1 measurements with tree-level processes at belle o. tajima (kek) belle collaboration ichep06 july...

11 measurements with measurements with tree-level processestree-level processes

at Belleat Belle

O. Tajima (KEK)Belle collaboration

ICHEP06 July 28, 2006

2

Kobayashi-Maskawa PhaseKobayashi-Maskawa Phase

CP violation parameters(1, 2, 3) = (, , )

~ 0.22CP violation is due to a complex phase

in quark mixing matrix

3

_

d

b_ c

csd

_wB0J/

K0

sin2sin211 measurement measurement

V*td

V*td_ _

tdtb

b

d _ww B0B0

_

B0

B0qp

fCP

=A CP (t ; B0J/K0) (t ; B0J/K0)

(t ; B0J/K0) (t ; B0J/K0)

_

_

= -cpsin21 sin(mt) + A cos (mt) Mixing induced CPV Direct CPV (A = C)

CP : CP eigenvalue, +1 (-1) for CP even (odd)

A=0

4

= 0.425 (Belle) 0.56 (BaBar)

Principle of TCPV measurementPrinciple of TCPV measurementCP-side

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

electron(8GeV)

positron(3.5GeV)

(4S)resonance B1

B2

+

-

KS/L

J/

5

= 0.425 (Belle) 0.56 (BaBar)

Principle of TCPV measurementPrinciple of TCPV measurement

t z c

CP-side

Flavor tag and vertex reconstr

uction

1. Fully reconstruct one B-meson which decays to CP eigenstate2. Tag-side determines its flavor3. Proper time (t) is measured from decay-vertex difference (z)

electron(8GeV)

positron(3.5GeV)

(4S)resonance B1

B2

+-K+

-0

D

+

-

KS/L

J/

z ~ 200m(Belle)

B0

B0_

6

KEKB KEKB : the highest luminosity in the world: the highest luminosity in the world

3.5 GeV e+ 8.0 GeV e

ee (4S) with = 0.425

22 mrad crossing angle

Located in Tsukuba, Japan

Lpeak = (1.651034)/cm2/sec ~ 1M BB pairs/day

integrated luminosity = 0.63 /ab

532 M BB pairs analysisare shown, today

_

_

Belle detector

7

International Collaboration: BelleInternational Collaboration: Belle

13 countries, 55 institutes, ~400 collaborators

IHEP, ViennaITEPKanagawa U.KEKKorea U.Krakow Inst. of Nucl. Phys.Kyoto U. Kyungpook Nat’l U. EPF Lausanne Jozef Stefan Inst. / U. of Ljubljana / U. of MariborU. of Melbourne

Aomori U.BINPChiba U.Chonnam Nat’l U.U. of CincinnatiEwha Womans U.Frankfurt U.Gyeongsang Nat’l U.U. of HawaiiHiroshima Tech.IHEP, BeijingIHEP, Moscow

Nagoya U.Nara Women’s U.National Central U.Nat’l Kaoshiung Normal U.National Taiwan U.National United U.Nihon Dental CollegeNiigata U.Osaka U.Osaka City U.Panjab U.Peking U.U. of PittsburghPrinceton U.RikenSaga U.USTC

Seoul National U.Shinshu U.Sungkyunkwan U.U. of SydneyTata InstituteToho U.Tohoku U.Tohuku Gakuin U.U. of TokyoTokyo Inst. of Tech.Tokyo Metropolitan U.Tokyo U. of Agri. and Tech.Toyama Nat’l CollegeU. of TsukubaUtkal U.VPIYonsei U.

8

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 vertex Muon / KL identification

, 0 reconstructione+-, KL identification

8.0 GeV e-

9

B0 J/ KL

J/

Event Display of BEvent Display of B00 J/ J/ K KLL

10

BB00 J/ J/ K K00 : 532 M BB pairs : 532 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

__

11

= 0.425 (Belle) 0.56 (BaBar)

Principle of TCPV measurementPrinciple of TCPV measurement

t z c

CP-side

Flavor tag and vertex reconstr

uction

1. Fully reconstruct one B-meson which decays to CP eigenstate2. Tag-side determines its flavor3. Proper time (t) is measured from decay-vertex difference (z)

electron(8GeV)

positron(3.5GeV)

(4S)resonance B1

B2

+-K+

-0

D

+

-

KS/L

J/

z ~ 200m(Belle)

B0

B0_

12

)cossin(141,1 tmAtmSetqP

t

)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_B

0 tag

-CPsin21

Mixing of D*lGood tag region(O

F-SF

)/(O

F+SF

)

t| (ps)

