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New CP Violation Results from B-meson Decays at Belle December 1, 2004 Yee Bob Hsiung National Taiwan University @ 清清清清 Physics Colloquium

New CP Violation Results from B-meson Decays at Belle

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New CP Violation Results from B-meson Decays at Belle. Yee Bob Hsiung National Taiwan University. December 1, 2004. 清華大學 Physics Colloquium. @. What is CP Violation?. CP Violation or Matter-Antimatter asymmetry C: charge conjugation P: space inversion T: Time reversal. - PowerPoint PPT Presentation

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Page 1: New CP Violation Results from  B-meson Decays at  Belle

New CP Violation Results from B-meson Decays at Belle

December 1, 2004

Yee Bob HsiungNational Taiwan

University

@清華大學 Physics Colloquium

Page 2: New CP Violation Results from  B-meson Decays at  Belle

2

What is CP Violation?

CP ViolationorMatter-Antimatterasymmetry

C: charge conjugationP: space inversionT: Time reversal

Page 3: New CP Violation Results from  B-meson Decays at  Belle

3

Why Studying CP Violation?

Page 4: New CP Violation Results from  B-meson Decays at  Belle

4

CP Violation in the Standard Model

CP violation () was first discovered in Kaon decays (1964)

33 years later (1997) “direct” CP violation was observed in K to 2decays (’)

CP violation in the B decays can now be studied in both Belle(KEK) and BaBar(SLAC) in detail

Page 5: New CP Violation Results from  B-meson Decays at  Belle

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Cabbibo-Kobayashi-Maskawa Matrix

Page 6: New CP Violation Results from  B-meson Decays at  Belle

6

CP-Violation in Standard Model

'

'

'

ub

cb

td

ud us

cd cs

ts tb

V

V

V V

d d

s s

b b

V

V

V

V V

, , , ,

* *ij ik ji ki jki u c t i u c t

V V V V

JCP=2(Triangle Area) Is the unique measure of CP-Violation in SM

Ng=3 Nphase=1 CP-Violation Possible

A phase in the quark-quark current leads to CP-Violation (Kobayashi, Maskawa, 1973)

6 unitarity relations( triangles in the complex plane)

* * *Im( ) Im( ) ~ sin cos Im( ) CP ud us ts td u t c c tJ V V V V

Page 7: New CP Violation Results from  B-meson Decays at  Belle

7

Wolfenstein Parametrization

Page 8: New CP Violation Results from  B-meson Decays at  Belle

8

CP Violating Phase

Page 9: New CP Violation Results from  B-meson Decays at  Belle

9

The Kaon System

Page 10: New CP Violation Results from  B-meson Decays at  Belle

10

NA48 @ CERN Fermilab

Page 11: New CP Violation Results from  B-meson Decays at  Belle

11

Penguin Diagram

S = 1

Direct CP Violation

Page 12: New CP Violation Results from  B-meson Decays at  Belle

12

Direct CP Violation: Re(’/)

Page 13: New CP Violation Results from  B-meson Decays at  Belle

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Kaon Decays and the SM

JCP=2(Triangle Area) is the unique measure of CP-Violation in SM

JCP = Im(Vud*VusVts

*Vtd) ~ cosc sinc Imt

In the Wolfenstein parameterisation (, A, , ): Im t = A2 5 , Re t = A2 5

CP

-Vio

lati

on

KL to 2 ’/

Page 14: New CP Violation Results from  B-meson Decays at  Belle

14

The Unitarity Triangle

Page 15: New CP Violation Results from  B-meson Decays at  Belle

15

The Unitarity Triangle

Page 16: New CP Violation Results from  B-meson Decays at  Belle

16

Page 17: New CP Violation Results from  B-meson Decays at  Belle

17

The B Factories: KEKB and SLAC-PEPII

Page 18: New CP Violation Results from  B-meson Decays at  Belle

18

感謝國科會九年來的支持!

