f1 from b?c decays at Belle - PowerPoint PPT Presentation

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f1 from b?c decays at Belle

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TOF counter. 3.5 GeV e Central Drift Chamber. momentum, dE/dx. 50-layers He/C2H6 ... sin2f1= 0.652 0.039 (stat) 0.020 (syst) A = 0.010 0.026 (stat) 0.036 (syst) ... – PowerPoint PPT presentation

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Title: f1 from b?c decays at Belle


1
f1 from b?c decaysat Belle
  • O. Tajima (KEK)
  • Belle collaboration
  • EPS conf. July 21, 2005

2
Outline
  • Introduction
  • sin2f1 from B0 ? J/y K0
  • f1 from B0 ? DKSpp- h0
  • Summary

Update
_
New !
f1 ? b A ? -C
3
Kobayashi-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 )
4
sin2f1 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.
5
Principle 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

6
Principle 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
  1. Fully reconstruct one B-meson which decays to CP
    eigenstate
  2. Tag-side determines its flavor
  3. Proper time (Dt) is measured from decay-vertex
    difference (Dz)

7
KEKB 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
8
International 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
9
Belle 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
10
B0 ? 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
11
Principle 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
  1. Fully reconstruct one B-meson which decays to CP
    eigenstate
  2. Tag-side determines its flavor
  3. 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
13
B0?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
14
B0 ? 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)
15
Constraint on the Unitarity Triangle
?
f170o
sin2f1
?
f120o
Intrinsic ambiguity still remains 2f1 ? p-2f1
f1
16
B0 ? DKSpp-h0Direct measurement of f1
_
hh0 CP eigenvalue, l orbital angler momentum
17
B0 ? 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-
18
Dalitz 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
19
Reconstruction 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
20
Dalitz plot for the signal candidates
D0 f-
M(KSp-)
_
D0 f-
M(KSp)
21
Background 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
22
Time-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.)
23
Impact 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
24
Consistency of TCPV results with indirect
constraints
f1 (20.3 1.8)o (Belle only)
25
Summary
_
  • 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
26
backup
27
Observables 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)
28
History of Asymmetric B Factories
KEKB
PEP-II
29
Event DisplayB0 ? J/Y KS J/Y?mm-
KS?pp-
3.5 GeV e
8.0 GeV e-
30
Belle Babar
31
Systematic 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
32
History 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
33
History 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
34
History 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
35
Time-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.)
36
Systematic 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)
37
Final state hh0 l orbital anguler momentum
D0 p0 - 0
D0 w 1
D0 h - 0
D0 p0, h - 1
38
Stat. Error of Time-Dep Dalitz Fit
fitting result
fitting error
39
PDF of Time-Dependent Dalitz
40
Flavor Tag
NIM A 533, 516 (2004)
41
Wrong tag probability
NIM A 533, 370 (2004) for resolution
Estimate w from time-dependent B0-B0 mixing
42
Wrong 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
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