23, June, 2005 Beauty2005, Assisi, Italy

Electroweak Penguin decays at Belle

Akimasa Ishikawa

KEK

Flavor Changing Neutral Current Decays

Flavor Changing Neutral Current decays, bs, bsll Forbidden at tree level induced through Penguin or Box diagrams at lowest order sensitive to heavy particles (SUSY, heavy Higgs)

Observables Decay Width (Branching Fraction)

Inclusive decay, theoretically clean, experimentally hard. Exclusive decays, large uncertainty due to form factor

test of QCD in B decays

Ratio of Decay Width Some theoretical and experimental uncertainties cancel Good probe also for exclusive decays!

CP Asymmetry Isospin Asymmetry Up-Down Asymmetry BF ratio of electron mode to muon mode Forward-Backward Asymmetry

Penguin diagram in the SM

Beyond the SM diagram

OPE and Wilson Coefficient

Effective Hamiltonian is expressed in term of Operator Product Expansion.

O1,2: current current operator O3-6 : QCD penguin operator O7,8 : electro- and chromo-magnetic operator O9,10 : semileptonic operator Ci : Wilson coefficient

Wilson coefficient is a strength of corresponding short distance operator.

Precise measurement of Wilson coefficients is one of the goals for B physics.

For bs and bll case, only O7, O9 and O10 appear in the Hamiltonian.

New Physics changes the Wilson Coefficients

bs and bsll decays

eff eff eff eff eff *9 10 7 7 9

22 5 *22

3

2 2 2

ˆ1ˆ 4 48

2ˆ1 2 4 1 12Re

ˆ

F b ts tbem

C

d b s G m V Vs

ds

s C C Cs

C

22 5 *

2

3eff732

F em b ts tbG m Vs C

Vb

can be extracted from B(bs), B(bsll) and AFB (bsll) !7 9 10, andeff eff effC C C

Decay widths for bs and bsll can be described with Wilson coefficients.

Absolute value of can be measured.

7effC

Interference terms

(sometimes we do not use Ci but Ai which is leading coefficient)

Relative signs can be also determined from interference terms!!

In the SM

Branching Fraction of BK*

bs was observed at CLEO in K* K* is reconstructed from 4 modes

K+-, Ks0, K+0 , Ks+

|MK* MK| < 75MeV

Better than 10% accurary! Theoretical preduction

QCD fact. (70 25) 10-6

LEET (68 23) 10-6

pQCD (35 10) 10-6

Lattice (35 16) 10-6

B(B0 K*0) = (40.9 2.1 1.9) 10-6

B(B+ K*+) = (44.0 3.3 2.4) 10-6

Theoretical uncertainties are large 80/fb data

K*

K2*(1430)

Asymmetry in BK*

Isospin Asymmetry 0+ is sensitive to sign of Wilson coefficients C6/C7

0+ = +5~10% and C6/C7 >0 in the SM

If C6/C7<0, 0+ <0.

Direct CPV is less than 1% in the SM 5% CPV is allowed in new physics

ACP = (-0.1 4.4 0.8)%

0+ = (+3.4 4.4(stat) 2.6(syst) 2.5(f+-/f00))%

)(B)(B

)(B)(B**00

**00

0

0

0

KBKB

KBKB

B

B

B

B

B0 B0

A.Kagan and M.Neubert, PLB 539, 227 (2002)

Time dependent CPV in BKs0

Not only the K*0, but any Ks0 can be used for TCPV measurement.

In the SM, S<0.1, A<0.01. Right handed currents induce large value of S

S corresponds to fraction of C7R to C7L

MKs < 1.8GeV

tmAtmS

KtBKtB

KtBKtBA

SS

SSCP

cossin

)()(

)()(000

000

0000

00

)(11.0)(38.0

46.058.0)( 00 syststatKS S

)(11.0)(34.003.0)( 00 syststatKA S

250/fb data

K* K2*(1430)

Atwood, Gershon, Hazumi, Soni PRD71 (2005) 076003

First Measurement

Observation of BK

Ks can be used for time dep. CPV measurement to search for right handed currents.

BK+, Ks is reconstructed from and 0

MK < 2.4GeV

6

9.0

2.1 105.14.8)(B

KB

6

6.1

9.1

7.2

1.300 104.8)(B

SKB

First Observation

250/fb data

%6916)(A KBCP

B0 B0

Observation of BK1(1270)

BK final state via K1 can be used for up-down Asymmetry to search for right handed currents. K1(1270) is reconstructed from K++- and Ks+-.

0.6< M < 0.9GeV ( mass region) to enhance K1(1270) Resonance components are extracted by fitting to the hadronic mass

distribution. First Observation 5

1 109.09.03.4))1270((B KB

51 105.1))1400((B KB

140/fb data

501

0 108.5))1270((B KB

M.Gronau et al. PRL88 051802 (2002)

Observation of Bp

Baryon production via weak decay of meson

Near threshold enhancement of di-baryon system is observed in Bp (bs process)

Near threshold enhancement also observed Fragmentation?

