CP Violation and Rare B Decays at Belle DESY Seminar 11 ... · DESY Seminar 11 Sep, 2001. CP...
Transcript of CP Violation and Rare B Decays at Belle DESY Seminar 11 ... · DESY Seminar 11 Sep, 2001. CP...
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
Representing the Belle Collaboration
CP Violationand
Rare B Decaysat Belle
M. Hazumi (Osaka University, Osaka, Japan)
DESY Seminar11 Sep, 2001
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
Outline
• Introduction
• KEKB Accelerator and Belle Detector• Observation of Large CP Violation
• Rare B Decays• Conclusion
Today’s Main Topic
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
• Introduction
• KEKB Accelerator and Belle Detector• Observation of Large CP Violation
• Rare B Decays• Conclusions
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
A World-Wide Activity Involving 50 Institutions
The Belle Collaboration
�����������
KEK
→ room for additional 300 physicists available �
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
KEKOsaka
Typhoons !
Closer Lookon 9. Sep, 2001…
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
~1km
Much closer look at KEKKEK KEKB Collider
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
The Belle Detector
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
Kobayashi-Maskawa and CPV
=
b
s
d
VVV
VVV
VVV
b
s
d
tbtstd
cbcscd
ubusud
’
’
’
������������ �����������������������
φ1
φ2
φ3
Vtd Vtb
Vcd Vcb
Vud Vub*
*
*
1) Discover / Establish CPV2) Precise/Redundant Measurement of CKM elements : angles and lengths3) Beyond SM
�� �����������CKM
matrixUnitaritytriangle
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
The Rules of the CPV Game• Find a decay mode which has two decay paths with
different weak phases (i.e. one of them has Vub or Vtd).• Two amplitudes should be similar for sizable interference.• Two paths should have “static” phase difference.
Example : B+ → K+π0 and B− → K−π0
Γ(B+ → K+π0) - Γ(B− → K−π0) = 4|T||P|sin(φ3)sin(s’-s)Large Uncertainty !
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
Time-dependent CP Violation
B0
B0 B0
Vcb
VtbV*
V*Vtb
J/ψ
J/ψKS
KS
+td
td
��������������������
∝ V*2td
∆mB is the origin of “static” phase difference.No hadronic uncertainty !
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
Large BB Mixing !
ARGUS (1987)
r = (N(BB)+N(BB)) /N(BB)
= 0.21 ± 0.08
(103pb-1 on resonance)
∆mB0 = (0.472 ± 0.017) ps-1
(PDG2000)
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
Appropriate BB Mixing !
Large enough and small enough(It is a miracle to me.)
Maximal CP at 3.3 psB0 Lifetime = 1.55ps
sin∆mt = 1
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
Principle of the Measurement
t ≈ ∆z/c
Flavor-tag decay(B0 or B0 ?)
J/ψ
KS
B - B B + B
= (1-2w)sin2φ1= (1-2w)sin2φ1
e−
e+
������������
∆zt=0
fCP
βγ
∆t from ∆z
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
Experimental Challenges
B(tag)decays
B(cp)decays
Υ(4s)prod.pt. Z2Z1
+Z
∆z
e- e+
deca
y ra
te
proper time difference ∆t (ps)
z ≈ c t(~200µm at Belle)
1) Copious B pair production, efficient B reconstruction2) Efficient and correct flavor tagging3) Observation of time-dependent CP asymmetry in B decays to a CP eigenstate with good vertex resolution
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
• Introduction
• KEKB Accelerator and Belle Detector• Observation of Large CP Violation
• Rare B Decays• Conclusions
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
KEKB asymmetric e+e− collider
TSUKUBA Area (Belle)
HER LERInteraction Region
OHO Area
High Energy Ring (HER)
for Electron
Low
Ene
rgy
Ring
(LER
)
for P
ositr
on
NIKKO Area
Electron Positron
e +/e -
(TRISTAN Accumulation Ring) W
IGG
LE
R
RF
WIG
GL
ER
RF
RF
R
F
RF RFFUJI Area
HER LERLinac
•Two separate storage ringse+ (LER) : 3.5 GeVe− (HER) : 8.0 GeV
•ECM : 10.58 GeV at Υ(4S)•Luminosity
•target: 1034 cm-2s-1
•achieved:4.5x1033cm-2s-1
•±11 mrad crossing angle •Small beam sizes:
σy ≈3 µm; σx ≈ 100 µm
World Record
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
KEKB performance
230pb-1/day→
32.8fb-1→
Integrated luminosity/day
Total accumulated luminosity
~80fb-1 expected by Summer 2002
The world record
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
KEKB’s Special Features
• Small beam sizes ⇒ low beam currents– 4.5x1033 with less than 1 Amp in each ring