Page 19: New CP Violation Results from  B-meson Decays at  Belle

19

KEK (日本高能實驗室 ) 鳥瞰圖

筑波山

Page 20: New CP Violation Results from  B-meson Decays at  Belle

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KEKB 加速器示意圖8 GeV electron 3.5 GeV positron

KEKB Collider

BBS )4( 電子 正電子

@ 1.2A x 1.6A@ 1.2A x 1.6ALLpeakpeak = 1.39 x 10 = 1.39 x 1034 34 secsec-1-1cmcm-2 -2

275M BB

253 fb-1 on Y(4S) 28 fb-1 below Y(4S)

Page 21: New CP Violation Results from  B-meson Decays at  Belle

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The Billion $ Question: 測量 B系統之 CP破壞

One B Decay CP EigenstateOther B Decay Tag FlavorMeasure Both Decay Vertex

Belle

J/KS, ’ KSKS

Red Hot !

台大都掌握中

2001

B 約兆分之一秒左右衰變

Page 22: New CP Violation Results from  B-meson Decays at  Belle

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Belle DetectorBelle Detector

/ KL detection 14/15 lyr. RPC+Fe

Central Drift Chamber small cell +He/C2H5

CsI(Tl) 16X0

Aerogel Cherenkov cnt. n=1.015~1.030

Si vtx. det. 3(4) lyr. DSSD

TOF conter

SC solenoid 1.5T

8 GeV e

3.5 GeV e

Page 23: New CP Violation Results from  B-meson Decays at  Belle

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B-meson ReconstructionB-meson Reconstruction

Energy difference:

Beam-constrained mass:

Utilize special Kinematicsat Y(4S)

222 )()( iCMbc pEM

2CMi EEE

(ES)

Page 24: New CP Violation Results from  B-meson Decays at  Belle

24

Continuum SuppressionContinuum Suppression

e+

e-

e+

e-

qq

Signal B

Other B

Dominant Background for rare decays:

Continuum

Jet-like

BB

spherical

e+e qq “continuum” (~3x BB)

To suppress: use event shape variables

continuum

Y (4S)

Page 25: New CP Violation Results from  B-meson Decays at  Belle

25

SVD UpgradeSVD Upgrade

SVD1 SVD2

• 1 MRad >20 MRad• 3 layers 4 layers • 23º<<139º 17º<<150º• Rbp = 2.0 cm 1.5 cm

Better I.P. resolutions

2003 summer

Impact parameter resolution

r Z

152M BB pairs with SVD1+ 123M BB pairs with SVD2

__

Page 26: New CP Violation Results from  B-meson Decays at  Belle

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Belle SVD2 Upgrade

Collaborate w/Tokyo & Princeton

etc.

SVD2 under constructionInstall Summer 2003

NTU Contribution: TTMTTMTrigger Timing ModuleTrigger Timing Module

From 3-layers of SVD1 to 4-layers 4-layers + self-tracking self-tracking

FPGAsFPGAs

Page 27: New CP Violation Results from  B-meson Decays at  Belle

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Students!Students!

Page 28: New CP Violation Results from  B-meson Decays at  Belle

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SVD2: lifetime & mdSVD2: lifetime & md

0B

B

dm

0B

B

dm

[ps]

[ps]

[ps1]

1.534 0.008 0.010

1.635 0.011 0.011

0.511 0.005 0.006

1.518 0.012

1.652 0.014

0.516 0.007

SVD1 _(152M BB)

SVD2 _(123M BB)

New detector resolution is well understood

SVD2 only

Belle preliminary

D0+, J/ K , D–+, D*–+/+, D*l

(stat)

(stat)

(stat)[Belle-conf-0436]

Page 29: New CP Violation Results from  B-meson Decays at  Belle

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B B

Penguin d

b

d

s/d

u

u

W

B0d -

+

Vus/d

Vub

Tree

• Simplest charmless rare decay modes• Tree - Penguin interference Direct CP Violation

Key prediction of Kobayashi-Maskawa model

Key prediction of Kobayashi-Maskawa model

Understanding of Penguin

_ _ (B f ) (B f ) _ _ (B f ) (B f )

ACP =

Anomaly (New Physics)

B0d

d

b

du

u

W

g +

-

Vts/dVtb

ts/d

Page 30: New CP Violation Results from  B-meson Decays at  Belle

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ACP(B0 K)ACP(B0 K)

2nd Evidence for DCPV at Belle ! [A() 3.2]

ACP = -0.101 0.025 0.005 [PID efficiency bias correction: A = -0.01 0.004]

