Measurements of f 1 / b and f 2 / a

Measurements of Measurements of 11// and and 22//

Masashi Hazumi (KEK)Masashi Hazumi (KEK)

July 31, 2006XXXIII International Conference on High Energy Physics (ICHEP’06)

Many thanks to many people, in particular to: T. Aushev, T. Browder, P. Chang, R. Faccini, K. George, T. Gershon, K. Hara, H. Ishino, A. Lazzaro, S. Olsen, Y. Sakai, O. Tajima and K. Trabelsi

2

New ResultsNew Results fromfrom BaBarBaBar andand Belle Bellefor Stringent Tests of the for Stringent Tests of the

Kobayashi-Maskawa Model of Kobayashi-Maskawa Model of CPCP Violation Violation

3

Main New Results Covered in This TalkMain New Results Covered in This Talk(all results are preliminary)(all results are preliminary)

• 11 with tree diagram (b with tree diagram (b ccsccs))• BaBar: sin2BaBar: sin2 in in BB00 J/ J/(2S)(2S)KKSS, , ccKKSS, , c1c1KKSS, J/, J/

• Belle: sin2Belle: sin211 in in BB00 J/ J/

• 11 with penguin diagram ( with penguin diagram (bb sqqsqq))• BaBar: BaBar: BB00 KK++KKKK00, , ’’KK00, , KKSSKKSSKKSS, , KKSS, , KKSS, , 00KKSS

• Belle: Belle: BB00 ’’KK00 , ,00KKSS

• Belle: Belle: BB00 KK00, , KK++KKKKSS , , KKSSKKSSKKSS , , f f 00KKSS, , KKSS

• 2 2

• BaBar: BaBar: , , , , • Belle: Belle: • Belle: Belle:

K.HaraK.Hara

K.GeorgeK.George

A. LazzaroA. Lazzaro

O. TajimaO. Tajima

This talkThis talk

This talkThis talk

H. IshinoH. Ishino

S. TelnovS. Telnov

4

• Some other new results and recently published results also mentioned but very briefly.

• /3-related R.Kowalewski (next speaker)

• My apologies if your favorites are not included

RemarksRemarks

5

2525thth Anniversary of Anniversary of Time-dependent Time-dependent CPCP Violation (t Violation (tCPCPV)V)

6

Tony, are you nuts?

Look at this.

We need millions of B

and use them to

search for mixing and CP violation

This took us six months!

Tributefrom S. Olsen

5 B mesons

7

PEP-II at SLAC

KEKB at KEK

Belle

BaBar

9GeV (e) 3.1GeV (e+)peak luminosity:

1.121034cm2s1

Two Asymmetric-energy Two Asymmetric-energy BB Factories Factories

8GeV (e) 3.5GeV (e+) peak luminosity:

1.651034cm2s1

world record

11 nations, 80 institutes, 623 persons

13 countries, 57 institutes, ~400 collaborators

8

Integrated LuminosityIntegrated Luminosity

PEP-IIfor BaBar

As of July 24, 2006

KEKBfor Belle

KEKB + PEP-II

9

• Far beyond the design luminosities of both proposals• Triumph in accelerator science

reached on July 13, 2006

~ 1 Billion BB pairs

10

MotivationMotivationQ. What is the main source of CP violation ?

A. Kobayashi-Maskawa phase IS the dominant source !

Two promising approaches1) Overconstrain the unitarity triangle: precise measurements of and needed2) Compare sin2 in tree diagram and penguin diagram (e.g. b s)

sin2 history(1998-2005)

Q. Are there deviations from the CKM picture ? (e.g. new CP-violating phases)

Paradigm shift !

11

11

12

Time-dependent Time-dependent CPCP violation (t violation (tCPCPV)V)“double-slit experiment” with particles and antiparticles“double-slit experiment” with particles and antiparticles

b c

d

csd

J/KS

b

d cJ/KS

bcsddt

t

+

Quantum interference between two diagrams

tree diagram box diagram + tree diagramVtd

Vtd

You need to “wait” (i.e. t0) to have the box diagram contribution.

You need to “wait” (i.e. t0) to have the box diagram contribution.

