recent results on b decays

ICHEP 2004, Beijing 11

Recent Results on B decaysRecent Results on B decays

Y.Sakai (Belle/KEK)

- Rare B Decay Highlights 　　　　　　　 + Belle b sqq Time-dependent CPV --


OutlineOutline

Introduction KEKB and Belle Detector [PEP-II/BaBar: by Giorgi]

New Results on Rare decays (Belle/BaBar) (Highlights)

Updated/New results on b s TCPV from Belle

Contributed papers available Belle: http://belle.kek.jp/conferences/ICHEP2004/ BaBar: http://www.slac.stanford.edu/BFROOT/ www/Public/ichep2004/

Apology; cannot cover all of the many interesting results from the parallel sessions

[Results are preliminary unless references are given]


B Decays & the SMB Decays & the SM

Electro-weak

Hadrons

Quark levelQuark level

Final stateFinal state QCD/LatticeNew Resonances

QCD/LatticeNew Resonances

b-quark: Heavy variety of decay modes

Rich field for fundamental SM parameters

1

2

3

Vtd Vtb

Vcd Vcb

Vud Vub*

*

*


B decays & New PhysicsB decays & New Physics

Experimentalmeasurements SM predictionsagree?

Deeper understandingDeeper understandingNew Physics ?New Physics ?

YesNo

Key point: ANP ~ ASM (small/forbidden)

b t s,dg,,Z

WPenguin

b x s,d+

New particle, Phase

http://www.dex.ne.jp/mantan/search/std2_search_preview.jhtml?start=10&lastServiceTime=1090676093961&number=1


KEKB ColliderKEKB Collider

~1 km in diameter

Mt. Tsukuba

KEKBBelle

8 GeV e8 GeV e-- x 3.5 GeV e x 3.5 GeV e++

@ 1.2A x 1.6A@ 1.2A x 1.6ALLpeakpeak = 1.39 x 10 = 1.39 x 1034 34 secsec-1-1cmcm-2 -2

11mrad crossing

~287 fb-1274M BB253 fb-1 on Y(4S)

28 fb-1 below Y(4S)

-

http://kekb.jp/


Continuous InjectionContinuous Injection[CERN courier Jan/Feb 2004]No need to stop run

Always at ~max. currents, luminosity~30% more ∫L dt

both KEKB & PEP-II

HER current

LER current

continuous injection (new)normal injection (old)

Luminosity

0 12 24Time

~1 fb-1/day ! (~1x106 BB)-

http://kekb.jp/


Belle DetectorBelle Detector

/ KL detection 14/15 lyr. RPC+Fe

Central Drift Chamber small cell +He/C2H5

CsI(Tl) 16X0

Aerogel Cherenkov cnt. n=1.015~1.030

Si vtx. det. 3(4) lyr. DSSD

TOF conter

SC solenoid 1.5T

8 GeV e

3.5 GeV e


SVD UpgradeSVD Upgrade

SVD1 SVD2

• 1 MRad >20 MRad• 3 layers 4 layers • 23º<<139º 17º<<150º• Rbp = 2.0 cm 1.5 cm

Better I.P. resolutions

2003 summer

Impact parameter resolution

r Z

152M BB pairs with SVD1+ 122M BB pairs with SVD2

__


B-meson ReconstructionB-meson Reconstruction

Energy difference:

Beam-constrained mass:

Utilize special Kinematicsat Y(4S)

222 )()( iCMbc pEM

2CMi EEE

(ES)


Continuum SuppressionContinuum Suppression

e+ e-

e+ e-

qq

Signal B

Other B

Dominant Background for rare decays:

Continuum

Jet-like

BB

spherical

e+e → qq “continuum” (~3x BB)

To suppress: use event shape variables

continuum

Y (4S)


B B

Penguin d

b

d

s/d

u

u

W

B0d -

+

Vus/d

Vub

Tree

• Simplest charmless rare decay modes• Tree - Penguin interference Direct CP Violation

Key prediction of Kobayashi-Maskawa model

Key prediction of Kobayashi-Maskawa model

Understanding of Penguin

_ _ (B f ) (B f ) _ _ (B f ) (B f )