275M BB New

3.9 significance[submitted to PRL]

B0 K _B0 K

Signal: 2139 53

Page 31: New CP Violation Results from  B-meson Decays at  Belle

31

B0 + CPV ResultB0 + CPV Result

A = +0.58 0.15(stat) 0.07(syst)S = 1.00 0.21(stat) 0.07(syst)

S

A

t (ps)

Direct CPV3.2

[PRL93,021801 (2004)]

good tag

152M BB

Page 32: New CP Violation Results from  B-meson Decays at  Belle

32

ACP(B K)ACP(B K)

ACP(K) = 0.04 0.05 0.02

275M BB New

K: 728 53

hint that ACP(K) ACP(K) ? (2.4)

Large EW penguin (Z0) ?

New Physics ?

_d

d

K

u u

B sb

Page 33: New CP Violation Results from  B-meson Decays at  Belle

33

Observation of B0 00

Observation of B0 00

275M BB, New

Evidence (LP03) Observation !

B = (2.32 ) x 10-6 Large Br established

Signal: 82 16 (6.0)

ACP = 0.44 0.51

uses same Flavor-tagging as TCPV analysis

1st measurement !

Mbc[Belle-conf-0406]

Key mode for 2() in B CPV isospin analysis

0.440.48

0.220.18

0.170.16

Page 34: New CP Violation Results from  B-meson Decays at  Belle

34

Radiative & EW PenguinsRadiative & EW Penguins

EW

~1/100

Loops Sensitive to New Physics

K* TCPV

Br, ACP ~SM

b s penguin

b sl+l penguin

b d penguin

l+

l

Page 35: New CP Violation Results from  B-meson Decays at  Belle

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B K(*) l+lB K(*) l+l

79 10signals

82 11signals

[Belle-conf-0415]

B (Kll)= (5.50 0.27 0.02)

275M BB

0.750.70

B (K*ll)= (16.5 0.9 0.4 )2.32.2

>10 signalsupdate

LP03: B Xsll, K(*)ll : Belle/BaBar Br, ACP ~SM

x 10-7

q2 (GeV2/c2)

Mbc

Page 36: New CP Violation Results from  B-meson Decays at  Belle

36

Time-dependent CP ViolationTime-dependent CP Violation

B0

B0mixing

=B0

B0

+

+ New Physics with New Phase

Sbs sin21 , A can 0Sbs =sin21, A=0

SM: b s Penguin phase = J/KS

(b c)

tstb VV

Mixing induced CPV Direct CPV

ACP (t) = S sin(mt) + A cos (mt)

(TCPV)fCPfCP

Page 37: New CP Violation Results from  B-meson Decays at  Belle

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Time Dependent CP Asymmetry

0 0

0 0

0 0

( ) ( )( ) sin cos

( ) ( )

d CP d CPB B

d CP d CP

B f B fA t m At m

B f fS t

B

2

2 2

: eigenvalue

2 Im( ) | | 1,

| | 1 | | 1

f

AS

CP

S = f sin21: SM prediction

A = 0 or || = 1 No direct CPV

Inputs: f = 1, S = 0.6A = 0.0

0d CPB f0

d CPB f

fq

p

Af

Af

CP

CP

CP

Page 38: New CP Violation Results from  B-meson Decays at  Belle

38

b sqq Penguin CPVb sqq Penguin CPV

Belle @LP03 (140 fb-1)

“sin21”= 0.96 0.51

B0 Ks

sin21=0.728 0.06

B0 J/Ks etc

3.5 deviation from the SM !

--

[PRL 91, 261602 (2003)]

Page 39: New CP Violation Results from  B-meson Decays at  Belle

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B0 K0B0 K0

Similar to J/KL recon.+ sophisticated continuum suppression

includes Ks (Nsig=13 5)

KS

Nsig=139 14purity 0.63

pB*

Nsig= 36 15

KL

purity 0.17

275M BB

Page 40: New CP Violation Results from  B-meson Decays at  Belle

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B0 KS : Mass & Helicity B0 KS : Mass & Helicity

Helicity

bkg

Mass

Page 41: New CP Violation Results from  B-meson Decays at  Belle

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B0 K0 : CPV ResultB0 K0 : CPV Result

