Exploring SUSY models through quark and lepton flavor physics

1
Exploring SUSY models through quark and lepton
flavor physics

• Yasuhiro Okada(KEK/Sokendai)
• June 18, 2008
• SUSY 2008, Seoul, Korea

2
Content of this talk

• 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,
  arXiv0711.2935

3
Flavor in the LHC era

• 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.
• 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.
• New flavor experiments are coming. LHCb, B
  physics at ATLAS and CMS, MEG, Super B, etc.

4
SM has a characteristic feature among various
flavor and CP signals.
EDM 0
Lepton flavor Neutrino mixing LFV0
Quark flavor B,D,K
Relationship may be quite different for new
physics contributions.
5
The Unitarity Triangle
Even if CKM looks perfect, there are still room
for new physics contributions of at least a few
10s .
Fit by tree level processes
SM global fit
6
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 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
7
Rare B decays Various tests of new physics

• S(B-gtfKs)
• Time-dependent CP asymmetry of
  penguin-dominated processes
• A(b-gtsg)
• Direct CP asymmetry of b-gtsg
• S(B-gtKg)
• Time-dependent CP asymmetry of B-gt Kg
• AFB(b-gtsll), AFB(B-gtKg)
• Forward-backward asymmetry of b-gtsll, B-gtKll
• B(B-gt tn),B(B-gt Dtn)

New phase
Right-handed operator
charged Higgs exchange
8
Expected precisions at Super B factory
Super KEKB study and SuperB CDR study 50-75 ab-1

Current results
0.39 0.17
b-s transition
0.61 0.07
0.58 0.20
Charged Higgs
error 0.05-0.06
EW penguin
-0.09 0.24
0(10) physics (Now) gt 0(1) physics (Future)
CERN Flavour WS report arXiv0801.1833   
9
CPV in Bs system at LHCb

• Measurement of CP violation in the Bs system is a
  major goal of the LHCb experiment.
• Many are parallel to the Bd system.

2fb-1 (1year)
M.Merk,a talk at CERM TH Institute, May 26,2008
10
m and t Lepton Flavor Violation
B( t-gtmg)

• Sensitive to slepton flavor mixings
• The MEG experiment will search for B(m-gteg) 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.

S.Banerjee, TAU 06
Super B factory, 50-75 ab-1
arXiv0801.1833   
11
SUSY and flavor physics

• 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
12
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?
13
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, arXiv0711.2935

• 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.

• Observables
• Bd-Bd mixing, Bs-Bs mixing.
• CP violation in K-K mixing (e).
• Time-dependent CP violation in B -gtJ/yKs, B-gtfKs,
  B-gtKg ,B-gtrg.
• Direct CP violation in b-gts g,b-gtdg
• m-gteg, t-gtmg, t-gteg

• Models
• 1. Minimal supergravity model (mSUGRA)
• 2. SUSY seesaw model
• 2. SU(5) SUSY GUT with right-handed neutrino
• MSSM with U(2) flavor symmetry

14
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.
Neutrino Yukawa coupling
Quark Yukawa coupling
Interactions at GUT/seesaw scale
Lepton flavor violation in m-gteg t-gtmg t-gteg
Quark flavor signals Time-dep CP asymmetries in
B-gtfKs B -gt Kg Bs-gtJ/yf
L.J.Hall,V.Kostelecky,S.Raby,1986A.Masiero,
F.Borzumati, 1986, R.Barbieri,L.Hall,1994,
R.Barbieri,L.Hall.A.Strumia, 1995,
S.Baek,T.Goto,Y.O, K.Okumura, 2001T.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
15
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 anglegt m-gteg enhanced
16
If is somewhat suppressed,
the B(m-gteg) 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 q130.

We consider various cases for heavy neutrino and
light neutrino mass hierarchy.
17
Degenerate MN (4x1014 GeV) q13 0
SUSY Seesaw model (without GUT)
Normal hierarchy
Degenerate (mn10.1eV)
Inverse hierarchy
t-gtmg
m-gteg
t-eg
m-eg is promising signal in the normal hierarchy
case, and t-gtmg 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
18
SU(5) SUSY GUT
Degenerate MN and Normal hierarchy for light
neutrinos
B(m-gteg) can be close to the present bound even
if the slepton mass is 3 TeV.
Contour in the m0 -M1/2 plane
m-gteg, t-gtmg, t-gteg branching ratios
m-gteg bound
19
Lepton Flavor Violation in the non-degenerate MN
case
t-gtmg
t-gtmg, t-gteg vs. m-gteg
B(t-gtmg)
B(m-gteg)
m-gteg
t-gteg
20
Time-dependent CP violation in Bd decays
S(Bd-gtKg)
DS S(B-gtfKs)-S(B-gtJ/yKs)
Super B
Super B
These asymmetries can be sizable if the squarks
are within the LHC reach.
21
Time-dependent CP asymmetry in Bs -gt J/yf
S(Bs-gtJ/yf)
S(Bs-gtJ/yKs) vs. B(t-gtmg)
SuperB
LHCb
Recent works on Bs mixing J.K. Parrym H-H. Zhong
2007 B.Dutta, Y.Mimura2008 J.Hisano Y.Shimizu,
2008.
22
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 .

• The quark Yukawa couplings and the squark mass
  terms are governed by the same flavor symmetry.
• 1st and 2nd generation gt U(2) doublet
• 3rd generation gt U(2) singlet

We do not consider LFV processes in this model
23
Various CP asymmetries are possible for the b-s
and b-d transitions in the U(2) model
A( b-gtsg)
S(Bd-gtKg)
S(Bs-gtJ/yf)
S(Bd-gtrg)
24
Summary table of flavor signals for mSUGRA, SUSY
seesaw, SUSY GUT, MSSA with U(2) flavor symmetry
Pattern of deviation from the SM predictions are
different for various cases considered.
25
Conclusions

• 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.