ACP =

Anomaly (New Physics)

B0d

d

b

du

u

W

g +

-

Vts/dVtb

ts/d




ACP(B0 K)ACP(B0 K)

2nd Evidence for DCPV at Belle ! [A() 3.2]

ACP = -0.101 0.025 0.005 [PID efficiency bias correction: A = -0.01 0.004]

274M BB New

3.9 significance[submitted to PRL]

B0 K _B0 K

Signal: 2139 53


B0 + CPV ResultB0 + CPV Result

A = +0.58 0.15(stat) 0.07(syst)S = 1.00 0.21(stat) 0.07(syst)

S

A

t (ps)

Direct CPV3.2

[PRL93,021801 (2004)]

good tag

152M BB


ACP(B K)ACP(B K)

ACP(K) = 0.04 0.05 0.02

274M BB New

K: 728 53

hint that ACP(K) ACP(K) ? (2.4)

Large EW penguin (Z0) ?

New Physics ?

[also seen by BaBar]

_d

d

K

u u

B sb


Observation of B0 00Observation of B0 00

274M BB, New

Evidence (LP03) Observation !

B = (2.32 ) x 10-6 Large Br established

Signal: 82 16 (6.0)

ACP = 0.43 0.51

uses same Flavor-tagging as TCPV analysis

1st measurement !

BaBar results & 2() Giorgi’s talk

Mbc[Belle-conf-0406]

Key mode for 2() in B CPV isospin analysis

0.440.48

0.220.18

0.170.16


B0 B0

First signals for B0

Nsig = 23 2.0 7.76.7

(4.5

B = (1.19 0.13) x 10-6

0.400.35

Nsig = 41 14 3 (3.5

B = (1.46 0.50 0.07) (<2.35) x 10-6

B0 00

B0 0+

224M BB

“pure b d Penguin”


Penguin Anomaly ? New physics effect ?K*(bsss) only ?-

B VV : Polarization PuzzleB VV : Polarization PuzzleNaïve Factorization : Longitudinal fL = 1 – O(1/mb

2)

fL(K*) ~ 0.5

QCD penguin annihilation: O(1/mb2) O(1)

f/ f = 1 + O(1/mb) ? fL(K) < fL(K*) ?[K: pure b s Penguin]

[e.g. A.Kagan hep-ph/0405134]

B+u

u

b

uss

W

g

*+

VtsVt

b ts

KfL 1Tree dominated

Penguin only

(BaBar/Belle)

s

ud

d

*0


KPolarizationKPolarization152M BB-

,Kmass region

peak: 6.3signif.2D(Mbc,E,) ML fit

Mbc, E signal region simultaneous fit to K* masses

K: 26.6 8.7(Stat. sig: 3.2)

[Belle-conf-0404]

EMbc

mass Kmass


KPolarizationKPolarization

2D(,K* helicity) ML-fit (Mbc, E, mass signal region)

fL =0.50 0.19 0.050.07 (3.1 away from fL= 1 )

B = (6.6 2.2 0.8 ) x 10-6

bkg (fixed)

K(fixed)

Transverse

Longitudinal

helicity K helicity

[Belle-conf-0404]

152M BB-


KPolarizationKPolarization　 89M BB-

Nsig = 141 2324 (>5

fL =0.79 0.08 0.04 0.02 B = (17.0 2.9 2.9 ) x 10-6

0.01.9

ACP = 0.14 0.17 0.04

[BaBar-conf-04/34]

ML fit to all distributionssimultaneously

BaBar + Belle likely fL < 1

BaBar + Belle likely fL < 1

non-resonantcontribution

1st observation


B K* : New Physics SearchB K* : New Physics SearchTransversity basis:

Angular distribution PK*( tr, tr, K* ; A0, A//, A)

A0 : longitudinal (CP= +1)A// : transverse CP= +1A : transverse CP= 1

2 sets _(B, B)

= f= (|A|2+ |A|2)/2, = (|A|2|A|2)/2

i = Im(AAi*+AAi

*), i = Im(AAi*AAi

*)//0 = Re(AA0

*+AA0*), //0 = Re(AA0

*AA0*)