13

ttCPCPV in BV in B00 decays decays

(A = C a la BaBar)

Mixing-induced CPVMixing-induced CPV Direct CPVDirect CPV

e.g. for J/ KsS = CPsin21 = +sin21 A = 0to a good approximation(CP : CP eigenvalue)

e.g. for J/ KsS = CPsin21 = +sin21 A = 0to a good approximation(CP : CP eigenvalue)

14

)cossin(141

,1 tmAtmSetqPt

)21( w

R

R : detector resolutionw : wrong tag fraction (misidentification of flavor) (1-2w) quality of flavor tagging They are well determined by using control sample D*l D(*) etc…

S = 0.65A = 0.00 B0 tag

_B0 tag

B0 tag_B0 tag

-CPsin21

Mixing of D*lGood tag region(O

F-SF

)/(O

F+SF

)

t| (ps)

15

11 with trees with trees

- Results -- Results -

16

BB00 J/ J/ K K00 : 535 M BB pairs : 535 M BB pairs

2*/

2*KsJbeambc PEM

B0 J/ KS B0 J/ KL

Nsig = 7482Purity 97 %

CP odd

Nsig = 6512Purity 59 %

CP even

pKL information is poor lower purity

Belle preliminary

0 0

__

BELLE-CONF-0647BELLE-CONF-0647

O. TajimaO. Tajima

17

B0 J/ KS

B0 tag_B

0 tag

0 B0 J/ KL

B0 tag_B0 tag

0

Asym. = -CPsin21sinmt

sin21= +0.643 ±0.038 A = - 0.001 ±0.028

sin21= +0.641 ±0.057 A = +0.045 ±0.033

stat error stat error


O. TajimaO. Tajimabackgroundsubtracted

18

B0 J/ KS

B0 tag_B

0 tag

0 B0 J/ KL

B0 tag_B0 tag

0

B0 tag_B

0 tag

BB00 J/ J/ K K00 : combined result : combined result

Asym. = -CPsin21sinmt

sin21= +0.643 ±0.038 A = - 0.001 ±0.028

sin21= +0.641 ±0.057 A = +0.045 ±0.033

stat error stat error


O. TajimaO. Tajima

19

BB00 J/ J/ K K00 : combined result : combined result

sin21= 0.642 ±0.031 (stat) ±0.017 (syst) A = 0.018 ±0.021 (stat) ±0.014 (syst)

previous measurementsin2= 0.652 0.044

(388 M BB pairs)

B0 tag_B

0 tag

535 M BB pairs_ _

Belle preliminary BELLE-CONF-0647BELLE-CONF-0647

O. TajimaO. Tajima

20

K.GeorgeK.George

A = 0.07 0.028 0.018

BaBar2006: sin2BaBar2006: sin2 in b in b ccs ccs

BB00 J/ J/(2S)(2S)KKSS, , ccKKSS, , c1c1KKSS, , J/J/

21

2006: BaBar + Belle2006: BaBar + Belle

Consistency with Vub, 3/ R. Kowalewski (next speaker)

22

(not sin2(not sin2) measurements) measurements

B0D*+D*KsTime-dependent Dalitz analysis (T.Browder, A. Datta et al. 2000) cos2 > 0(94%CL, model-dependent)

B0Dh0 (h0 = 0 etc.)Time-dependent Dalitz analysis cos2 > 0Belle: 98.3%CL(hep-ex/0605023, accepted by PRL)BaBar 87% CL (BABAR-CONF06/017)

K.GeorgeK.George

23

11 with penguins with penguins

24

3 theoretically-clean modesKs, ’Ks, 3Ks

25

Results for Results for 3 theoretically-clean modes3 theoretically-clean modes

KK00, , ''KK00, KsKsKs, KsKsKs

26

Belle 2006: Belle 2006: BB00 KK0 0 signalsignal

B0 mass

B0 momentum

_535M BB

(bkg subtracted)

KK, KS

KK, KS

KSKL, KS

114 17 KL signal

114 17 KL signal

307 21 KS signal

307 21 KS signal

Three modes

New !


