rare hadronic b decays

Liliana Teodorescu2

2 July 2004

IntroductionIntroduction Analysis methodAnalysis method BBuu and B and Bdd decays to mesonic final states decays to mesonic final states

(results and discussions)(results and discussions) ConclusionConclusion

Liliana Teodorescu3

2 July 2004

Rare B decaysRare B decays branching fractions (BF) less than 10-5

do not involve CKM favoured b->c transitions

Theoretical mechanismTheoretical mechanism CKM suppressed tree b->u transitions (T) loop (penguin) b->s or b->d transitions (P) interference between T and P => direct CP violation

;coscos21

sinsin2

)()(

)()(2

rr

r

fBfB

fBfBACP

Direct CP violation observableDirect CP violation observable

T

Pr

weak phase diff.

strong phase diff.

ACP sizeable when TP and 0,0

Liliana Teodorescu4

2 July 2004

Physics interestPhysics interest Standard ModelStandard Model

Precise tests of the theoretical predictions (small amplitude processes) Potential evidence for CP violation Constraints on CKM parameters – extraction of UT angles through

New PhysicsNew Physics New particles hidden in the loops Constraints on theoretical models

SM non-SMHiggs

SUSY

Covered in this talkCovered in this talk

direct measurements of the time-dependent asymmetries branching fraction dependence on the UT angles

BFs and ACP (time-integrated) (Babar, Belle, Cleo)

Observables Observables BF time-integrated CP asymmetry time-dependent CP asymmetry

Liliana Teodorescu5

2 July 2004

Signal isolationSignal isolation identification of reconstructed B with 2 almost uncorrelated kinematical var.

BBS )4(

beam-energy substituted mass (beam constrained mass – Mbc )

energy difference

Signal: mES= mB

Signal: E = 0

Background suppressionBackground suppression“continuum” events - non-resonant qqee

),,,( csduq

B decays: spheric Continuum: jet-like

event shape variables: used independently, in a Fisher discriminant or in a Neural Network

Signal extractionSignal extraction1dim. or multidim. fit of E, mES(Mbc), shape var., PID var.cont. bkg. - modeled with a phase-space function with kinematical threshold - studied with events of sidebands in E, mES(Mbc) outside the signal region off-resonance data, MC etc.

other B decays – decay angles, helicity angles etc.

exploit production at threshold and small energy released in

Babar, Belle, Cleo Babar, Belle, Cleo BBSee )4(

Liliana Teodorescu6

2 July 2004

HFAG – Heavy Flavor Averaging Grouphttp://www.slac.stanford.edu/xorg/hfag

In this talk used HFAG averages rely on HFAG references referenced explicitly only new results

Presented in this talkPresented in this talk

**

*

,,

),,',)(,,',(

,

),,,)(',(

,,

KKB

B

KB

KKB

KKKB

Liliana Teodorescu7

2 July 2004

Physics interestPhysics interest provide information used in CKM angles (2) and (3)

determination extraction of angles suffers from hadronic uncertainties in the theoretical calculations BFs give limits of these hadronic uncertainties ACP used to establish the direct CP violation in SM

or indicate New Physics

Liliana Teodorescu8

2 July 2004

B ->+-

B ->00 contributions from color-suppressed tree and gluonic penguin amplitudes theoretical predictions: BF < 1·10-6

observation of significant signal

B ->+0

b->u tree dominated

b->u tree dominated

+- 78fb-182fb-1

15fb-1

142fb-1 3.4

BF (10-6)

signal

140fb-1 4.2

Liliana Teodorescu9

2 July 2004

BF’s ratios expectations significant penguin contributionto +- mode => penguin pollution complicates the extraction of (2)from time-dependent CP asymmetries

CP Asymmetries

82fb-1

Preliminary

140fb-1

Direct CP violation in B0 -> + -

140fb-1

(in time-dependent analysis)

Cross check time-integrated asymmetry

PRL, hep-ex/0401029Do not observe CP violation

(time-dependent analysis)

Obsevation

PR D65,013004, 2002

Liliana Teodorescu10

2 July 2004

B ->K+ b->u tree and b->s penguin transitions penguin amplitude dominates

B ->K0+ no b->u transition, only b->s penguin trans. good case to determine penguin’s contrib.