Direct CPV

Triple-prod. (T-violation)

( |A|2+ |A|2 + |A|2 =1 ) “0” NP [e.g. London, Sinha2, PRD69,114013(04)]

(i = 0, //)

(12-1 parameters)


97 signals

1211

46 signals

98

B K*B K*[Belle-conf-0419]152M BB-

fL =0.51 0.06 0.04

confirm low fL

K*0

K*+


B K* : New Physics SearchB K* : New Physics Search

“0” NP

Triple product (T-conserving)

Triple product (T-violating)

f/ f ~ 1

FSI

[Belle-conf-0419]

152M BB-


B K* : New Physics SummaryB K* : New Physics Summary

arg(A/A) 2.34 0.23 0.05(-2.34) -2.21 0.22 0.05

arg(A/A) 2.47 0.25 0.05(0.67) 0.64 0.21 0.06

(* recalculated from fit values)

Belle (152M)BaBar (227M)

*

*

No indicationof NPexcept fL puzzle

“0” NP

BaBar/Belle consistent


Radiative & EW PenguinsRadiative & EW Penguins

EW

~1/100

Loops Sensitive to New Physics

K* TCPV

Br, ACP ~SM

b s penguin

b sl+l penguin

b d penguin

l+

l


B → K(*) l+lB → K(*) l+l

79 10signals

82 11signals

[Belle-conf-0415]

B (Kll)= (5.50 0.27 0.02)

274M BB

0.750.70

B (K*ll)= (16.5 0.9 0.4 )2.32.2

>10 signalsupdate

LP03: B Xsll, K(*)ll : Belle/BaBar Br, ACP ~SM

x 10-7


B → K* l+l:FB Asymmetry B → K* l+l:FB Asymmetry

( / 2) ( / 2)

( / 2) ( / 2)Bl Bl

FB

Bl Bl

A

AFB(K*ll ) : very sensitive to NP

that may not be seen in B(bs

First Look ![Belle-conf-0415]

274M BB

raw AFB

K*

q2

q2


274M BB

b → d: B → ()b → d: B → ()

B(B() = (0.72 0.27 )x 10-6 (1.9) [< 1.4 x 10-6 @90% CL]

+0.430.39

Suppress K* with PID and M(‘K’) cut

[Belle-conf-0401]

Simultaneous fit to 3 modes: (B() = (B++) = 2(B00) = 2(B0)

B(B() = (0.6 0.3 0.1) x 10-6 (2.1)[< 1.2 x 10-6 @90% CL]

|Vtd|/|Vts| [ A.Ali’s talk]

219M BB

[hep-ex/0408034]


b sqq Penguin CPVb sqq Penguin CPVBelle @LP03 (140 fb-1)

“sin21”= 0.96 0.51

B0 Ks

sin21=0.728 0.06

B0 J/Ks etc

3.5 deviation from the SM !

--

[PRL 91, 261602 (2003)]


Time-dependent CP ViolationTime-dependent CP Violation

ｆｃｐ

B0

B0mixing

=B0

B0 ｆｃｐ

+

+ New Physics with New Phase

Sbs sin21 , A can 0Sbs =sin21, A=0

SM: b s Penguin phase = J/KS

(b c)

tstb VV

Mixing induced CPV Direct CPVACP (t) = S sin(mt) + A cos (mt)

(TCPV)


B0 K0B0 K0

Similar to J/KL recon.+ sophisticated continuum suppression

includes Ks (Nsig=13 5)

KS

Nsig=139 14purity 0.63

pB*

Nsig= 36 15

KL

purity 0.17

274M BB


B0 K0 : CPV ResultB0 K0 : CPV Result

K0

KS + KL

: S (K0) = +0.06 ±0.33 ±0.09

A (K0) = +0.08 ±0.22 ±0.09 ~2.2 away from SM

KS + KL

: S (K0) = +0.06 ±0.33 ±0.09

A (K0) = +0.08 ±0.22 ±0.09 ~2.2 away from SM

Good tags

Poor tags

S = 0.736fit Good tags

274M BB


Checks: sin21 (B0 J/ KS/L)Checks: sin21 (B0 J/ KS/L)