27

Belle 2006: tBelle 2006: tCPCPV in V in BB00 KK00

“sin21” = 0.50 0.21(stat) 0.06(syst) A = 0.07 0.15(stat) 0.05(syst)


KS and KL combined background subtracted good tags t –t for KL

t distribution and asymmetry

_535M BB

Consistent with the SM (~1lower) Consistent with Belle 2005

(Belle2005: “sin21” = +0.44

The most precise measurement now

Consistent with the SM (~1lower) Consistent with Belle 2005

(Belle2005: “sin21” = +0.44

The most precise measurement now

unbinned fitSM


28

BaBar 2006: tBaBar 2006: tCPCPV in V in BB00 KK00

• Obtain CP parameters for 2-body and 3-body modes simultaneously by time-dependent Dalitz fit

_347M BB

KKKS

KKKS

KKKL

1516 65 KKK0signal

1516 65 KKK0signal

29K0: sin2eff = +0.12 ± 0.31(stat) ± 0.10 (syst)K0: sin2eff = +0.12 ± 0.31(stat) ± 0.10 (syst)

BaBar 2006: tBaBar 2006: tCPCPV in V in BB00 KK00

measurement (not sin2)

Rejected(within SM)4.6

30

Belle 2006: Belle 2006: BB00 ''KK0 0 signalsignal

1421 46 'KS signal

1421 46 'KS signal

454 39 'KL signal

454 39 'KL signal

_535M BB

(bkg subtracted)B0 massB0 momentum

31

Belle 2006: tBelle 2006: tCPCPV in V in BB00 ''KK00



_535M BB

First observation of tCPV (5.6in a single b s mode

Consistent with the SM Consistent with Belle 2005

(Belle 2005: “sin21” = +0.62

First observation of tCPV (5.6in a single b s mode

Consistent with the SM Consistent with Belle 2005

(Belle 2005: “sin21” = +0.62


''KS and ''KL combined background subtracted good tags t –t for ''KL BELLE-CONF-0647BELLE-CONF-0647

32

BaBar 2006: tBaBar 2006: tCPCPV in V in BB00 ''KK00

Cf. BaBar 2005: “sin2” = +0.36 0.13 0.03

“sin2” = 0.55 0.11(stat) 0.02(syst) A = 0.15 0.07(stat) 0.03(syst) “sin2” = 0.55 0.11(stat) 0.02(syst) A = 0.15 0.07(stat) 0.03(syst)

“sin2” 4.9 from zero.

_347M BB

33

Belle 2006: tBelle 2006: tCPCPV in V in BB00 KKSSKKSSKKSS



185 17 KSKSKS signal


B0 mass

_535M BB


background 　　 subtracted good tags


34


BaBar 2006: tBaBar 2006: tCPCPV in V in BB00 KKSSKKSSKKSS




_347M BB

35

Results for other b Results for other b s modes s modes(~20sec/result)(~20sec/result)

36

Belle 2006: tBelle 2006: tCPCPV in V in BB00 ff00KKSS

“sin21” = 0.23(stat) 0.11(syst) A = 0.15(stat) 0.07(syst)


_535M BB

377 25 f0KS signal377 25 f0KS signal

Raw symmetryB0 mass

good tags mass


37

BaBar 2006: tBaBar 2006: tCPCPV in V in BB00 KKSS


425 280KS signal

425 280KS signal

_347M BB

38

Belle 2006: tBelle 2006: tCPCPV in V in BB00 KKSS



_535M BB

515 320KS signal

515 320KS signal

Raw symmetryB0 mass

good tags


39

Belle 2006: tBelle 2006: tCPCPV in V in BB00 KKKKKKSS

“sin21” = 0.15(stat) 0.03(syst) (CP-even) A = 0.10(stat) 0.05(syst)

“sin21” = 0.15(stat) 0.03(syst) (CP-even) A = 0.10(stat) 0.05(syst)

_535M BB

840 34 KS signal

840 34 KS signal

Raw symmetry

B0 mass

good tags

+0.210.13


40

Belle 2006: tBelle 2006: tCPCPV in V in BB00 KKSS



_535M BB

118 18 KS signal

118 18 KS signal

B0 mass

Raw symmetry

good tags


41


“sin2” = 0.62 (stat) 0.02(syst) A = 0.43 (stat) 0.03(syst) “sin2” = 0.62 (stat) 0.02(syst) A = 0.43 (stat) 0.03(syst) +0.23

0.25

+0.250.30

142 17 0KS signal142 17 0KS signal

_347M BB

42



111 19KS signal

111 19KS signal

quasi 2-body approach (restricting tothe region dominated by 0)

_347M BB

43

2006: 2006: 11 with with bb ss Penguins PenguinsSmaller than bccs in all of 9 modes

Smaller than bccs in all of 9 modes

Theory tends to predictpositive shifts(originating from phasein Vts)

Naïve average of all b s modes

sin2eff = 0.52 ± 0.052.6 deviation betweenpenguin and tree (b s) (b c)

Naïve average of all b s modes

sin2eff = 0.52 ± 0.052.6 deviation betweenpenguin and tree (b s) (b c)

More statistics crucial for mode-by-mode studies

44

Standard penguin (bird), or something else (rabbit may be) ?

