Title: f1 from b?c decays at Belle
1f1 from b?c decaysat Belle
- O. Tajima (KEK)
- Belle collaboration
- EPS conf. July 21, 2005
2Outline
- Introduction
- sin2f1 from B0 ? J/y K0
- f1 from B0 ? DKSpp- h0
- Summary
Update
_
New !
f1 ? b A ? -C
3Kobayashi-Maskawa Phase
l 0.22
CP violation is due to a complex phase in quark
mixing matrix
CP violation parameters (f1, f2, f3) (b, a, g )
4sin2f1 measurement
Vtd
Vtd
A0
xCP CP eigenvalue, 1 (-1) for CP even (odd)
We can measure CPV (asym.) as a function of
proper time diff.
5Principle of TCPV measurement
CP-side
m
J/y
m-
?(4S) resonance
B1
electron (8GeV)
KS/L
positron (3.5GeV)
B2
bg 0.425 (Belle) 0.56 (BaBar)
- Fully reconstruct one B-meson which decays to CP
eigenstate
6Principle of TCPV measurement
CP-side
m
J/y
m-
?(4S) resonance
B1
electron (8GeV)
KS/L
B0
positron (3.5GeV)
nm
B2
p-
bg 0.425 (Belle) 0.56 (BaBar)
K
p-
Flavor tag and vertex reconstruction
Dz 200mm (Belle)
m
- Fully reconstruct one B-meson which decays to CP
eigenstate - Tag-side determines its flavor
- Proper time (Dt) is measured from decay-vertex
difference (Dz)
7KEKB the highest luminosity in the world
Located in Tsukuba, Japan
Belle detector
3.5 GeV e ? 8.0 GeV e- ee- ? ?(4S) with bg
0.425 22 mrad crossing angle
- Lpeak (1.58?1034)/cm2/sec
- ? gt 1M BB pairs/day
- integrated L 467 /fb
_
_
386 M BB pairs analysis are shown, today
8International Collaboration Belle
Seoul National U. Shinshu U. Sungkyunkwan U. U.
of Sydney Tata Institute Toho U. Tohoku U. Tohuku
Gakuin U. U. of Tokyo Tokyo Inst. of Tech. Tokyo
Metropolitan U. Tokyo U. of Agri. and
Tech. Toyama Natl College U. of Tsukuba Utkal
U. VPI Yonsei U.
Nagoya U. Nara Womens U. National Central
U. Natl Kaoshiung Normal U. National Taiwan
U. National United U. Nihon Dental
College Niigata U. Osaka U. Osaka City U. Panjab
U. Peking U. U. of Pittsburgh Princeton
U. Riken Saga U. USTC
IHEP, Vienna ITEP Kanagawa U. KEK Korea U. Krakow
Inst. of Nucl. Phys. Kyoto U. Kyungpook Natl U.
EPF Lausanne Jozef Stefan Inst. / U. of
Ljubljana / U. of Maribor U. of Melbourne
Aomori U. BINP Chiba U. Chonnam Natl U. U. of
Cincinnati Ewha Womans U. Frankfurt U. Gyeongsang
Natl U. U. of Hawaii Hiroshima Tech. IHEP,
Beijing IHEP, Moscow
9Belle Detector
K/p separation
- , p0 reconstruction
- e-, KL identification
Aerogel Cherenkov Counter n 1.0151.030
Electromagnetic Calorimeter CsI(Tl) 16X0
3.5 GeV e
TOF counter
K/p separation
charged particle tracking
8.0 GeV e-
Central Drift Chamber momentum, dE/dx
50-layers He/C2H6
B vertex
Muon / KL identification
Si Vertex Detector 4-layer DSSD
KL m detector 14/15 layer RPCFe
10B0 ? J/y K0 386 M BB pairs
_
B0 ? J/y KS
B0 ? J/y KL
0
0
Nsig 5264 Purity 98 CP odd
Nsig 4792 Purity 60 CP even
pKL information is poor ? lower purity
Belle preliminary
11Principle of TCPV measurement
CP-side
