1. Exploring SUSY breaking mechanism with B decays
Yasuhiro Okada (KEK)
At 4th workshop on higher luminosity B factory, KEK, February4, 2003

2. New Physics search at SuperKEKB
A main motivation for SuperKEKB is to search for new sources of CP violation and flavor mixings.
In SUSY models, B physics is important to study SUSY breaking scenario through squark mass matrices.
Patten of deviation from the SM provide information on SUSY breaking mechanism.

3. Supersymmetry (SUSY)
SUSY was introduced as a part of extension of the Poincare algebra (extension of the space-time concept)
SUSY introduces a superpartner for each particle (quark - squark; lepton – slepton, etc)
Remarkable cancellation occurs in the renormalization of scalar mass terms (A solution of the hierarchy problem in the SM)

4. SUSY Model
Three gauge coupling constants are nicely unified for SUSY GUT.
SUSY search will be carried out at TEVATRON, LHC, and a future linear collider.
Mass spectrum provides a hint for SUSY breaking.

5. Role of Flavor Physics
Determine flavor structure of squark mass matrices.
Quark mass -> Yukawa coupling Squark mass -> SUSY breaking terms
SUSY breaking terms carry information on GUT/Planck scale interactions.
Diagonal tem: LHC/LC
Off diagonal term:
Flavor Physics

6. B physics in three SUSY models
In order to illustrate how B physics is useful to explore the SUSY breaking sector, we take three models T.Goto, Y.Okada, Y.Shimizu, T.Shindou, and M.Tanaka
Minimal supergravity model
SU(5) SUSY GUT with right-handed neutrino
MSSM with U(2) flavor symmetry

7. Minimal supergravity model
All squarks are degenerate at the Planck scale.
Flavor mixings and mass-splittings are induced by renormalization.
As a consequence,
The CKM matrix is the only source of flavor mixing.

8. SU(5) SUSY GUT with right-handed neutrino
Large flavor mixing in the neutrino sector can be a source of flavor mixing in the right-handed squark sector (Correlation with LFV processes )

9. MSSM with U(2) flavor symmetry
The quark Yukawa couplings and the squark mass terms are governed by the same flavor symmetry.

10. Numerical results
We calculated SUSY effects to the following observables in the three models.
CP violation in K-K mixing.
Bd-Bd mixing, Bs-Bs mixing.
Mixing-induced CP violation in B ->J/yKs,
B->fKs, B->Ms g .
Direct CP violation in b->s g.

11. Unitarity Triangle mSUGRA 1. Minimal SUGRA:
The deviation from the SM is less than 10%.
2. SUSY GUT with nR :
(MR ij= d ij)
Bs-mixing can be different from the SM.
B-unitarity triangle is closed.
3. U(2) flavor symmetry:
Large SUSY corr. to K, Bd, and Bs mixings.
B-unitarity triangel may not be closed.
GUT+nR
Bs-mixing
U(2) FS f3
A(B->J/yKs)

12. f3 determination (a) (c)
Even if Bs-mixing is consistent with the SM, f3 measurement could show the deviation for the U(2) model.
gluino mass

13. CP asymmetry in B ->fKs
If there are new phases other in the b-to-s transition,
the CP asymmetry can be different from that of
The B ->J/yKs mode.
SUSY GUT (MR:general)
mSUGRA
U(2) symmetry
A(B->fKs)
gluino mass
(preliminary)

14. Mixing-induced asymmetry in B->Msg
Signal of b->sgR ; Large for SU(5) SUSY GUT with a general from of the right-handed neutrino mass matrix, and the U(2) flavor symmetry model.
SUSY GUT+nR
U(2) flavor symmetry
A(B->Msg)
gluino mass
Stop masss
(preliminary)

15. Direct CP asymmetry of b->s g
A signal of new phases in the b -> s g transition.
The deviation can be large for the U(2) model.
SUSY GUT +nR
mSUGRA
U(2) flavor symmetry
A(b->sg)
Stop mass

16. Pattern of the deviation from the SM prediction
Bs mixing
Bd unitarity
B->fKs
B->Msg indirect
b->sg direct
mSUGRA
small
closed
SU(5) SUSY GUT
(MR=1)
large
possible
(MR=general)
(closed)
U(2) flavor symmetry

17. Summary
If SUSY is a true symmetry of Nature, the determination of the SUSY breaking scenario is one of the most fundamental issues. (Generation of the weak scale, information on interactions at the Planck/GUT/neutrino scales, possible new source of CP violation.)
We expect different patterns of deviations from SM predictions in flavor physics for different SUSY breaking scenarios.
Physics at SuperKEKB is therefore essential to discriminate various SUSY breaking scenarios.