More statistics crucial for mode-by-mode studies

45

Other handles to search for new physicsOther handles to search for new physicswith penguin diagrams with penguin diagrams

• B0 KsKs (b d penguin): even higher statistics needed

• B sum rule [Gronau, Rosner 2005]• A(K00) = A(K) + A(K0+) – A(K+0)

• B0 Ks0 (electromagnetic penguin)• New physics may lead to right handed currents. This can be

investigated using time-dependent CPV measurements of b s decays and will be discussed in Barlow's talk.

S ~ 0 expected in SM

0.120.110.160.04

46

22

1 “beam”1 “beam”

2 “banana”2 “banana”

47

ttCPCPV and V and 2 2 (())

13

2VudV*ub

VtdV*tb

VcdV*cb

B0

d

b–

d–

bt

–tB0

–V*

tb Vtd

V*tbVtd

Mixing diagram Decay diagram (tree)

B0

b–

d du–

d–u

/

/Vud

V*ub

With the tree diagram only

S = +sin22

A = 0

S = +sin22

A = 0

3 possibilities: 3 possibilities:

48

Belle 2006: B0→+− decay (CP asymmetry)

04.010.061.0

05.008.055.0

S

A

first error: stat., second: syst.

background subtracted

+−

yie

lds

+−

asy

mm

etr

y

Large Direct CP violation (5.5)

Large mixing-induced CP violation (5.6)

confidence level contour

H. IshinoH. Ishino

BELLE-CONF-0649BELLE-CONF-0649 _535M BB

1464±65 signal events

49

S. TelnovS. Telnov

BaBar 2006: tBaBar 2006: tCPCPV in V in BB00

confidence level contour

Evidence for CP violation (3.6)

Direct CP violation not yet observed

02.014.053.0

03.011.016.0

S

A

50

History of B0→+− decay

2.3 diff. btw. Belle and BaBar

(C = A)

51

The results support the expectation from SU(3) symmetry that

)(3~)( KAA CPCP

018.0115.0)( KACPHFAG summer 2005

Interpretation: Direct CP violation+SU(3)

N.G. Deshpande and X.-G. He, PRL 75, 1703 (1995)

M. Gronau and J.L. Rosner, PLB 595, 339 (2004)

3.0~)( CPA

ICHEP2006 World Average

07.039.0~)( CPA

52

:tough bananas:tough bananas

• A world average observation of large direct CPV• Large penguin diagram (P) ~ Tree diagram (T)• Large strong phase difference between P and T

B0d

d

b

du

u

W

g +

-

VtdV*

tb

t d

2222 )2sin(1 effeffAS 2222 )2sin(1 effeffAS

53

Isospin analysis: flavor SU(2) symmetryIsospin analysis: flavor SU(2) symmetry

• Model-independent (symmetry-dependent) method• SU(2) breaking effect well below present statistical errors

2222 )2sin(1 effeffAS 2222 )2sin(1 effeffAS“Penguin pollution” can be removed by isospin analysis“Penguin pollution” can be removed by isospin analysis

[Gronau-London 1990]

54

2 constraints from B0→+− decay

inputsB(+0) = (5.75 0.42)B(+-) = (5.20 0.25) 10-6

B(00) = (1.30 0.21) A(00) = +0.35 0.33S(+-) = 0.59 0.09A(+-) = +0.39 0.07

inputsB(+0) = (5.75 0.42)B(+-) = (5.20 0.25) 10-6

B(00) = (1.30 0.21) A(00) = +0.35 0.33S(+-) = 0.59 0.09A(+-) = +0.39 0.07

No stringent constraintobtained with system alone need and

55

ttCPCPV with BV with B00

• Even worse on first sight ...– Dirty final state: – Mixture of CP = +1 and 1: need to know each fraction

(A++A-)/√2

A||

(A+-A-)/√2

A⊥

A0

+

+A0

A+

A-

+1

1

1

CP

vector vector

56

Isospin analysis with B Isospin analysis with B • Branching fraction for B0 is larger than

• Branching fraction for B0 is small (<1.1x10-6)– small penguin pollution

• ~100% longitudinally polarized (~pure CP-even state)– no need for elaborate angular analysis

• No significant 3-body/4-body contamination

• Dirty final states including 0

– OK in the clean e+e environment

the best mode as of summer 2005the best mode as of summer 2005

57

BaBar2006: tBaBar2006: tCPCPV in B V in B

58

BaBar2006: B BaBar2006: B (cont.)(cont.)