m
J/y
m-
?(4S) resonance
B1
electron (8GeV)
KS/L
B0
positron (3.5GeV)
nm
B2
p-
bg 0.425 (Belle) 0.56 (BaBar)
K
p-
Flavor tag and vertex reconstruction
Dz 200mm (Belle)
m
- Fully reconstruct one B-meson which decays to CP
eigenstate - Tag-side determines its flavor
- Proper time (Dt) is measured from decay-vertex
difference (Dz)
12 -xCPsin2f1
B0 tag
S 0.65 A 0.00
R detector resolution w wrong tag fraction
(misidentification of flavor) ? (1-2w)
quality of flavor tagging They are well
determined by using control sample Dln,
D()p etc
13B0?J/y KS , KL
Belle preliminary
B0 ? J/y KS
B0 ? J/y KL
0
0
B0 tag
B0 tag
CP odd xCP-1
CP even xCP1
Asym. -xCPsin2f1sinDmDt
sin2f1 0.668 0.047 A - 0.021 0.034
sin2f1 0.619 0.069 A 0.049 0.039
14B0 ? J/y K0 combined result
sin2f1 0.652 0.039 (stat) 0.020 (syst) A
0.010 0.026 (stat) 0.036 (syst)
_
386 M BB pairs
B0 tag
Belle preliminary
BG subtracted distributions (good tag region)
previous measurement sin2f1 0.728 ? 0.061 (152 M
BB pairs)
_
consistent 1.2s
Asymsin2f1sinDm(-xCPDt)
15Constraint on the Unitarity Triangle
?
f170o
sin2f1
?
f120o
Intrinsic ambiguity still remains 2f1 ? p-2f1
f1
16B0 ? DKSpp-h0Direct measurement of f1
_
hh0 CP eigenvalue, l orbital angler momentum
17B0 ? DKSpp-h0Direct measurement of f1
_
We can measure f1 with Time-dependent Dalitz
fitting hep-ph/0503174, A.Bondar, et al.
q/p1, arg(q/p)2f1
D0 ? KSpp-
18Dalitz PDF is calibrated with real data
_
D ? D0(KSpp-) pslow in real data Charge of
slow p distinguish D0 or D0
_
Modeled with 18 resonances one
non-resonant amplitude
Phys. Rev. D 70, 02003 (2004) f3 measurement with
Dalitz
will be talked by T. Gershon Fri 22, 900
19Reconstruction of B0 ? DKSpp-h0
_
D0 p0
D0 w
D0 h
D0 p0, h
Nsig 157 24 purity 59
Nsig 67 10 purity 86
Nsig 58 13 purity 60
Nsig 27 11 purity 52 D0 ? D0 p0
D ? D0 pi0 Dpi0 22 - 9 Deta 5- 6
TOTAL Nsig 309 31 purity 63
Belle preliminary
20Dalitz plot for the signal candidates
D0 f-
M(KSp-)
_
D0 f-
M(KSp)
21Background of B0 ? DKSpp-h0
_
fraction Dalitz PDF (f-/-)
signal 63 Calibrated by real data D ? D0(KSpp-) pslow Phys. Rev. D 70, 02003 (2004) for f3 will be talked by T.Gershon (Fri 22, 900)
B ? D X 13 Calibrated by real data D ? D0(KSpp-) pslow Phys. Rev. D 70, 02003 (2004) for f3 will be talked by T.Gershon (Fri 22, 900)
qq ? D X 6 Calibrated by real data D ? D0(KSpp-) pslow Phys. Rev. D 70, 02003 (2004) for f3 will be talked by T.Gershon (Fri 22, 900)
B ? none-D 5 Mbc-DE sideband
qq ? none-D 13 Mbc-DE sideband
_
_
Consistent with World Average
22Time-Dependent Dalitz fit results
Belle preliminary
Final state f1 (o)
D0 p0 11 26
D0 w, h 28 32
D0 p0, h 25 35
combined 16 21(stat) 11(syst)
-30o lt f1 lt 62o (95 C.L.)
23Impact for f1 T-Dep. Dalitz analysis
Consistent with B0?J/yK results cos2f1 0.87
0.75, hep-ex/0504046
?
f170o
Disfavored gt2s
sin2f1
?