SVD1: 152M BB

t (ps)

Good tags

SVD1

Validation of new data sample (SVD2)

SVD2: 122M BB

Good tags

SVD2

_

S = 0.696 0.061 (stat)

A = 0.011 0.043 (stat)

S = 0.696 0.061 (stat)

A = 0.011 0.043 (stat)

S = 0.629 0.069 (stat)A = 0.035 0.044 (stat)

S = 0.629 0.069 (stat)A = 0.035 0.044 (stat)

_

SVD2: S = +0.78 0.45 A =+0.17 0.33

SVD1:S = 0.68 0.46A = 0.02 0.28

many systematic checks, all ok

~2.3K0


B0’KS KKKSB0’KS KKKS

’KS KKKS



S = +0.65 0.18 0.04 S = +0.49 0.18 0.04 ( ) A = 0.19 0.11 0.05 A = 0.08 0.12 0.07

CP=+1: 1.03 0.15 0.05

“sin21”

Raw

Asy

mm

etry

Good tags Good tags

S = 0.736fit

0.170.0

Raw

Asy

mm

etry

(~0.5@SM) (~1.0@SM)

high statistics modes(excluded)

’

( , )

274M BB


B0KS f0(980)KSB0KS f0(980)KS

KS additional modesNsig=31 7

purity 0.56


f0(980)KS

S = +0.75 0.64 S = 0.47 0.41 0.08 A = 0.26 0.48 0.15 A = 0.39 0.27 0.08

“sin21”

Raw

Asy

mm

etry

Good tags

S = 0.736fit

0.130.16

Good tagsRaw

Asy

mm

etry

(~2.9@SM)(~0@SM)

274M BB


B0 KsKs0 0 B0 KsKs0 0

Ks track

IP profileB vertex

Vertexing by Ks only

KsKs00


S = +0.30 0.59 0.11 A = 0.12 0.20 0.07

Good tags

Validated by J/ Ks (use Ks only)

S = 0.736fit

Raw

Asy

mm

etry

“sin21”(~0.7@SM)

(+low purity: Nsig=83(0.17))

274M BB


Summary of b sqq CPVSummary of b sqq CPV--

2.4

“sin21” 274M BB

(A: consistent with 0)


B K* TCPV: New PhysicsB K* TCPV: New Physics

SM: polarized B0 & B0 opposite

S ≈ 2(ms/mb)sin 21 ≈ 4% A ~ 1%New Physics Large S, A

Analysis Technique: similar to B0 KsKs0 0

-

B0 K*[Ks0] Ks track

IP profileB vertex

[e.g. Atwood,Gronau,Soni]


B K*[Ks0] TCPVB K*[Ks0] TCPV


274M BB

S = 0fit

124M BB-[hep-ex/0405082]

Nsig=105 14

S = 0.25 0.63 0.14 S = 0.79 0.09 A = 0.57 0.32 0.09 = C A = 0.00 0.38

0.630.50

First step for new era of b s !


B decays: many new results from BaBar/Belle

- Evidence for Direct CPV, ACP(K+) ACP(K+) ? - B decay established, 1st measurement of ACP() - fL(K*) Polarization Puzzle: fL(K*0) < 1 No hint of T-violating NP in B K* - A first look at B K*ll FB-asymmetry - 1st B0 K*[Ks0] TCPV measurements

SummarySummary

Belle b sqq TCPV updates - S (K0) = +0.06 ±0.33 ±0.09 (~2.2 away from SM) - average of b sqq : +0.43 ± (~2.4 from SM)-

(Giorgi’s review for BaBar results)

0.130.11

More data needed to conclusively establish New Physics

-


Charmless B Br SummaryCharmless B Br Summary

HFAG P.Chang (NTU) J.Alexander (Cornell) J.Smith (Colorado)

Complete list (other Br & ACP )http://www.slac.stanford.edu/xorg/hfag/rare/ x10-6


BackupBackup


B PP/PV/VV SummaryB PP/PV/VV Summary ’

