1. Future Prospects for B Physics at a Super B Factory
M. Hazumi
M. Yamauchi
T. Browder
and many others
Thanks to:
Hitoshi Yamamoto
Tohoku University
DIF06, Frascati, March 2, 2006

2. We have done quite well so far ...
PEPII,KEK-B both exceeded
design lum. ~0.8 ab-1total
Evidence for direct CP
violation in B g K+p-
Observation of CP violation
in B meson system

3. Main Aim of B-factories : To test the CKM mechanism of CPV
CPV by the irreducible complex phases in quark-W coupling:
V: CKM matrix
Unitarity of V
(Unitarity triangle)
Measure the sides and angles in different modes

4. Status of Unitarity Triangle
(Normalized to the length of the bottom)
Summer 2005
‘Lines’ by sin2b, eK,
Vub/Vcb. a, g, and Dms,d
all cross at a single point!
Striking confirmation
of the CKM paradigm.
A part of SM.

5. Problems of Standard Model
Quadratic divergence of Higgs mass correction.
Indicates new physics in TeV scale.
SUSY? Little Higgs?
Pattern of CKM matrix is not explained.
Underlining mechanism by new physics implied.
Why 3 generations?
Cannot explain the matter excess of universe.
CKM not enough. Other source of CPV implied.
Does not have dark matter candidates
WMAP : ~1/4 of universe is dark matter
Implies new particles (e.g. SUSY has).

6. New Physics : New Flavor Structure
Standard Model quark-W coupling
Left-handed coupling only
Pattern of Cabibbo suppressions in CKM matrix
No additional CPV phases
New flavor structures
Could be right-handed
Pattern of mixing matrix element different from CKM
New CPV phases
High-luminosity
Flavor physics
Mass matrix
(general)
Energy frontiers
(LHC, ILC)

7. For example : MSSM
Down type squark mass matrix
Super B factory

8. Need for a Super B Factory
New flavor physics would be likely to appear in loops of b→s,d transitions.
B→s,d transitions currently limited by statistics.
Increasing the statistics by ~100 (thereby reducing the error by 1/10) is imperative.
→ Super B-factory.
Preparations/studies underway in Japan, US, and Europe.

9. Super KEK-B Luminosity ~ 4×1035/cm2s LOI in 2004
40×KEKB design luminosity (25×achieved peak)
5×109 BB pairs/yr
4×109 tt pairs/yr, 5×109 cc pairs/yr
A super B factory is a super tau-charm factory
LOI in 2004
“Physics at Super B Factory” hep-ex/
Official Budget request submitted to Japanese government in Aug 2005.
(Not approved yet)

10. SuperKEKB
41035 cm-2s-1

11. In order to increase the luminosity. . .

12. Super KEK-B Upgrades Interaction Region Crab crossing New Beam pipe
q=30mrad.
by*=3mm
New QCS
New Beam pipe
More RF power
Damping ring
Linac upgrade

13. Probes for New Flavor Structure
New CPV phase in b→sqq
Time-dependent CPV analsysis (tCPV)
Right-handed current in b→sg
tCPV
Lepton AFB in b→sll
LFV in t decays
Charged Higgs in B → Dtn, tn
...and many more
(b→snn, mm, nn, gg ....)

14. Time-dependent decay distribution on Y4S
H. Miyake A S
A = -C
S: Dt±asymmetry, A: tag area difference

15. Current status of b→sqq
S= - xfsin2f1 for J/YKS,L
(xf : CP eigenvalue)
Define sin2f1eff= - xfS
D sin2f1eff = sin2f1eff -sin2f1

16. bsqq at Super B Factory
SM predictions
DSfK0 (July 2005)
summer 2005
DSfK0 (SuperKEKB)
50ab-1
assuming
present WA
∆S(fKs) at 50ab-1
= XX 0.03(stat)  0.01(syst) 0.04(th)

17. fKs How can it constrain theories? Summer 2005 Mass matrix elements
between and
are constrained.
based on
S.Khalil and E.Kou
PRD67, (2003)
and SuperKEKB LoI

18. fKs
Theory may need some
mechanism to explain suppressed d or f

19. Right-handed current in bsg
In SM, s is left-handed → g is left-handed.
In the CP conjugate mode,
g is right-handed.
Flavor-specific →no tCPV.
(suppression factor ~ms/mb)
In BSM, s may be right handed.
→ tCPV
LRSM, SUSY, Randall-Sundrum, etc.
* LRSM: SU(2)LSU(2)RU(1)
S~0.5 is allowed g b s X X

20. tCPV in B→ Ksp0g Belle (386M BB pairs) : use Ks vertex for Dt
S = 0.08±0.41± (MX<1.8 GeV)
consistent with zero
SM : S = -2 ms/mb sin2f1 ~ 0

