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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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New CP Violation Results from B-meson Decays at Belle
December 1, 2004
Yee Bob HsiungNational Taiwan
University
@清華大學 Physics Colloquium
2
What is CP Violation?
CP ViolationorMatter-Antimatterasymmetry
C: charge conjugationP: space inversionT: Time reversal
3
Why Studying CP Violation?
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
5
Cabbibo-Kobayashi-Maskawa Matrix
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
7
Wolfenstein Parametrization
8
CP Violating Phase
9
The Kaon System
10
NA48 @ CERN Fermilab
11
Penguin Diagram
S = 1
Direct CP Violation
12
Direct CP Violation: Re(’/)
13
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 ’/
14
The Unitarity Triangle
15
The Unitarity Triangle
16
17
The B Factories: KEKB and SLAC-PEPII
18
感謝國科會九年來的支持!
19
KEK (日本高能實驗室 ) 鳥瞰圖
筑波山
20
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)
21
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
22
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
23
B-meson ReconstructionB-meson Reconstruction
Energy difference:
Beam-constrained mass:
Utilize special Kinematicsat Y(4S)
222 )()( iCMbc pEM
2CMi EEE
(ES)
24
Continuum SuppressionContinuum Suppression
e+
e-
e+
e-
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)
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
__
26
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
27
Students!Students!
28
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]
29
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
30
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
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
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
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
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
35
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
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
37
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
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)]
39
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
40
B0 KS : Mass & Helicity B0 KS : Mass & Helicity
Helicity
bkg
Mass
41
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
42
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
43
History of “sin21” with K0
106
Belle
BABAR
_sin21 from ccs“s
in2
1”
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
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
46
Summary of b sqq CPVSummary of b sqq CPV--
2.4
“sin21” 275M BB
(A: consistent with 0)
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
48
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
49
Future Prospect of Measurements
50
Future Prospect of Measurements
ab-1
ab-1
ab-1
Going forSuper B factory
51
The End