• B0 branching fraction: indication at 3.0

• B+ branching fraction

59

2 constraints from B0→+− decay

New branching fraction

Isospin triangle now closed (new )

constraint on 2 becomes less stringent.

60

BaBar2006: B BaBar2006: B Dalitz analysis Dalitz analysis

Preliminary result in 2004 (16 parameters ignoring ) is superseded.

Interferenceinfo. onstrong phasedifference

B0

B0

61

ICHEP2006: BaBar(ICHEP2006: BaBar(////) + Belle() + Belle(//))

Global Fit = [ 98 ] º +5-19

/2 = [93 ]+119 consistent with a global fit w/o /2

62

• sets a “window” around 90• chooses the correct position inside

the window: revival of ! • essential to suppress 2~ 0 or 180

• Good agreement b/w the CKM fit ( determined by others) and the direct measurements

• Still a lot to do– solution around 0 or 180, which requires |P/T|~1, can/should be much more

suppressed • e.g. Model-independent constraint using K* (robust against SU(3) breaking)

[Beneke-Gronau-Rohrer-Spranger 2006]– subtleties in statistical analyses with small statistics– uncertainty in background modeling, unknown phases etc.

//22: Discussions: Discussions

63

Belle 2006: Belle 2006: 22 from B from B Dalitz analysis + isospin (pentagon) analysis Dalitz analysis + isospin (pentagon) analysis

• 26(Dalitz) + 5(Br(), Br(), Br(), A(), and A())

2 (degree)

1-C

L

Results

mass

helicity

/2 = [83 ]+12 (1)

(no constraint at 2

will be included in the world averageBELLE-CONF-0650BELLE-CONF-0650

_449M BB

64

SummarySummary

• ttCPCPV allows a direct access to fundamental EW parameters V allows a direct access to fundamental EW parameters with small hadronic uncertainties in spite of large hadronic with small hadronic uncertainties in spite of large hadronic uncertainties in branching fractions !uncertainties in branching fractions !

• sin2sin211 now determined with 4% accuracy now determined with 4% accuracy• ttCPCPV in b V in b s: interesting (and tantalizing) hint of deviation from SM s: interesting (and tantalizing) hint of deviation from SM

expectations: only an order of magnitude more data will resolve the expectations: only an order of magnitude more data will resolve the issueissue

• With improved statistics and sophisticated analyses, it has become With improved statistics and sophisticated analyses, it has become clear that clear that 22 is harder to determine than we thought at ICHEP2004; is harder to determine than we thought at ICHEP2004; however, statistics are still the main obstacle.however, statistics are still the main obstacle.

My talk is just a status report !The best of two B factories is yet to come !

My talk is just a status report !The best of two B factories is yet to come !

tCPV Beautyin

Backup SlidesBackup Slides

66

Both Both 11// and and 22// Determined from Determined from

Measurements ofMeasurements ofTime-dependent Time-dependent CPCP Asymmetries Asymmetries

in the in the BB Meson System Meson System

67

Belle 2006: Systematic errors of BBelle 2006: Systematic errors of B00J/J/KK00

Sin21 A

Vertexing 0.012 0.009

Flavor tagging 0.004 0.003

t Resolution 0.006 0.001

Physics parameters. 0.001 0.001

Possible fit bias 0.007 0.004

BG fractions (J/KS) 0.003 0.001

BG fractions (J/KL) 0.005 0.002

BG t 0.001 0.001

Tag-Side interference 0.001 0.009

total 0.017 0.014

68

J/K0

J/KS

J/KL

q=+1q=-1

SVD1SVD2

ntrktag>=6ntrktag=5ntrktag=4ntrktag=3ntrktag=2ntrktag=1

r0.875-1.0000.750-0.8750.625-0.7500.500-0.6250.250-0.5000.100-0.250

69

KEKB Integrated luminosity

B0 J/ KS0

B0 J/ KL0

70

2006: World Average2006: World Average

0.6750.026

71

2006: BaBar + Belle2006: BaBar + Belle

No direct CPV in the SM: will see with more data No direct CPV in the SM: will see with more data

~2 differenceb/w BaBar and Belle

72

BaBar:

statistical error: 0.034 0.026

More precisemeasurementspossible withmore data !

