Moriond EW, 3 Mar 2008 Tagir Aushev (EPFL, ITEP) 1
B → KS 0 0
B → KS KS
B → KS 0
B → D*+ D*-
B → a1 , a1K, b1 , b1 K...(4S) → BCP BCP
Measurements of φ1 and φ2
Tagir AushevFor the Belle Collaboration
(EPFL, LausanneITEP, Moscow)
Moriond EW, 3 Mar 2008 Tagir Aushev (EPFL, ITEP) 2
† *1 0ud cd cbV V V V V *ubV tdV *
tbV
,
0,1
0,0
ud
cd cb
V
V V
*ubV tb
cd cb
V
V V
tdV
*
*
* *
* *arg , arg , argtd ubtb cd cb ud
ud tub td b cd cb
V V
V V
V V V V
V V V V
relative
magnitudes
CKM matrix & unitary triangle
Moriond EW, 3 Mar 2008 Tagir Aushev (EPFL, ITEP) 3
CP Violationin the Standard Model
• Triangle is well measured• φ1() mainly from B0→J/Ψ KS “golden mode”• Smaller and smaller room for the vertex position, but it is still in• New decay modes are examining to find a New Physics
Moriond EW, 3 Mar 2008 Tagir Aushev (EPFL, ITEP) 4
TCPV measurement on B-factory
B’s are produced in a boosted frame t is measured from vertex positions
B’s are entangled flavor of B1 at time t2 is determined by B2 decay
Moriond EW, 3 Mar 2008 Tagir Aushev (EPFL, ITEP) 5
8GeV (e-) 3.5GeV (e+)
Silicon Vertex Tracker
5-layer, double-sided strips
Drift Chamber40-layer, small
cell
DIRC (PID)quartz
Cherenkov detector
EM CalorimeterCsI crystals
Flux ReturnRPC and
LST instrument
ed iron
1.5 TSolenoi
d
Belle & BaBar B-factories
Moriond EW, 3 Mar 2008 Tagir Aushev (EPFL, ITEP) 6
BaBar collected 510 fb-1
Lpeak
=1.71×1034cm−2 s−1
∫Ldt=770 fb−1
Current luminosities
Moriond EW, 3 Mar 2008 Tagir Aushev (EPFL, ITEP) 7
BD(0,+)D0
After evidence for DCPV in BD-
D+ recently shown by Belle all BDD decays has a special interest
B.R. and charge asym for BD+D0 were updated by Belle:
B.R. = (3.85 ± 0.31 ± 0.38)·10-4
BaBar’06: (3.8 ± 0.6 ± 0.5)·10-
4
A = 0.00 ± 0.08 ± 0.02BaBar’06: -0.13 ± 0.14 ± 0.02
Also an upper limit for BD0D0 :B.R.<0.43·10-4@90%C.L.
hep-ex/0802.2988
Moriond EW, 3 Mar 2008 Tagir Aushev (EPFL, ITEP) 8
TCPV in B0D*+D*–
B0D*+D*– is b ccd transition and so sensitive to sin2 just like the “Golden” B0cc K0 making it an important check
Series of papers were published by Belle and BaBar
Recently the results are updated with latest statistics
Belle result is the first time presented
Belle Preliminary
N=545 +- 29
Phys.Rev.D76:111102,2007
Moriond EW, 3 Mar 2008 Tagir Aushev (EPFL, ITEP) 9
BaBar: R = 0.143 0.034 0.008
Belle: R = 0.116 0.042 0.004
Since it is a decay of S VV CP-eigenstate depends on angular momentum of the VV system:
• Separating the CP-odd fraction,
R, is done via a 1D angular
analysis
Helicity of B0D*+D*–
Belle Preliminary
Moriond EW, 3 Mar 2008 Tagir Aushev (EPFL, ITEP) 10
TCPV in B0D*+D*–
S=-sin21 A=-C
BaBar -0.66 ± 0.19 ± 0.04 +0.02 ± 0.11 ± 0.02
Belle -0.93 ± 0.24 ± 0.15 +0.16 ± 0.13 ± 0.02
tmtmtt
tttA dd
fBfB
fBfBCP
CPCP
CPCP
cossin)()(
)()()(
00
00
AS
Belle Preliminary
Moriond EW, 3 Mar 2008 Tagir Aushev (EPFL, ITEP) 11
Penguin dominated B decays are sensitive to NP
+
New Physics may introduces extra CP phase in the decay