• ± 11 mrad beam crossing angle
– No strong bending magnets near the IR– Fewer spent particles into Belle
– Synchrotron X-rays easily handled
22mrad
e-e+
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
Belle Detector Performance� Silicon Vertex Detector (SVD)
� Impact parameter resolution : 55µm for p=1GeV/c at normal incidence
� Central Drift Chamber (CDC)� (σPt/Pt)2 = (0.0019Pt)2 + (0.0034)2 (Pt in GeV/c)2
� K/π separation with� dE/dx in CDC (σdE/dx =6.9%)� TOF (σTOF = 95ps)� Aerogel Cerenkov (ACC)
� Efficiency = ~85%,Fake rate = ~10% up to 3.5GeV/c
� γ, e± with CsI crystals (ECL)� σE/E ~ 1.8% @ E=1GeV� e± : effic. > 90% w/ ~0.3% fake for p > 1GeV/c
� KL and µ± with KLM (RPC chambers)� µ± : effic. > 90% with ~2% fake at p > 1GeV/c
6m
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
Belle SVD (3 layers of DSSDs)
S/N = 20~40, Occupancy < 4%
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
Belle SVDZ Impact Parameter Resolution (Real Data)
0
25
50
75
100
125
150
175
200
225
250
0 1 2 3 4 5 6 7 8pβ*sin(Θ)5/2 (GeV/c)
Res
olut
ion
(µm
)
- cosmic ray- γγ → 4π
36 ⊕ 42/pβ*sin(θ)5/2 (µm)
R-Phi Impact Parameter Resolution (Real Data)
0
25
50
75
100
125
150
175
200
225
250
0 1 2 3 4 5 6 7 8pβ*sin(Θ)3/2 (GeV/c)
Res
olut
ion
(µm
)
- cosmic ray- e+e- → µ+µ-
- γγ → e+e-
19 ⊕ 50/pβ*sin(θ)3/2 (µm)
Z rφ
Impact parameter resolution
Sufficient to measure CP violation
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
• Introduction
• KEKB Accelerator and Belle Detector• Observation of Large CP Violation
• Rare B Decays• Conclusions
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
Summary of data samples
3 data sets were used:Set 1: 10.5 fb-1 (June 1999-July 2000)Set 2: 10.6 fb-1 (Oct 2000-May 2001)Set 3: 8.0 fb-1 (May 2001-July 2001)
Total: 29.1 fb-1 (corresponds to 31.3 million BBbar)
All data samples were analyzed and reconstructedwith the same consistent procedure.
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
!���"� � #�$�%�������&�����
BCP → J/ψ KS(→π+π− & π0π0) ψ(2S)(→l+l− & J/ψπ+π−) KS χc1(→J/ψγ) KS ηc(→KSK+π−, K+K−π0) KS J/ψ KL
J/ψ K*0 (→KSπ0) (mostly)
ξ f = �
ξ f=��
B � CP Eigenstate Decays
CP odd
CP even
b c
sc
d d K0
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
���������: B0 → J/ψ Ks(→π+π− )
��������������������������������������
Ks→π+π−
σ~4MeV/c2 Belle
J/ψ→µ+µ−
J/ψ→e+e−
σ~11MeV/c2
σ~10MeV/c2
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
B0 → J/ψ KS(→π+π− ) (cont’d)
Energy difference:
Beam-constrained mass:
457 events~3% bkgd
2/
2 )()2(SKJCMbc ppEm
�� +−= ψ
2/ CMKJ EEEES
−+≡∆ ψ
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
B0 → J/ψ Ks(→π+π− ) Event Display
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
All except J/ψ KL
457 candidates ~12 background(Purity = 97%)
B0 → J/ψ Ks(→π+π− )
290 candidates46 background(Purity = 84%)
B0 → other modes
Belle
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
B0 → J/ψ KL
• J/ψ →l+l− + KL2) Assume B�J/ψ KL: compute PKL3) Remove reconstructed B → J/ψ K, J/ψ K*, …4) Cut on a likelihood based on kinematical and shape quantities5) Plot P* =|P J/ψ + PKL|
B
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
B0 → J/ψ KL signal yield
569 total events346 signal
(Purity = 61%)
B0 → J/ψ KL
PB =| PJ/ψ + PKL|
Belle
PB(cms)
* * *Nsig = 346 events
Nbkg = 223 evts
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
Flavor-tag the other B meson
�Inclusive Leptons:�high-p l− b� c l− ν�intermed-p l+ s l+ ν
�Inclusive Hadrons:�high-p π+ B0�D(*)− π+, D(*)− ρ+, etc.�intermed-p K+ K+ X, π+π0
�low-p π− D0 π−
' ���� �������������
Use inclusive flavor-specific properties:
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
2-level Multi-dimensional Flavor Tagging
q = +1 ⇒ Btag
q = −1 ⇒ Btagr=(1-2w)MC
Lookup tablesπs Λ K Lepton
6 regions
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
Determination of wrong tag fraction wl
obtain w from B⇔B mixing amplitude: (1-2wl)cos(∆md ∆t)
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
Dilution : Measured vs. Expected
• Uses all events– Efficiency > 99%
ε effective = 27.0 ± 1.2%• Includes correlations• Use MC-r as a classifier
• Use data-w for CP fits
������������� r ≈ 1-2w �����������������1-
2wl
r
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
• For CP-side, use J/ψ�l+l−
– Reject poorly fit events.