More precisemeasurementspossible withmore data !

K.GeorgeK.George

73

Belle 2006: Belle 2006: BB00 KKSS helicityhelicity

_532M BB

Consistent with the model used in the analysis [P-wave () + small non P-wave component obtained from Dalitz analysis]

Consistent with the model used in the analysis [P-wave () + small non P-wave component obtained from Dalitz analysis]

74

Belle 2006: tBelle 2006: tCPCPV in V in BB00 KK00 _532M BB

KSKS KL

KL

“sin21” = +0.500.23(stat)“sin21” = +0.500.23(stat) “sin21” = +0.460.56(stat)“sin21” = +0.460.56(stat)

75

Belle 2006: tBelle 2006: tCPCPV in V in BB00 ''KK00 _532M BB

'KS'KS 'KL

'KL

“sin21” = +0.670.11(stat)“sin21” = +0.670.11(stat) “sin21” = +0.480.24(stat)“sin21” = +0.480.24(stat)

76


“sin21” with subsamples“sin21” with subsamples

Errors are statistical only

77


Significance of tCPVSignificance of tCPV

S = 0 ruled outwith >5.6at any A

78

79

80

B0→+− decay

C =−A

2.3 diff. btw. Belle and BaBar

81

82

83

84

(1.4 b/w BaBar and Belle)

85

86

87

88

UTfit: UTfit: from from , , , ,

All combined

More SlidesMore Slides

90

The Kobayashi-Maskawa weak phaseThe Kobayashi-Maskawa weak phase

(0,0) (0,1)

_ _(, )

1()3()

2()

Normalized with |VcdVcb*|

= (12/2)

= (12/2)

100

010

001

CKMCKM VV

In particular, Vtd = |Vtd|exp(i1) Vub = |Vub|exp(i3)

A3

3 generations CP-violating phase3 generations CP-violating phase

91

What’s What’s CPCP violation ? violation ?It is a partial rate asymmetry !It is a partial rate asymmetry !

|B |f

1 = |1|eisei

2 = |2|eis’ei’

)'cos()'cos(||||2||||

)'sin()sin(|||2

)()(

)()(22 ss

ss

fBfB

fBfB

Asym

|B |f

1 = |1|eisei

2 = |2|eis’ei’

CP

’: weak phase diff. : previous slide ss’: static phase diff. : FSI, Resonance, m

’: weak phase diff. : previous slide ss’: static phase diff. : FSI, Resonance, m

92

Wolfenstein parameterizationWolfenstein parameterization

93

Inclusive e’s Inclusive e’s at the at the ϒϒ(4S)(4S)

2.0 2.2 2.4 2.6

Belle

CLEO result in ~1980

Tributefrom S. Olsen

94

Back to the FutureBack to the Future1981 1981 2006 2006

95

PEP-II

KEKB

Belle

BaBar

9GeV (e) 3.1GeV (e+)peak luminosity: 1.121034cm2s1

Two Asymmetric-energy Two Asymmetric-energy BB Factories Factories

8GeV (e) 3.5GeV (e+) peak luminosity: 1.651034cm2s1

world record !

Charged tracking/vertexingCharged tracking/vertexing • • SVD:SVD:

(-7/03) 3-layer DSSD Si µstrip(-7/03) 3-layer DSSD Si µstrip (8/03-) 4-layer(8/03-) 4-layer • • CDC: 50 layers (He-ethane)CDC: 50 layers (He-ethane)

Hadron identificationHadron identification • • CDC: dE/dxCDC: dE/dx • • TOF: time-of-flightTOF: time-of-flight • • ACC: Threshold Cerenkov ACC: Threshold Cerenkov

(aerogel)(aerogel)Electron/photonElectron/photon • • ECL: CsI calorimeterECL: CsI calorimeter