’

observed (>5)

evidence (>3)upper limit

Both, BaBar, Belle, CLEO

[extend to decays into scalar, axial-vector]DCPV: evidence in / only


B0 KS : Mass & Helicity B0 KS : Mass & Helicity

Helicity

bkg

Mass


B0 K0 : SVD1,2 B0 K0 : SVD1,2

SVD2: S = +0.78 0.45 A =+0.17 0.33

SVD1:S = 0.68 0.46A = 0.02 0.28

many systematic checks, all ok

~2.3

SVD1 only SVD2 only


B0 KS, KL : CPVB0 KS, KL : CPV

KL onlyK

S only

S = +0.00 ±0.33

A = +0.06 ±0.22

S = +0.00 ±0.33

A = +0.06 ±0.22−S= +2.3 ±2.0

A = +0.6 ±1.2

−S= +2.3 ±2.0

A = +0.6 ±1.2


B0 K : ValidationsB0 K : Validations

Lifetime fit w/ B →K±/KS

B →K± B →KS

B+ = 1.67

+0.12–0.11

B0 = 1.59

+0.20–0.19

Asymmetry fit w/ K±

S(K±) = –0.03 ±0.20

A(K±) = +0.22 ±0.15

Control sample


Systematic errors on SSystematic errors on SKs 0 K* Ks ’ Ks f0 Ks K0 K+K-Ks

VTX 0.02 0.06 0.01 0.01 0.02 0.01 0.01

flavor tag 0.01 0.02 0.04 0.01 0.01 0.01 <0.01

resolution 0.05 0.05 0.07 0.03 0.03 0.04 0.03

fit bias 0.03 0.03 +0.010.10

0.01 0.03 0.01 0.01

signal fraction

0.07 0.02 0.10 0.02 0.05 +0.080.06

0.02

physics parameters

0.02 0.01 0.01 <0.01 0.01 <0.01 <0.01

background t shape

0.04 0.03 0.02 <0.01 0.04 0.01 <0.01

tag side interference

<0.01 <0.01 0.01 <0.01 <0.01 <0.01 <0.01

TOTAL 0.11 0.10 +0.130.16

0.04 0.08 0.09 0.04

KKKS: effective sin21 0.17 for CP-even fraction


SVD2: lifetime & mdSVD2: lifetime & md

0B

B

dm

0B

B

dm

[ps]

[ps]

[ps1]

1.534 0.008 0.010

1.635 0.011 0.011

0.511 0.005 0.006

1.518 0.012

1.652 0.014

0.516 0.007

SVD1 _(152M BB)

SVD2 _(122M BB)

New detector resolution is well understood

SVD2 only

Belle preliminary

D0+, J/ K , D–+, D*–+/+, D*l

(stat)

(stat)

(stat)[Belle-conf-0436]


History of b sqq CPVHistory of b sqq CPV-


f0(980)KSMass didtributionf0(980)KSMass didtribution

f(f0KS) = 91%

f(KS) = 2.3%

fKS) = 4.8% f(fxKS) = 1.6%

fx

Non-f0 componentsare determined fromthe M() distribution [


Continuum SuppressionContinuum Suppression

LS/(Ls + LB )

Belle: cut on Likelihood Ratio

signal

signal

continuum

continuum

Fisher

BaBar: loose cut Fisher (or NN) pdf in fit

Event-shape variables combine Fisher

Flavor tagging info. also useful


CKM Matrix & UTCKM Matrix & UT

b

s

d

VVV

VVV

VVV

b

s

d

tbtstd

cbcscd

ubusud

'

'

'

2

2

)1(

2/

)(2/

AiA

A

iA

CKM matrix

Wolfenstein representation

Complex phase CP violation

1

2

3

Vtd Vtb

Vcd Vcb

Vud Vub*

*

*

Unitaritytriangle

()

() ()


BaBar B K*BaBar B K*use helicity basis angles:

Angular distribution PK*( 1,2 ,; A0, A//, A)

2 sets _(B, B)

227M BB

B0 K*0

201 signals

cos1 cos2

ACP = -0.01 0.09 0.02[hep-ex/0408017]

recent results on b decays

Documents

b s tcpv

b decaysy

pure b s penguine

p signal

s prl93

s significancesubmitted

giorgi new results

5t8 gev e