Future Prospects for B Physics at a Super B Factory

Hitoshi YamamotoTohoku University

DIF06, Frascati, March 2, 2006

Thanks to:

M. HazumiM. YamauchiT. Browder and many others

Observation of CP violation in B meson system

Observation of CP violation in B meson system

Evidence for direct CP violation in B K+

Evidence for direct CP violation in B K+

We have done quite well so far ...

PEPII,KEK-B both exceededdesign lum. ~0.8 ab-1total

Main Aim of B-factories :To test the CKM mechanism of CPV

€

Vaba Lγμ bL W μ (a = u,c, t; b = d, s,b)

CPV by the irreducible complex phases in quark-W coupling:

€

α /φ2 ≡ argVtdVtb

*

−VudVub*

, β /φ1 ≡ argVcdVcb

*

−VtdVtb*

, γ /φ3 ≡ argVudVub

*

−VcdVcb*

Unitarity of V(Unitarity triangle)

Measure the sides and angles in different modes

V: CKM matrix

Status of Unitarity Triangle

Summer 2005

‘Lines’ by sin2 Vub/Vcb. α and ms,d all cross at a single point!

Striking confirmationof the CKM paradigm. A part of SM.

(Normalized to the length of the bottom)

■ 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).

Problems of Standard Model

■ 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

New Physics : New Flavor Structure

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m112 m12

2 m132 m14

2

m212 m22

2 m232 m34

2

m312 m32

2 m332 m34

2

m412 m42

2 m432 m44

2

⎛

⎝

⎜ ⎜ ⎜ ⎜

⎞

⎠

⎟ ⎟ ⎟ ⎟

Mass matrix(general)

High-luminosityFlavor physics

Energy frontiers(LHC, ILC)

For example : MSSM

Super B factory

Down type squark mass matrix

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.

Super KEK-B

■ Luminosity ~ 4cm2s◆ 40KEKB design luminosity (25achieved peak)◆ 5 BB pairs/yr◆ 4 pairs/yr, 5 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)

SuperKEKB41035 cm2s1

In order to increase the luminosity. . .

Interaction RegionCrab crossing

=30mrad.y*=3mm

New QCS

Linac upgrade

More RF power

Damping ring

New Beam pipe

Super KEK-B Upgrades

Probes for New Flavor Structure

■ New CPV phase in b→sqqTime-dependent CPV analsysis (tCPV)

■ Right-handed current in b→stCPV

■ Lepton AFB in b→sll■ LFV in decays■ Charged Higgs in B → D ■ ...and many more b→s

Time-dependent decay distribution on Y4S

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ACP (Δt)

S

A

€

ΓB,B (Δt)∝ e−γ |Δt|[1± (S sin ΔmΔt + AcosΔmΔt)]

S: t±asymmetry, A: tag area difference

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B, B

A C

H. Miyake

Current status of b→sqq

S= fsin2 for J/KS,L

f : CP eigenvalue)Define sin2

eff= fS sin2

eff sin2eff sin2

bbsqq at Super B Factorysqq at Super B Factory

SM predictions

SK0 (July 2005)

SK0 (SuperKEKB)50ab-1

summer 2005

∆S(Ks) at 50ab1

= XX 0.03(stat) 0.01(syst) 0.04(th)

∆S(Ks) at 50ab1

= XX 0.03(stat) 0.01(syst) 0.04(th)

assumingpresent WA

KsKsSummer 2005

based onS.Khalil and E.Kou PRD67, 055009 (2003)and SuperKEKB LoI

How can it constrain theories?

Mass matrix elementsbetween andare constrained.

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˜ s L,R

€

˜ b R,L

KsKs

Theory may need somemechanism to explain suppressed or

Theory may need somemechanism to explain suppressed or

Right-handed current in bs ■ In SM, s is left-handed → is left-handed. In the CP conjugate mode, 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)LSU(2)RU(1)

S~0.5 is allowed

sb

XX

tCPV in B→ KsBelle (386M BB pairs) : use Ks vertex for t

S = 0.08±0.41±0.10 (MX<1.8 GeV) consistent with zero

SM : S = -2 ms/mb sin2

CPV in b s and SUSY models (Super B)

■ Correlations are useful to differentiate new physics models■ Correlations are useful to differentiate new physics models

Expected precision at 5ab

T.Goto, Y.Okada, Y.Shimizu,T.Shindou, M.Tanaka (2002, 2004) + SuperKEKB LoI

S[(Ks error = 0.5(now) → 0.14(5ab-1)

AFB(ll) in b→sll

?b quark s quark

l l

sensitive to new physics : SUSY, heavy Higgs and extra dim.