13

B0 J/ KS B0 J/ KL

Asym. = -CPsin21sinmt

CP odd :CP=-1 CP even :CP=+1

B0 tag_B

0 tagB0 tag_B

0 tag

0 0

SigSig+BG

Belle preliminary

14

B0 J/ KS B0 J/ KL

CP odd :CP=-1 CP even :CP=+1

B0 tag_B

0 tagB0 tag_B

0 tag

0 0

SigSig+BG

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

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

stat error stat error

Belle preliminary

15

B0 J/ KS B0 J/ KL

Asym. = -CPsin21sinmt

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

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

CP odd :CP=-1 CP even :CP=+1

B0 tag_B0 tag

B0 tag_B

0 tag

0 0

stat error stat error

16

B0 J/ KS

B0 tag_B0 tag

0 B0 J/ KL

B0 tag_B

0 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

17

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

(386 M BB pairs)

B0 tag_B

0 tag

532 M BB pairs_ _

Belle preliminary

18

Constraint on the Unitarity TriangleConstraint on the Unitarity Triangle

1=20o

1=70o

??

Intrinsic ambiguity still remains …21 -21

19

BB00 D[K D[KSS++--]h]h00 (h (h00==00,,,,))__

M2(KS)

M2(KS)

f-+

M2(KS)

M2(KS)f+-

hep-ex/0605023submitted to PRL

Time-dependence of Dalitz gives sin21 and cos21

sin21 = 0.78 ±0.44(stat) ±0.22(syst)

cos21 = 1.87 (stat) (syst)+0.40 +0.220.53 0.32

Negative cos21 isdisfavored

at 98.3% C.L.

20

Constraint on the Unitarity TriangleConstraint on the Unitarity Triangle

1=20o

1=70o

??

(^_^)

1 = 20.0o ± 1.3o

(Belle data only)

Time-dependent Dalitz analysisof B0 D[ KS ]h0

hep-ex/0605023 submitted to PRL

Disfavored at98.3% C.L.

_

21

KEKB Integrated luminosityas a function of time

1 /ab1~1o

B0 J/ KS0

B0 J/ KL0

Based on 532 M BBsin21= 0.642 ±0.031 (stat) ±0.017 (syst) A = 0.018 ±0.021 (stat) ±0.014 (syst) 1 = 20.0o ± 1.3o

_

Summary

22

Excellent combined results will be shownby next speaker, K. George

The 1 is one of the most precise SM parameter

The sin21 is good SM anchor point for new physics hunting Tree Penguin

KEKB + PEP-IIExceeds 1 /ab !

KEKB

PEP-II

23

backup

24

History of sin21 at Belle• 6.2 /fb : 0.45±0.45

0.22±0.60 (J/KS) , -1±0.89 (J/KL)• 29.1 /fb : 0.99±0.14

0.81±0.20 (J/KS) , 1.31±0.23 (J/KL)• 78/fb : 0.72±0.07 (combined w/ (2S)Ks etc.)

0.73±0.10 (J/KS) , 0.78±0.17 (J/KL)• 140 /fb : 0.73±0.05 (combined w/ (2S)Ks etc.)

0.67±0.08 (J/KS) , 0.77±0.13 (J/KL)• 357 /fb : 0.65±0.04 (J/K0 combined)

0.67±0.05 (J/KS) , 0.62±0.07 (J/KL)• 492 /fb : 0.64±0.03

0.64±0.04 (J/KS) , 0.64±0.06 (J/KL)

Stat. error only

25

Systematic errors of B0J/K0

Sin21 AVertexing 0.012 0.009Flavor tagging 0.004 0.003t Resolution 0.006 0.001Physics parameters. 0.001 0.001Possible fit bias 0.007 0.004BG fractions (J/KS) 0.003 0.001BG fractions (J/KL) 0.005 0.002BG t 0.001 0.001Tag-Side interference 0.001 0.009

total 0.017 0.014

26

Misalignment

• Misalign DSSDs in MC to reproduce IP resolution (15um shift, 0.15mrad)

27

Tag Side Interference

• Interference between CKM-favored and CKM-suppressed BD transitions in the tag-side.

• Estimated by pseudo-experiments whose parameters are obtained from B0D*lnu samples

• No interference for semi-leptonic decay in tag side (It was included till last year)

28

Flavor TagNIM A 533, 516 (2004)

29

Wrong tag probabilityr = 1-2w

tmPPPPA dSFOF

SFOFchg

cos

tmwA davgmeaschg cos)21(

Estimate w from time-dependentB0-B0 mixing