K0

KS + KL

: S (K0) = +0.06 0.33 0.09

A (K0) = +0.08 0.22 0.09 ~2 away from SM

KS + KL

: S (K0) = +0.06 0.33 0.09

A (K0) = +0.08 0.22 0.09 ~2 away from SM

Good tags

Poor tags

S = 0.73fit Good tags

275M BB

Page 42: New CP Violation Results from  B-meson Decays at  Belle

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Checks: sin21 (B0 J/ KS/L)Checks: sin21 (B0 J/ KS/L)

SVD1: 152M BB

t (ps)

Good tags

SVD1

Validation of new data sample (SVD2)

SVD2: 123M BB

Good tags

SVD2

_

S = 0.696 0.061 (stat)

A = 0.011 0.043 (stat)

S = 0.696 0.061 (stat)

A = 0.011 0.043 (stat)

S = 0.629 0.069 (stat)

A = 0.035 0.044 (stat)

S = 0.629 0.069 (stat)

A = 0.035 0.044 (stat)

_

SVD2: S = +0.78 0.45 A =+0.17 0.33

SVD1:S = 0.68 0.46A = 0.02 0.28

many systematic checks, all ok

~2.3K0

Page 43: New CP Violation Results from  B-meson Decays at  Belle

43

History of “sin21” with K0

106

Belle

BABAR

_sin21 from ccs“s

in2

1”

Page 44: New CP Violation Results from  B-meson Decays at  Belle

44

B0’KS KKKSB0’KS KKKS

’KS KKKS

Nsig=512 27purity 0.61

Nsig=399 28purity 0.56

S = +0.65 0.18 0.04 S = +0.49 0.18 0.04 ( ) A = 0.19 0.11 0.05 A = 0.08 0.12 0.07

CP=+1: 1.03 0.15 0.05

“sin21”

Raw

Asy

mm

etry

Good tags Good tags

S = 0.73fit

0.170.0

Raw

Asy

mm

etry

(~0.5@SM) (~1.0@SM)

high statistics modes(excluded)

( , )

275M BB

Page 45: New CP Violation Results from  B-meson Decays at  Belle

45

B0KS f0(980)KS

B0KS f0(980)KSKS additional modes

Nsig=31 7

purity 0.56

Nsig=94 14purity 0.53

f0(980)KS

S = +0.75 0.64 S = 0.47 0.41 0.08 A = 0.26 0.48 0.15 A = 0.39 0.27 0.08

“sin21”

Raw

Asy

mm

etry

Good tags

S = 0.73fit

0.130.16

Good tagsRaw

Asy

mm

etry

(~2.9@SM)(~0@SM)

275M BB

Page 46: New CP Violation Results from  B-meson Decays at  Belle

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Summary of b sqq CPVSummary of b sqq CPV--

2.4

“sin21” 275M BB

(A: consistent with 0)

Page 47: New CP Violation Results from  B-meson Decays at  Belle

47

Charmless B Br SummaryCharmless B Br Summary

HFAG P.Chang (NTU) J.Alexander (Cornell) J.Smith (Colorado)

Complete list (other Br & ACP )http://www.slac.stanford.edu/xorg/hfag/rare/ x10-6

Page 48: New CP Violation Results from  B-meson Decays at  Belle

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Summary CP Violation has been well established in the kaon s

ystem, both “direct” and “indirect” and now being extensively explored in B-meson system

Evidence of “direct” CP violation has been seen inB K+ (~-10%), search for new physics beyond the Standard Model will continue in bs penguin modes and 3 angles measurement of unitarity triangle.

However, the origin of CP violation may well be uncovered from both K and B system in the next 5-10 years by comparing the (in)consistency of the unitarity triangles

There maybe hints of new physics beyond the SM in the K and B system which will call for high luminosity (1036 SuperB) machine, better experiments at JHF-JPARC and new physics studies/searches in the LHC and/or LC era

Page 49: New CP Violation Results from  B-meson Decays at  Belle

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Future Prospect of Measurements

Page 50: New CP Violation Results from  B-meson Decays at  Belle

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Future Prospect of Measurements

ab-1

ab-1

ab-1

Going forSuper B factory

Page 51: New CP Violation Results from  B-meson Decays at  Belle

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The End