δzCP ≈ 75 µm (rms)• For Tag-side
– use well fit tracks– iterate: discard worst track– δztag ≈ 140 µm (rms)
• Require |zCP - ztag|<2mm (≈10τB)
σ ∆t ≈ 1.5 ps
• Tails ≈ 3%; Effic. ≈ 85%
Vertex Reconstruction
��������(()*��+����������������������
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
Validation: B lifetimes
B�D*lν
τB0 = 1.55 ± 0.02ps τB+ = 1.64 ± 0.03psPDG: 1.55 ± 0.03ps PDG: 1.65 ± 0.03ps
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
Summary so far
• CP eigenstates with high purity.� Purity ~ 90% except for J/ψ KL (~60% for J/ψ KL )
• Efficient flavor tagging.� Effective efficiency = 27.0%
• Efficient vertexing with good resolution
• B lifetime measured precisely (high stat. control sample)
Everything is ready. Now let’s open the box !
1137 candidate events
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
Combine q, ξf & ∆t
raw data
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
CP is violated in B decays
•Large effect
•Apparent even in the raw data
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
Event-by-event Likelihood
’’’
’’
))()(
)()()1((
tdttRtPf
ttRtPfL
bkbkbk
sigsigbki
∆∆−∆⊗∆+
∆−∆⊗∆−= ∫
)()1(2/)( / tfeftP bkgt
bkbkg ∆−+=∆ ∆− δτ τ
ττ
))sin()2sin(
)21(1(2
1)(
1
/
tm
wqetP
d
ft
Bsig
B
∆∆×
−−=∆ ∆−
φ
ξτ
τ
Taken from data
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
sin2φ1 value that maximizes Πi Li
sin2φ1 = 0.99 ± 0.14 (stat) ±0.06(sys)
curves from
unbinnedfit
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
Confidence intervals
Belle c
entra
l
valu
es
1σ
1σ
95%
95%
Ciuchini et al(indirect
constraints)
1≥ sin2φ1 ≥ 0.70(95% C.L.)
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
asymmetry plot: all data
Result from global fit (sin2φ1=0.99)
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
Control sample: B0→non-CP states
“sin2φ1”
0.05±0.04
(statisticalerror only)
use: B0�D(*)−π+, D*−ρ+, D*−l+ν, J/ψK*(K+π−)
~17K events
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
Compare CP –1 and CP+1
CP-1
CP+1
sin2φ1
0.84±0.17
1.31±0.23
(statisticalerrors only)
Asy
mm
etry
opposite!
![Page 46: CP Violation and Rare B Decays at Belle DESY Seminar 11 ... · DESY Seminar 11 Sep, 2001. CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka) Outline • Introduction](https://reader033.fdocuments.us/reader033/viewer/2022052000/6012517325198754f62fd62f/html5/thumbnails/46.jpg)
CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
sin2φ1 from various subsamples
(statistical errors only)
q=+1 560 evts
q=−1 577 evts
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
If |?| is allowed to float, (i.e. a cos(?m t) term)
14.099.02sin 1 ±=φ
The CPV asymmetry is unchanged.
09.003.1 ±=λ
Test of Direct CP Term
![Page 48: CP Violation and Rare B Decays at Belle DESY Seminar 11 ... · DESY Seminar 11 Sep, 2001. CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka) Outline • Introduction](https://reader033.fdocuments.us/reader033/viewer/2022052000/6012517325198754f62fd62f/html5/thumbnails/48.jpg)
CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
CP fit : Systematic Error
±0.06Total
±0.01∆md and τB0 errors
±0.01Background shapes
±0.02KL background fraction
±0.02Resolution function
±0.03Flavor tagging
±0.04Vertex algorithm
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
Conclusions on CPV
�CP is violated in B decay
�sin 2φ1 is large:
0.99 ± 0.14 ± 0.06
>6σ!!