Muon/KMuon/KLL • • KLM: Resistive plate KLM: Resistive plate

counter/ironcounter/iron

Charged tracking/vertexingCharged tracking/vertexing • • 5-layer DSSD Si µstrip5-layer DSSD Si µstrip • • 40 layers (He-isobutane)40 layers (He-isobutane)

Hadron identificationHadron identification • • tracker: dE/dxtracker: dE/dx • • DIRC imaging Cerenkov DIRC imaging Cerenkov

Electron/photonElectron/photon • • CsI calorimeterCsI calorimeter

Muon/KMuon/KLL • • Instrumented flux returnInstrumented flux return

96

PEP-II & BaBarPEP-II & BaBar• Lmax = 1.12 X 1033 cm–2s–1

Ldt = 371 fb–1@{Υ(4S)+off(~10%)}• (>3.7x108 B events)

Charged tracking/vertexingCharged tracking/vertexing • • 5-layer DSSD Si µstrip5-layer DSSD Si µstrip • • 40 layers (He-isobutane)40 layers (He-isobutane)

Hadron identificationHadron identification • • tracker: dE/dxtracker: dE/dx • • DIRC imaging Cerenkov DIRC imaging Cerenkov

Electron/photonElectron/photon • • CsI calorimeterCsI calorimeter

Muon/KMuon/KLL • • Instrumented flux returnInstrumented flux return

11 nations, 80 institutes, 623 persons

97

e+ source

Ares RF cavity

Belle detector

World record: L = 1.6 x

1034/cm2/sec

SCC RF(HER)

ARES(LER)

The KEKB ColliderThe KEKB Collider

8 x 3.5 GeV 22 mrad crossing angle

~1 km in diameter

Mt. Tsukuba

KEKBBelle

since 1999

http://jp.f35.mail.yahoo.co.jp/ym/ShowLetter/ringanimation2M.gif?box=Inbox&MsgId=2406_9445966_98224_1696_384623_0_1738_499387_3403004772&bodyPart=1.4&filename=ringanimation2M.gif&tnef=&YY=43275&order=down&sort=date&pos=0&view=a&head=b

http://kekb.jp/

98

Belle detectorBelle detector

KL detector14/15 layer RPC+Fe

Electromagnetic CalorimeterCsI(Tl) 16X0

Aerogel Cherenkov Counter n = 1.015~1.030

Si Vertex Detector4-layer DSSD

TOF counter

3.5 GeV e+

Central Drift Chamber momentum, dE/dx 50-layers + He/C2H6

charged particle tracking

K/ separation

K/ separation

B vertexMuon / KL identification

, 0 reconstructione+-, KL identification

8.0 GeV e-

99

= 0.425 (Belle) 0.56 (BaBar)

Principle of tPrinciple of tCPCPV measurementV measurementCP-side

1. Fully reconstruct one B-meson which decays to CP eigenstate

electron

positron

(4S)resonance B1

B2

+

-

KS/L

J/

100

= 0.425 (Belle) 0.56 (BaBar)

Principle of tPrinciple of tCPCPV measurementV measurement

t z c

CP-side

Flavor tag and vertex reconstr

uction

Flavor tag and vertex reconstr

uction

1. Fully reconstruct one B-meson which decays to CP eigenstate2. Tag-side determines its flavor (effective efficiency = 30%)3. Proper time (t) is measured from decay-vertex difference (z)

electron

positron

(4S)resonance B1

B2

+-

K+

-0

D

+

-

KS/L

J/

z ~ 200m(Belle)

B0

B0_

101

b g s modes and their “cleaness” in SMb g s modes and their “cleaness” in SM

taken from a review “CP violation” in PDG2005 (D.Kirkby, Y.Nir)

pure treeb cud DCP 0 DCPKs (Vcb*Vud)T + (Vub*Vcd)T 2

+ ucd

102

Experimental ChallengeExperimental Challenge

B0 J/KS

B0 KS

Tree

Penguin

We need1) large number of BB pairs2) additional background rejection

Event Shape Event Shape

e e qq

(Jet-like)e e 4 S B B

(Spherical)

Mbc

Signal Likelihood

103

Signal Likelihood (LHR) projection

Mbc projection

LHRMbc

Clear separation betweensignal and background

Clear separation betweensignal and background

BB00 KsKs

Ks signal

Ks signal

Documents

Measurements of f 1 / b and f 2 / a