B ->K00 dominated by color suppressed tree

82fb-1

82fb-1 78fb-1 15fb-1

Significant penguin contribution

isospin relations the 3 ratios = 1

BF(10-6)


2 July 2004

CP AsymmetriesB ->K could be significant due to interference between T and P amplitudes

no evidence of direct CP violation in K decay modes

B ->KK BFs give information about the rescattering processes (FSI) rescattering can modify BF and ACP for and K modes KK more sensitive to rescattering effects

BF limits in agreement with pQCD predictions (PR D63, 014003 (2000)) no evidence of rescattering yet

82fb-1

Preliminary

9.13fb-1

140fb-1

BF (10-6)


2 July 2004

Physics interestPhysics interest

provide information for understanding the relative contribution

of tree and penguin amplitudes in B decays

have potential for establishing the direct CP violation


2 July 2004

CKM suppressed

destructive interference and /’ mixing

)()'( KBBFKBBF

)'()( ** KBBFKBBF

ACP expected (20-40)%

for the suppressed modes

flavor-singlet (important for ´K*)

Belle: -0.020.070.01Cleo: +0.030.120.02

PL B254(1991)247

BF (10-6) K0, K*0 modes - no external tree

agreement with NLO QCDNP B651(2003)225

Preliminary


2 July 2004

color suppressed

dominant

CKM suppressed

0, 0 modes - no external treeBF (10-6)

Expectations: BF’s: (0.1-1.0) 10-6 ((’)+ the highest)

ACP: large for , small for

ACP

hep-ph/0307395

Preliminary


2 July 2004

Physics interest

provide methods for extracting CKM angle ( 2 )

e.g. decay amplitude isospin analysis of

decay amplitudes are extracted from BFs and ACP asymmetries

test the theoretical models with the BF’s ratio

(large range of predictions)

0000 ,,,B


2 July 2004

needed for the isospin analysis for extractionusing the decay modes:

give limits on the contribution of penguin ampl. BF predictions around or below 10-6

0000 ,,,B

00Bhep-ex/0405068

140fb-1

Nsig=15.14.8Sig. = 3.5

BF=(5.11.60.9)·10-6

82fb-1 BF < 2.9·10-6

00B 00B

Evidence

signalcont. bkg.

cont.+ B bkg.

BF higher than the theoretical predictions central value higher than BaBar limit

Some contributions to the decay ampl. higher than expected => isospin analysis more complicated


2 July 2004

BF (10-6)

)(

)(0

0

BBF

BBFR

BF’s ratio Theory R 6 tree level estimates Z. Phys. C34, 103 (1987) R 2-3 penguin, off-shell B*

Excited states, scalar +- resonan.PRL 86,216 (2001), PR D66,034019(2002)

Babar

24.037.020.031.038.2

R

Acp no evidence of direct CP violation

82fb-1 140 / 78fb-1 9.1fb-1


2 July 2004

suppressed amplitudes => BF ~ 10-6 or even less (e.g. BF(B->)~10-9)

Physics interestPhysics interest test of theoretical models – many different approaches search for New Physics signature

PRD 68, 015004 (2003)

model independent bound on sKss KSKSS )()(

S: time–dependent CP asymmetry parametercalculated with BF’s of

00000 ,,,,,, K

If the experimental S much higher than this bound => New Physics


2 July 2004

Sign. Babar 82fb-1 Cleo 3.1fb-1

hep-ex/0403046Submited to PRL

BB0 0 -> ->

0

0

17.0 sKWith the new BF values:

Scharmonium= 0.7360.049S’Ks

= 0.270.21

HFAG average


2 July 2004

angular distribution reflects strong and weak interaction dynamics

aditional observables for detecting direct CP violation or NP

fL=L/ - longitudinal polarization fraction

Physics interestPhysics interest

modes provides an alternative method for measurement


2 July 2004

B->B->KK** - pure b->s P(unambiguous signiture for P)

B->B->KK** - dominant b->s P+ b->u tree B->B-> - b->u Tree and CKM suppressed b->d P(potential measurement)

0B

1.5.988 23

21

SigN

AACP CP expectationsexpectationsK* : 1% in SM, <30% with NP contributionK *: possible large (T–P interf.)+0: isospin-breaking processes(e.g. EW P)=> high CP asym.

BF (10-6)

AACPCP 82fb-1

9fb-1

78fb-1

78fb-182fb-1


2 July 2004

PolarizationTheory predictions – longitudinal polarization dominates in all modesMeasurements - helicity angular distribution analysis

- full 3-dim. angular analysis ( K*0 - Babar, Belle)

fL

As expected

As expected

Less than expected!!

B->K* NP in b->s penguin transition? (hep-ph/0310229)

82fb-1 78fb-1


2 July 2004

observation of B->00 BF = (1.90.5) 10-6 (HFAG)

observation of direct CP violation in B-> +- (Belle)

no other evidence of direct CP violation time-integrated CP asymmetries (Babar)

need more data to establish a conclusion evidence for B->00 , Sig. 3.5 (Belle)

BF higher than theoretical predictions

(Babar)

B-> fL 1 expected (Babar and Belle) B->K* fL<<1 not expected (Babar and Belle)

time-integrated

17.0)()( sKss KSKSS

B factories are living interesting times. More interesting ones will come!

rare hadronic b decays

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