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
• Introduction
• KEKB Accelerator and Belle Detector• Observation of Large CP Violation
• Rare B Decays• Conclusions
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
B→ ππ, ρπ
φ1
φ2
φ3
Vtd Vtb
Vcd Vcb
Vud Vub*
*
*
B0 → D*+D(*)-(K)B0 → η’Ks, φKs
B0 → D(*)-l+ν, dileptons
B- → DCPK-
B→ ππ/KπB→ 3 body
B→ πlνB→ Dsπ
fB: B→ lν(B→ ργ)
EM/EW Penguin : B→ Kxγ, B→Kl+l-
Goals of Rare B Decay Program1) Discover / Establish “Direct” CPV2) Precise Measurements of CKM elements :
→ angles and lengths3) Beyond SM
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
Belle 2001 Summer Results(2001 Lepton-Photon Conferences)
35 contributed papers(5 charm, 3 τ, 2 two-γ physics)[4 final results - sent to journal ]
[see Web: http://belle.kek.jp/conferences/LP01-EPS for the datails of analyses and results ]
14 First Observations !
In addition to the observation of large CPV,
![Page 53: CP Violation and Rare B Decays at Belle DESY Seminar 11 ... · DESY Seminar 11 Sep, 2001. CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka) Outline • Introduction](https://reader033.fdocuments.us/reader033/viewer/2022052000/6012517325198754f62fd62f/html5/thumbnails/53.jpg)
CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
Importance of Vub Measurement
Belle’s 1σ band(both sol’ns)
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
Towards |Vub | : B0→ π-l+ν
GeV/c2
GeV/c2
Important to check large sin2φ1update 21.3 fb-1
Missing mass recon.
Mmiss2= Emiss
2 - pmiss2
< 2 GeV
107 ± 16 signals
Br = (1.28 ± 0.2 ± 0.26) x10-4
B0→ π-l+ν
pl > 1.2 GeVpl + pπ > 3.1 GeV
ε(trk/g rec.)
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
-0.30 -0.20 -0.10 0.00 0.10 0.20 0.30
∆E (GeV)
0
2
4
6
8
Num
ber
of e
vent
s Ds πD π
D ρ
Towards |Vub | : B0→ Ds π-
B0
π
Ds
Vub
Tree dominant (No Penguin)
Ds → φπ, K*0K+, KsK+
6.3 ± 3 evensBr < 1.1 x10-4
(CLEO:< 2.7 x10-4 )
About to see signal !
21.3 fb-1
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
Towards φ3 : B–→ DCPK–
0
10
20 (a) D o → K -π+
B - → D oK -
Can
dida
tes/
10
MeV
0
2
4 (b) D o → K -K +
0
5
-0.2 -0.1 0 0.1 0.2
(c) D o → π-π+
∆E (GeV)
12 ± 4 ev
21.3 fb-1
2) B→ DCPK decay
DCP→ K+ K–, π+π−
(Br ~ 1%)85 ± 10 ev
5 ± 5 ev
First Observation
W
�
�u
B�
b
�u
D0
cs
K
�
�u
W
�
�u
B�
b
�u
K
�
s�c
�D0
u
Vub
σ
1) B- → D0K (ICHEP2000) [PRL]
DCP = (D0 + D0)/√2 –
Br(B– → DCPK–) – Br(B+ → DCPK+)Br(B– → DCPK–) + Br(B+ → DCPK+) = 0.04 + 0.40(stat) ± 0.15(syst)
– 0.35
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
-0.30 -0.20 -0.10 0.00 0.10 0.20 0.30
∆E (GeV)
0
4
8
12
16
20
24
Eve
nts
/ 20
MeV
(e) D0ω Belle
D(*)0X0 decays :
-0.30 -0.20 -0.10 0.00 0.10 0.20 0.30
∆E (GeV)
0
5
10
15
Eve
nts
/ 20
MeV
(c) D0η Belle
-0.30 -0.20 -0.10 0.00 0.10 0.20 0.30
∆E (GeV)
0
20
40
60
Eve
nts
/ 20
MeV
(a) D0π0 Belle
128±18 ev 30±9 ev 18±7 evσ σ σ
Br = 2.9 ±0.4±0.6 1.7 ±0.6±0.4 3.4 ±1.3±0.8 (x10-4)
First Observation
Color suppressed modes:~0.1x Non-suppr. mode W
�
�d�B0
b
�dD+
cd
��
�u
W
�
�d
�B0b
�d�0
d�u
D0
c
Evidence for: D*0π0(3.2σ), D*0ω(3.6σ), D*0η(3.8σ)
Step towards D0K/DKs
D0π0 D0ω D0η
-
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
b → sss (uus) b → suu, sdd uus b → ucd, ccd b → dds, uus, dds
• For sin2φ1 analysis
• “Rare” decays
Bcp events at Belle as of July 2001
sin2φ1 = 0.99 ±0.14 ±0.06
61%
84%
97% 29.1fb-1457ev.J/ψ Ks(→π+π− )
29.1fb-1569ev.J/ψ KL
29.1fb-1290ev.Other (cc) Ks
candidates purity int. lumi.
