto,Y.O., T.Shindou,M.Tanaka, arXiv:0711.2935
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Flavor in the LHC era
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LHC will give a first look at the TeV scale physics.
The mass of the Higgs boson alone is an important hint for
possible new physics scenarios.
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Flavor structure of the TeV scale physics is largely
unknown.
Patterns of the deviations from the SM predictions are a key to
distinguish new physics models.
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New flavor experiments are coming. LHCb, B
physics at ATLAS and CMS, MEG, Super B, etc.
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SM has a characteristic feature among various flavor and CP signals.
EDM ~0
SUSY CP
Quark flavor
Lepton flavor
Neutrino mixing
B,D,K
LFV~0
slepton mixing
GUT
Relationship may be quite different for new physics contributions.
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The Unitarity Triangle
Even if CKM looks perfect, there are still room for
new physics contributions of at least a few 10’s %.
SM global fit
Fit by tree level processes
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Improvement on f3/g is essential
In order to disentangle new physics effects, we first need to
determine the CKM parameter by tree processes.
Expected precision
|Vub|, f3/g
+
Bd mixing and CP asymmetries
+
Bs mixing and CP asymmetries
+
eK and B(K->pnn)
LHCb
5-10 deg (2fb-1: 1year)
Super B factory
1-2 deg (50-75 ab-1)
We know (or constrain) which sector is affected by new physics
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Rare B decays: Various tests of new physics
New phase
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S(B->fKs)
Time-dependent CP asymmetry of
penguin-dominated processes
New phase
A(b->sg)
Direct CP asymmetry of b->sg
Right-handed operator
S(B->K*g)
Time-dependent CP asymmetry of
B-> K*g
AFB(b->sll), AFB(B->K*g)
Forward-backward asymmetry of bcharged Higgs exchange
>sll, B->K*ll
b
n
B(B-> tn),B(B-> Dtn)
H-
u
t
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Expected precisions at Super B factory
Super KEKB study and SuperB CDR study; 50-75 ab-1
Current results
b-s
transition
0.39 ± 0.17
0.61 ± 0.07
0.58 ± 0.20
Charged
Higgs
error ~0.05-0.06
EW
penguin
0(10%) physics (Now)
=> 0(1%) physics (Future)
−0.09 ± 0.24
CERN Flavour WS report: arXiv:0801.1833
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CPV in Bs system at LHCb
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Measurement of CP violation in the Bs system is a
major goal of the LHCb experiment.
Many are parallel to the Bd system.
Time dep. CP in Bs->J/yf
“Bs mixing phase”
Time-dep. CPV in Bs-> ff
“b-s penguin phase”
Time-dep. CPV in Bs->fg
“right-handed current”
2fb-1 (1year)
S(Bd->J/y Ks)
S(Bd->fKs)
S(Bd->K*g)
M.Merk,a talk at CERM TH Institute, May 26,2008
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m and t Lepton Flavor Violation
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Sensitive to slepton flavor mixings
The MEG experiment will search for
B(m->eg) up to 10-13. The current
upper bound is 1.2 x 10-11.
One to two orders improvements
are expected at a Super B factory
for tau LFV searches.
B( t->mg)
S.Banerjee, TAU 06
Super B factory, 50-75 ab-1
arXiv:0801.1833
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SUSY and flavor physics
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LHC experiments will be a crucial test for existence of
SUSY. (Squark/gluino mass reach 2-3 TeV, A light Higgs
boson)
The role of flavor physics is to determine the flavor
structure of squark/slepton mass matrixes. (new sources
of flavor mixing and CP phases)
Squark/slepton mass matrixes carry information of
SUSY breaking mechanism and interactions at high
energy scale (ex. GUT/Planck scale).
Diagonal tem: LHC/LC
Off diagonal term:
Flavor Physics
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Different assumptions on the SUSY
breaking sector
Minimal Flavor Violation (ex. mSUGRA)
SUSY GUT with see-saw neutrinos
SUSY breaking
Flavor symmetry
Effective SUSY
etc.
How to distinguish these models from factory observables?
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Quark and lepton flavor physics in various SUSY models
T.Goto, Y.O. Y.Shimizu, T.Shindou, and M.Tanaka,2002, 2004
T.Goto,Y.O., T.Shindou,M.Tanaka, arXiv:0711.2935
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In order to illustrate how future flavor experiments are
useful to distinguish different SUSY models, we
calculated various quark and lepton flavor observables in
representative SUSY models.
Models
1. Minimal supergravity
model (mSUGRA)
2. SUSY seesaw model
2. SU(5) SUSY GUT with
right-handed neutrino
3. MSSM with U(2) flavor
symmetry
Observables
 Bd-Bd mixing, Bs-Bs mixing.
 CP violation in K-K mixing (e).
 Time-dependent CP violation
in B ->J/yKs, B->fKs, B>K*g ,B->rg.