Polarization of ll system(or whatever is creating it)+L/R couplings to l → AFB(ll)

S(ll) = q2

AFB

SM and SUSY models

SM also has large Asymmetry : Z- interference

AFB(ll) in b→sll : Sensitivities

MC, 50 ab-1

Experimental results with 0.35 ab-1

Belle, 2005

Standard model

Sensitivity at Super KEKB

Zero-crossing q2 for AFB will be determined with 5% error.

Control sample B→KllHelicity(ll system) = 0 → No FB asymmetry.

Belle, 2005

These (radical) models are already excluded by recent data from Belle.

AFB(ll) in b→sll : now

Γq2,cos function of A7, A9, A10

Search for LFV in decays

■ SUSY + Seesaw, or GUTLarge LFV possible

Br()=O(10-7~9)BR() ~10-6 tan2(mL

2)32

mL2

~

~( ) 41 TeVmSUSY

mSUGRA

Search for LFV in decays

0tanâ=30,A=0,ì>0

Gaugino mass = 200GeV

Present limit Super-B limit

l

l’

3l

l Ks

B

Well within range!SUSY →

More tests of SUSY breaking scenarios

S(K*)

S(Ks)

Br(b s)

A(b s)

AFB(b sll)

Br( )S(Ks)

50ab-1 A(b s)Br(b s)

AFB(b sll)

T.Goto, Y.Okada, Y.Shimizu,T.Shindou, M.Tanaka (2002, 2004) + SuperKEKB LoI

Sensitivity for Charged Higgs

(Fo

rm-f

acto

r) ~

5%

(For

m-facto

r) ~15

%

BD

B (present)

Constraint from BXs

LHC100fb-1

Unitarity triangle at 50ab-1

Triangle closes, or...

It may not close.Something new in loops!

DNA Identification of BSMby Flavor Physics

Bd- unitarity

m(Bs) B->Ks B->Ms indirect CP

b->s direct CP

mSUGRA - - - - - +SU(5)SUSY GUT + R

(degenerate)- + + - + -

SU(5)SUSY GUT + R

(non-degenerate)- - + ++ ++

+

U(2) Flavor symmetry + + + ++ ++ ++

++: Large, +: sizable, -: small

Unitarity triangle Rare decays

Okada et al (2004).

Comparison with LHCb

SuperKEKB 5ab-1 50ab-1 LHCb 2fb-1

CK

Mw

/ F

CN

CC

PV

(b s

)

Advantages of Super B Factory

■ B decays with neutrinosB D, , ul etc.

■ B decays with , 0

B Xs, 00 etc.

■ B vertex reconstruction with Ks only ! B Ks0, Ks0 etc.

Ks trajectory IP profileB vertex

Υ(4S)e (8GeV)

e+(3.5GeV)

B

B

full (0.1~0.3%)reconstructionBD etc.

full (0.1~0.3%)reconstructionBD etc.

D etc.D etc.B meson beam !B meson beam !

Charged HiggsCharged Higgs VubVub

direct CPVdirect CPV 2(α) isospin analysis2(α) isospin analysis

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.

Back Ups

Hint of Problems?fL (B→VV) ~ 1 in SM

treepenguin

Limited by statistics at the moment.Limited by statistics at the moment.

ACP(B→Kπ) is equalbetween B± and B0.

B0

B±

Direct CP Violation

Projection of integrated luminosity

■ Crab cavity installation in 2006

■ ~2109 BB pairs by 2008 (4now)

■ 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 !

We are here.We are here.

5

4

3

2

1N

BB

(10

10)

NBB ~100 now !in the LHC era

NBB ~100 now !in the LHC era

Bkg & TRG rate in future

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

0.40.2

0.2

1410

4

Synchrotron radiationBeam-gas scattering (inc. intra-beam scattering)Radiative Bhabha

SVD CDC PID / ECL KLM

KEKBBkg

x10 Bkg

x20 Bkg