21.3fb-182% 27ev.D*D(*)
10.4fb-167% 12ev.Ks π 0
63%
80% 21.3fb-1 10ev.φ (→K+K− ) Ks
10.4fb-1 26ev.η’ Ks
Penguin Tree
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
Clear Manifestation of New Physics !
cc
s
bNo new phase
vs.CP eigenstates (or flavor non-specific states) with any otherdecay diagrams, such as the following;
s or d
qb q
s or db
γ
Acp(J/ψ Ks) ≠ Acp(Bcp with Penguin)
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
B0 → η’ Ks (10.4fb-1)
Origin of the large branching fraction is not understoodyet. It may include contribution from new physics !
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
0
5
10
15
20
25
30
35
40
-1 -0.8 -0.6 -0.4 -0.2
a
ytitl
e
-1
0
50
100
150
200
250
300
0
50
100
150
200
-1 -0.8 -0.6 -0.4 -0.2
aytit
le
c
ytit
le
-1
B0 → D*+D- ⇒ φ1
Partial Reconstruction Technique :
φ1 measurements with other diagramsAll(no tag)
continuumContinuum subtractedLepton tag
πs
D-(full)
D*+
D0
α
cosα cosα
Use only slow π and D-(full)
Br=1.84 ±0.46±0.68 (x10-3)
First Observation
36 ± 11 ev 224 ± 87 ev
21.3 fb-1(New)
To be used for CP
corresponds to ~100 ev
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
B0 → D*+D(*)- ⇒ φ1Full Reconstruction : better S/N
5.200 5.225 5.250 5.275 5.300Mbc (GeV/c2)
0
1
2
3
4
5
6
En
trie
s/(2
MeV
/c2 )
Belle
a)
5.200 5.225 5.250 5.275 5.300Mbc (GeV/c2)
0
1
2
3
4
5
En
trie
s/(2
MeV
/c2 )
Belle
a)
B0 → D*+D- B0 → D*+D*-
Confirm partial Recon.
11.2 ± 4 evσ
11.0 ± 3.7 evσ
Br=1.04 ±0.38±0.22 (x10-3)
Br=1.21 ±0.41±0.27 (x10-3)First Observation
D*+ → D0 π+ only⇒ add D*+ → D+ π0 modeNeed angular anal. for φ1
21.3 fb-1
D0 →
K- π+
K- π+ π0
K- π+ π+ π−
(New)
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
EW Penguin : b→ s l+ l-
Awaited mode sensitive to SUSY after b→ sγ (consistent to SM)
Exclusive mode: B→ K(*) l+ l-
Mbc (GeV/c2)
Eve
nts
/ 2.5
MeV
/c2
B→ K* µ+ µ− B→ K* e+ e-: < 3.0 (2.8 )+2.9- 2.1 : < 5.1 (5.5 )+3.7
- 3.0
B→ K µ+ µ− B→ K e+ e-
9.5 ev+3.7- 3.1
: < 1.2 (2.6 )+2.7- 2.0: 0.99 +0.39 +0.13
- 0.32 - 0.15
x10-4
B→ K+ µ+ µ−
B→ Ks µ+ µ−
combined
σ
First Observation
29.1 fb-1
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CP Violation and Rare B Decays at Belle Sep. 2001 M. Hazumi (Osaka)
Conclusions
• Large CPV in B decays !
• 14 First Observations mainly on Rare B Decays• ~80fb-1 by Summer 2002 !
• Precision measurements of sin2φ1• Vub, φ2 to constrain the Triangle• Mixing-induced CPV in penguin diagrams• Search for direct CPV• More rare decays
sin2φ1 = 0.99 ± 0.14 ± 0.06
Exciting new results in the near future !