 Direct CP violation in b->s g,b>dg
 m->eg, t->mg, t->eg
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mSUGRSA with GUT/Seesaw Yukawa interaction
Yukawa interactions at the GUT scales induce quark and lepton flavor signals.
In the SU(5) setup, the right-handed sdown sector can receive flavor mixing
due to the neutrino Yukawa couplings.
Quark Yukawa coupling
Neutrino Yukawa coupling
Interactions
at GUT/seesaw scale
Quark flavor signals
Time-dep CP asymmetries in
B->fKs
B -> K*g
Bs->J/yf
Lepton flavor violation in
m->eg
t->mg
t->eg
L.J.Hall,V.Kostelecky,S.Raby,1986;A.Masiero, F.Borzumati, 1986, R.Barbieri,L.Hall,1994,
R.Barbieri,L.Hall.A.Strumia, 1995, S.Baek,T.Goto,Y.O, K.Okumura, 2001;T.Moroi,2000;
A.Masiero, M.Piai,A Romanino, L.Silvestrini,2001 D.Chang, A.Masiero, H.Murayama,2003
J.Hisano,and Y.Shimizu, 2003, M.Ciuchini, et.al, 2004, 2007…
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Effects of the neutrino Yukawa coupling
Neutrino mass matrix (in the basis where yl is diagonal).
LFV mass terms for slepton (and sdown).
LFV mass terms and VPMNSis directly related when
(Minimal LFV)
Large solar mixing angle=> m->eg enhanced
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If
is somewhat suppressed, the B(m->eg) constraint
becomes weaker, and a variety of flavor signals are possible.
• Non-degenerate MN
J.Casas, A.Ibarra2001; J.Ellis,J.Hisano,M.Raidal,Y.Shimizu, 2002
• Degenerate MN, but inverse hierarchy or degenerate light neutrino with q13~0.
We consider various cases for heavy neutrino and light neutrino mass hierarchy.
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SUSY Seesaw model (without GUT)
Normal hierarchy
t-eg
t->mg
Inverse hierarchy
Degenerate MN (=4x1014 GeV)
q13 =0
Degenerate (mn1=0.1eV)
m->eg
m-eg is promising signal in the normal hierarchy case, and t->mg can be also
large in other cases :
Recent related works: L.Calibim, A.Faccica A.Masiero, S.K.Vepati, 2006
L.Calibim, A.Faccica A.Masiero, 2006
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SU(5) SUSY GUT
Degenerate MN and “Normal hierarchy” for light neutrinos :
B(m->eg) can be close to the
present bound even if the
slepton mass is 3 TeV.
Contour in the m0 -M1/2 plane
m->eg, t->mg, t->eg branching ratios
m->eg bound
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Lepton Flavor Violation in the non-degenerate MN case
t->mg
B(t->mg)
t->mg, t->eg vs. m->eg
t->eg
m->eg
B(m->eg)
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Time-dependent CP violation in Bd decays
DS= S(B->fKs)-S(B->J/yKs)
Super B
S(Bd->K*g)
Super B
These asymmetries can be sizable if the squarks are within the LHC reach.
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Time-dependent CP asymmetry in Bs -> J/yf
S(Bs->J/yf)
S(Bs->J/yKs) vs. B(t->mg)
SuperB
LHCb
Recent works on Bs mixing:
J.K. Parrym H-H. Zhong 2007; B.Dutta, Y.Mimura2008; J.Hisano Y.Shimizu, 2008.
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MSSM with U(2) flavor symmetry
A.Pomarol and D.Tommasini, 1996; R.Barbieri,G.Dvali, and L.Hall, 1996; R.Barbieri and L.Hall;
R.Barbieri, L.Hall, S.Raby, and A.Romonino; R.Barbieri,L.Hall, and A.Romanino 1997;
A.Masiero,M.Piai, and A.Romanino, and L.Silvestrini,2001; ….
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The quark Yukawa couplings and the squark mass
terms are governed by the same flavor symmetry.
1st and 2nd generation => U(2) doublet
3rd generation => U(2) singlet
We do not consider LFV processes in this model
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Various CP asymmetries are possible for the b-s and b-d transitions in the U(2) model
A( b->sg)
S(Bd->rg)
S(Bd->K*g)
S(Bs->J/yf)
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Summary table of flavor signals for mSUGRA, SUSY seesaw, SUSY GUT,
MSSA with U(2) flavor symmetry
LFV
b-s and b-d transitions
Pattern of deviation from the SM predictions are different for various cases considered.
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Conclusions
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We have performed a comparative study on quark
and lepton flavor signals for representative SUSY
models; mSUGRA, MSSM with right-handed
neutrinos, SU(5) SUSY GUT with right-handed
neutrinos, and U(2) models.
Each model predicts a different pattern of the
deviations from the SM in b-s and b-d quark
transition processes and muon and tau LFV
processes.
These signals can provide important clues on
physics at very high energy scales if SUSY particles
are found at LHC.
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