Moriond EW, 3 Mar 2008Tagir Aushev (EPFL, ITEP)1 B → K S 0 0 B → K S K S B → K S 0 B...

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)


† *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


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


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


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


BaBar collected 510 fb-1

Lpeak

=1.71×1034cm−2 s−1

∫Ldt=770 fb−1

Current luminosities


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


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


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


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


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


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


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


~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


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


B→00

Latest result from Belle:


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


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_


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


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


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

Moriond EW, 3 Mar 2008Tagir Aushev (EPFL, ITEP)1 B → K S 0 0 B → K S K S B → K S 0 B...

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Transcript of Moriond EW, 3 Mar 2008Tagir Aushev (EPFL, ITEP)1 B → K S 0 0 B → K S K S B → K S 0 B...