21. CPV in b g s and SUSY models (Super B)
S[(Ksp0)K*g] error = 0.5(now) → 0.14(5ab-1)
T.Goto, Y.Okada, Y.Shimizu,T.Shindou, M.Tanaka (2002, 2004) + SuperKEKB LoI
Expected precision at 5ab-1
Correlations are useful to differentiate new physics models

22. AFB(ll) in b→sll Polarization of ll system
(or whatever is creating it)
+L/R couplings to l → AFB(ll)
l +
l -
b quark
s quark ?
sensitive to new physics :
SUSY, heavy Higgs and extra dim.
SM and
SUSY models
AFB
SM also has large
Asymmetry :
Z-g interference
S(ll) = q2

23. AFB(ll) in b→sll : Sensitivities
Experimental results with 0.35 ab-1
Sensitivity at Super KEKB
Belle, 2005
Standard model
MC, 50 ab-1
Zero-crossing q2 for AFB will be
determined with 5% error.
Belle, 2005
Control sample B→Kll
Helicity(ll system) = 0
→ No FB asymmetry.

24. AFB(ll) in b→sll : now G(q2,cosq) : function of A7, A9, A10
These (radical) models are already excluded by recent data from Belle.

25. Search for LFV in t decays
SUSY + Seesaw, or GUT
Large LFV possible
BR(tgmg) ~10-6  tan2b
(mL2)32
mL2 ~
( ) 4
1 TeV
mSUSY
Br(tmg)=O(10-7~9)
mSUGRA

26. Search for LFV in t decays
Well within range!
SUSY t→mg
Present limit
Super-B limit
tlg
tlp/h/h’
t3l
tl Ks
tBg/p
Gaugino mass = 200GeV

27. More tests of SUSY breaking scenarios
S(K*g)
S(fKs)
Br(b g sg)
A(b g sg)
AFB(b g sll)
Br( t g mg)
50ab-1
T.Goto, Y.Okada, Y.Shimizu,T.Shindou, M.Tanaka (2002, 2004) + SuperKEKB LoI

28. Sensitivity for Charged Higgs
Constraint from BXs g
BDtn
D(Form-factor) ~5%
D(Form-factor) ~15%
Btn
(present)
LHC
100fb-1

29. Unitarity triangle at 50ab-1
It may not close.
Something new in loops!
Triangle closes, or...

30. DNA Identification of BSM by Flavor Physics
Unitarity triangle
Rare decays
Bd- unitarity e
D m(Bs)
B->fKs
B->Msg indirect CP
b->sg direct CP
mSUGRA - +
SU(5)SUSY
GUT + nR
(degenerate)
(non-degenerate) ++
U(2) Flavor symmetry
++: Large, +: sizable, -: small
Okada et al (2004).

31. Comparison with LHCb SuperKEKB 5ab-1 50ab-1 LHCb 2fb-1 FCNC CKM w/ n
CPV (b g s)
FCNC
w/ n
CKM

32. Advantages of Super B Factory
B decays with neutrinos B g Dtn, tn, uln etc.
B decays with g, p B g Xsg, p0p0 etc.
B vertex reconstruction with Ks only !
B g Ksp0, Ksp0g etc.
Dtn etc.
B meson beam ! B
Charged Higgs
Vub
e- (8GeV)
e+(3.5GeV)
Υ(4S) p B
full (0.1~0.3%)
reconstruction
BgDp etc.
direct CPV
f2(a) isospin analysis
p+ p-
Ks trajectory
IP profile
B vertex g

33. Summary
B-factories have been successful, and now beginning to probe new physics.
Many new physics are well within reach of Super B factory.
Super B factory can distinguish various BSM models.
New particles that would be discovered at LHC/ILC will be tested/measured in their flavor sector.
Super B factory is sensitive to mass scale beyond the reach of LHC/ILC.

34. Back Ups

36. Hint of Problems? Limited by statistics at the moment. tree penguin B0
fL (B→VV) ~ 1 in SM
tree
penguin
ACP(B→Kπ) is equal
between B± and B0. B0 B±
Limited by statistics at the moment.

37. Direct CP Violation

38. Projection of integrated luminosity
Crab cavity installation in 2006
~2109 BB pairs by 2008 (4now)
Long shutdown (14months) in
Constant improvement from 2010
realistic and reliable plan based on experiences at KEKB
Crab cavities well tested before 2010: a big advantage ! 5 4 3 2 1
NBB (1010)
We are here.
NBB ~100  now !
in the LHC era

39. Bkg & TRG rate in future x20 Bkg x10 Bkg KEKB Bkg KEKB SuperB
Luminosity
(1034cm-2sec-1) ~1 40
HER curr. (A)
LER curr. (A)
vacuum (10-7Pa)
1.2
1.6
~1.5
4.1
9.4 5
Bkg increase -
x 20
TRG rate (kHz)
phys. origin
Bkg origin
0.4
0.2 14 10 4
x10 Bkg
KEKB
Bkg
SVD
CDC
PID / ECL
KLM
Synchrotron radiation
Beam-gas scattering (inc. intra-beam scattering)
Radiative Bhabha