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3 _ d b _ c c s d _ w B0B0 J/ K0K0 sin2 1 measurement V* td __ t d t b b d _ w w B0B0 B0B0 _ B0B0 B0B0 qpqp f CP = A CP ( t ; B 0 J/ K 0 ) ( t ; B 0 J/ K 0 ) ( t ; B 0 J/ K 0 ) ( t ; B 0 J/ K 0 ) _ _ = - cp sin2 1 sin( m t) + A cos ( m t) Mixing induced CPV Direct CPV (A = C) CP : CP eigenvalue, +1 (-1) for CP even (odd) A=0
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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