Future Prospects for B Physics at a Super B Factory

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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

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We have done quite well so far ...
PEPII,KEK-B both exceeded design lum. 0.8
ab-1total
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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
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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.
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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).

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

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Super KEK-B

• Luminosity 41035/cm2s
• 40KEKB design luminosity (25achieved peak)
• 5109 BB pairs/yr
• 4109 tt pairs/yr, 5109 cc pairs/yr
• A super B factory is a super tau-charm factory
• LOI in 2004
• http//belle.kek.jp/superb/loi
• Physics at Super B Factory hep-ex/0406071
• Official Budget request submitted to Japanese
  government in Aug 2005.
• (Not approved yet)

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In order to increase the luminosity. . .
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Super KEK-B Upgrades
Interaction Region Crab crossing q30mrad. by
3mm New QCS
New Beam pipe
More RF power
Damping ring
Linac upgrade
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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 ....)

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Time-dependent decay distribution on Y4S
H. Miyake
A
S
A -C
S Dtasymmetry, A tag area difference
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Current status of b?sqq
S - xfsin2f1 for J/YKS,L (xf CP
eigenvalue) Define sin2f1eff - xfS D sin2f1eff
sin2f1eff -sin2f1
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b?sqq at Super B Factory
summer 2005
50ab-1
assuming present WA
?S(fKs) at 50ab-1 XX ?0.03(stat) ? 0.01(syst)
?0.04(th)
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fKs
How can it constrain theories?
Summer 2005
Mass matrix elements between and are
constrained.
based on S.Khalil and E.Kou PRD67, 055009
(2003) and SuperKEKB LoI
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fKs
Theory may need some mechanism to explain
suppressed d or f
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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)
• S0.5 is allowed

s
g
b
X
X
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tCPV in B? Ksp0g
Belle (386M BB pairs) use Ks vertex for Dt
S 0.080.410.10 (MXlt1.8 GeV)
consistent with zero
SM S -2 ms/mb sin2f1 0
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CPV in b g s and SUSY models (Super B)
S(Ksp0)Kg 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

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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
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AFB(ll) in b?sll Sensitivities
Sensitivity at Super KEKB
Experimental results with 0.35 ab-1
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.
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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.
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Search for LFV in t decays

• SUSY Seesaw, or GUT
• Large LFV possible

Br(t?mg)O(10-79)
mSUGRA
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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
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More tests of SUSY breaking scenarios
T.Goto, Y.Okada, Y.Shimizu,T.Shindou, M.Tanaka
(2002, 2004) SuperKEKB LoI
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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
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Unitarity triangle at 50ab-1
It may not close. Something new in loops!
Triangle closes, or...
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DNA Identification of BSMby Flavor Physics
Unitarity triangle
Rare decays
Bd- unitarity e D m(Bs) B-gtfKs B-gtMsg indirect CP b-gtsg direct CP
mSUGRA - - - - -
SU(5)SUSY GUT nR (degenerate) - - -
SU(5)SUSY GUT nR (non-degenerate) - -
U(2) Flavor symmetry
Large, sizable, - small
Okada et al (2004).
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Comparison with LHCb
SuperKEKB
5ab-1
50ab-1
LHCb 2fb-1
CPV (b g s)
FCNC
w/ n
CKM
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Advantages of Super B Factory

• B decays with neutrinos B g Dtn, tn, uln
  etc.
• B decays with g, p0 B g Xsg, p0p0 etc.
• B vertex reconstruction with Ks only !
• B g Ksp0, Ksp0g etc.

Dtn etc.
B meson beam !
B
e- (8GeV)
e(3.5GeV)
?(4S)
p
B
full (0.10.3) reconstruction BgDp etc.
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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.

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Back Ups
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Hint of Problems?
Limited by statistics at the moment.
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Direct CP Violation
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Projection of integrated luminosity

• Crab cavity installation in 2006
• 2?109 BB pairs by 2008 (4?now)
• Long shutdown (14months) in 2009-2010
• Constant improvement from 2010
• realistic and reliable plan based on experiences
  at KEKB
• Crab cavities well tested before 2010 a big
  advantage !

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Bkg TRG rate in future
x20 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 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