Deviation of Time-dependent CP violation parameters from the SM expectation Hint of New Physics
Searches for a New Physics
SM
s,dq
qNP
s,dq
q
Moriond EW, 3 Mar 2008 Tagir Aushev (EPFL, ITEP) 12
TCPV in B0 → KS00 :bsqqNsig = 307±32
22Bbeambc pEM
Belle +0.43+/-0.49+/-0.09BaBar +0.72+/-0.71+/-0.08Average+0.52+/-0.41
Belle -0.17+/-0.24+/-0.06BaBar -0.23+/-0.52+/-0.13Average -0.18+/-0.22
LR>0.9, good tag
X
SM expectation
>2 from the SM
Phys.Rev.D76:071101,2007
Belle Preliminary
S=-sin21
A=-C
Moriond EW, 3 Mar 2008 Tagir Aushev (EPFL, ITEP) 13
TCPV in B0→KS π0
Nsig = 459 ± 29B.R.= (10.3±0.7±0.6)·10-6
Belle +0.33+/-0.35+/-0.08BaBar +0.40+/-0.23+/-0.03
Belle -0.05+/-0.14+/-0.05BaBar -0.24+/-0.15+/-0.03
S=sin21
A=-C
Phys.Rev.D77:012003,2008
Phys.Rev.D76:091103,2007
Moriond EW, 3 Mar 2008 Tagir Aushev (EPFL, ITEP) 14
~90o±10o
Measurements of φ2
was measured in and systems
The same matrix elements are also involved to the B decays to axial vectors a1, b1 …
Some of them can be used only with much larger statistics
Moriond EW, 3 Mar 2008 Tagir Aushev (EPFL, ITEP) 15
Measurement B a1
6
110
10)3.26.19.14(
).(.).(.
aRBaBRB
First time-dep CP asymmetry in B → a1+
0B
0B
PRL 98, 181803 (2007)
BaBar
?,779eff
608 ± 53 B0→a1 (461 ± 53 flav.-tagged)
Belle Preliminary
Moriond EW, 3 Mar 2008 Tagir Aushev (EPFL, ITEP) 16
B→00
Latest result from Belle:
Moriond EW, 3 Mar 2008 Tagir Aushev (EPFL, ITEP) 17
B decays to light mesons
B→b10π+: (6.7±1.7±1.0)·10-6
B→a10π+: (20.4±4.7±3.4)·10-6
B→b10K+: (9.1±1.7±1.0)·10-6
B→a1+K0: (34.9±5.0±4.4)·10-6
B→b1-π+: (10.9±1.2±0.9)·10-6
B→a1-π0: (13.2±2.7±2.1)·10-6
B→b1-K+: (7.4±1.0±1.0)·10-6
B→a1-K+: (16.3±2.9±2.3)·10-6
No charge asym’s foundPRL 99:261801, 2007PRL 100:051803, 2008PRL 99:241803, 2007
Moriond EW, 3 Mar 2008 Tagir Aushev (EPFL, ITEP) 18
CPCP Violating Decays of Violating Decays of thethe(4S)(4S)
CP violation !!
J/KS
11
J/KS
21
CP1 CP1
J/KL
11
J/KL
21
CP1
Y(4S)CP1
J/KS
11
CKS
C1KS
(2S)KS
21
CP1
B0
B0_
Moriond EW, 3 Mar 2008 Tagir Aushev (EPFL, ITEP) 19
Partial reconstruction
Partial reconstruction
Full reconstruction
+
-
KS
J/
+
-
+
-
J/c
KSSignal MC
J/(ll)KS
J/(any)KS
Y(4S)
_B0
B0
About 40 times higher eff. than full reconstruction method
1.1(0.6) inclusive-J/(c) events in 535 million Y(4S) decays
Moriond EW, 3 Mar 2008 Tagir Aushev (EPFL, ITEP) 20
Nsig=-1.5 -2.8 events+3.6
Br(Y(4S)B0B0J/KS+J/(c)KS) 4x107 (90%C.L.)
SM prediction : 1.4x10-7
Results with 535M Y(4S) decaysControl sample
B D(*)- and D*- B0 c KS and J/ KS
Nsig=35 ±16 events
B0 J/KS
B0 J/(c) KS
With 30 billion Y(4S) (30ab-1),
such decays will be observed
with 5 significance
Moriond EW, 3 Mar 2008 Tagir Aushev (EPFL, ITEP) 21
Summary
• CP violations was measured in various B decays
– Both mixing-induced & direct CPV observed
• Excellent agreement with Standard Model
– Small room for New Physics remains in flavour sector
• Next order of the statistics is needed to give an answer for the New Physics existence
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