(_)
f120o
Intrinsic ambiguity almost solved !! 2f1 ? p-2f1
f1
24Consistency of TCPV results with indirect
constraints
f1 (20.3 1.8)o (Belle only)
25Summary
_
- Belle results with 386 M BB pairs
- B0 ? J/y K0 Time-dependent analysis
- sin2f1 0.6520.039(stat)0.020(syst)
- Ambiguity 2f1 ? p-2f1 is solved by
- B0 ? DKSpp- h0 Time-dep. Dalitz analysis
- f1 16 21(stat)11(syst) (o)
- The f1 value is the most precise UT parameter
- f1 (20.3 1.8)o (Belle only)
hep-ex/0507037
_
hep-ex/0507065
All new results are preliminary
26backup
27Observables for TCPV
CP Violation manifests itself in proper-time
difference (Dt) distributions of two B meson
decays.
ACP
S sin(DmDt) A cos (DmDt)
Direct CPV
Mixing induced CPV
(BaBar A -C)
28History of Asymmetric B Factories
KEKB
PEP-II
29Event DisplayB0 ? J/Y KS J/Y?mm-
KS?pp-
3.5 GeV e
8.0 GeV e-
30Belle Babar
31Systematic Errors for J/PsiK0
DS DA
Vertexing 0.015 0.030
Flavor Tag 0.006 0.007
Dt Resolution 0.005 0.001
Possible fit bias 0.007 0.005
Physics parameters 0.001 0.001
BG Dt shape 0.006 0.005
BG fraction (J/yKS) 0.002 0.003
BG fraction (J/yKL) 0.005 0.002
Tag side interference 0.003 0.017
Total 0.020 0.036
Belle preliminary
32History of sin2f1 fromB0 ? J/PsiK0
- 152 M B meson pairs
- sin2f1 0.693 0.065 (stat)
- 386 M B meson pairs
- sin2f1 0.652 0.039 (stat) 0.020 (syst)
-
consistent 0.6s
33History of sin2f1 fromB0 ? J/PsiKs
- 152 M B meson pairs
- sin2f1 0.67 0.08 (stat)
- 386 M B meson pairs
- sin2f1 0.67 0.05 (stat)
-
well consistent
34History of sin2f1 fromB0 ? J/PsiKL
- 152 M B meson pairs
- sin2f1 0.77 0.13 (stat)
- 386 M B meson pairs
- sin2f1 0.62 0.07 (stat)
-
consistent 1.2s
35Time-Dependent Dalitz fit results
Belle preliminary
Asym.(Dt) -sin2f1sinDmDt
Final state f1 (o)
D0 p0 11 26
D0 w, h 28 32
D0 p0, h 25 35
combined 16 21(stat) 11(syst)
In case of D0 ? KS r(pp-) 0.62 lt Mpp lt 0.92
GeV/c2
-30o lt f1 lt 62o (95 C.L.)
36Systematic Errors for B0 ? DKSpp-h0
_
Belle preliminary
f1 (o)
Vertexing, Flavor tag and Dt resolution 1
D ? KSpp- Dalitz PDF 5
Background PDF (Dalitz Dt) 10
Suppressed b ? ucbard 1
Total 11
? Mainly Dalitz
f1 16 21(stat)11(syst) (o)
37Final state hh0 l orbital anguler momentum
D0 p0 - 0
D0 w 1
D0 h - 0
D0 p0, h - 1
38Stat. Error of Time-Dep Dalitz Fit
fitting result
fitting error
39PDF of Time-Dependent Dalitz
40Flavor Tag
NIM A 533, 516 (2004)
41Wrong tag probability
NIM A 533, 370 (2004) for resolution
Estimate w from time-dependent B0-B0 mixing
42Wrong tag probability cont.
r fraction wave eeff
0.000 -0.250 0.384 0.467 0.002
0.250 -0.500 0.165 0.324 0.021
0.500 -0.625 0.105 0.223 0.032
0.625 -0.750 0.112 0.160 0.052
0.750 -0.875 0.089 0.101 0.057
0.875 -1.000 0.144 0.020 0.133
Total eeff 0.296 0.010