First Observation

6

53.0

58.0 1020.016.2)(B

pB

140/fb data

Theoretical prediction ~10-6

Inclusive BXs

Full inclusive b Photon with E>1.8GeV Veto photons from 0 and Subtract continuum with off-resonance data Moment analysis to extract HQET paramet

er

<E> = 2.289 ± 0.026 ± 0.035 GeV

<E2> - <E>2 = 0.0311 ± 0.0073 ± 0.0063 GeV

140/fb data

HQET parameter2

05.0

08.0 GeV/c66.0

used to extract Vcb and Vub

BF of Inclusive BXs

Subtract bd assuming B(bd)/B(bs) = 3.8 ± 0.6%

Measured BF is consistent with theoretical predictions. MH+ >200GeV 95%CL (M.Neubert CKM2005)

Limit on Wilson coefficient A7 -0.36 < A7 < -0.17 or 0.21< A7 < 0.42 In the SM A7 = -0.33 at = 2.5GeV

410))(07.0

11.0)(

31.0

30.0)(32.059.3()(B

theosyststatXB s

G.Hiller and F.Krueger

PRD 69 (2004) 074020

Exclusive BXs / Inclusive bs

40% of bs are measured exclusively. Next step : B0K0S0for TCPV analysis.

K’, Kf0, Ka0…..

K*

K1(1270)

K2*(1420)

K*

KK

Kp

59 ±6.0% missing

Isospin symmetry for B and K* decay is assumed

Search for B

bd process has not been observed Simultaneous fit to B--, B00 and B0

From isospin relations:

constrain |Vtd/Vts|

B(B- -) = 2 ((B-)/(B0)) B(B0 0) = 2 ((B-)/(B0)) B(B0 )

B(B(,)) = B(B-) < 1.4 10-6

250/fb data

SM predictions: B(B--) = (0.90 ± 0.34) 10-6 (Ali-Parkhomenko) B(B--) = (1.50 ± 0.50) 10-6 (Bosch-Buchalla)

Rmm

mm

V

V

KB

B

BK

B

ts

td

1

)/1(

)/1(

)(B

)),((B 2322

322),(

2

*2

22.0ts

td

V

V

R : form factor ratio

: SU(3) breaking effect

Just above the SM prediction!!

Inclusive BXsll

Semi-inclusive technique Electron or muon pair

Mll>0.2GeV Charmonium veto

Xs is reconstructed from K+ or Ks + 0-4 (at most one 0 is allowed) MXs < 2.0 GeV

140/fb data

687.083.0 1030.104.4)(B

eeXB s

685.081.0 1005.113.4)(B

sXB

685.081.0 1083.011.4)(B

sXB

61070.02.4)(B sXB

Theoretical preduction by Ali et al.

Wrong flavor

MXs q2

Limit on Wilson Coefficients

Clean prediction of BF of B(BXsll) for 1<q2<6GeV2 is available. Combine Belle and Babar results Sign of C7 flipped case with SM C9 and C10 value is unlikely.

P.Gambino, U.Haisch and M.Misiak PRL 94 061803 (2005)

BF Belle Babar WA SM C7 = -C7SM

q2>(2m)2 4.11±1.1 5.6±2.0 4.5±1.0 4.4±0.7 8.8±0.7

1<q2<6GeV2 1.5±0.6 1.8±0.9 1.60±0.5 1.57±0.16 3.30±0.25

C7SM C7 = -C7

SM

C10NP C10

NP

C9NP

MXsq2

Branching Fraction of BK(*) ll

K+, Ks or K*(K+-, Ks+, K+0) + e+e- or +-

Mll>0.14GeV

A ratio of BF of K(*) to K(*)ee is sensitive to neutral heavy Higgs in 2HDM with large tan. In the SM, the ratio is 1.00 and ~0.75 for Kll and K*ll

250/fb data

Prediction by Ali et al.

Y. Wang and D. Atwood PRD68 (2003) 094016

G.Hiller and F.Krueger PRD 69 (2004) 074020

First look at AFB in K*ll

Sign of C7C10 can be determined from Forward-Backward Asymmetry in K*ll.

Raw AFB in each q2 region is extracted from Mbc fit. Kll has no asymmetry, so it is a good control sample. Curves show theoretical distributions including expe

rimental efficiency effect (not fitted lines! ). Both curves are in agreement with data, so far.

AFB K* l l

Ali et al. Phys.Rev. D61 (2000) 074024

SM

7 7eff eff

SMC Cq2

Summary

Many results for BF are consistent with the SM Precision of BF(bs) is 15% level.

Negative A7 solution is consistent with the SM A7 value

Upper limit on B(B()) is just above the predictions Constrain |Vtd/Vts|

Improved measurement of inclusive BXsll decay Sign of C7 flipped case with SM C9 and C10 values is unlikely

stringent limits on C9 and C10

Many measurements of Ratio Precisions of 0+ (BK* ) are 5% level

Towards sign of (C6/C7).

Time dep. CPV in BKs0 is measured for the first time Search for right handed component in C7

First look at Forward-Backward Asymmetry in BK*ll Will be used for measurement of A9 and A10

New results will be presented at Lepton Photon 05. Stay tuned

Backup Slides

AFB at Super Belle

1 year running at 5x1035/nb/sec 5/ab integrated luminosity, 10 billion B mesons!!

We have accumulated ~0.46/ab, about x10

A9/A9~11%, A10/A10~13% A7 fixed to SM value systematic error is not included

Belle Toy MC with 5/abC10

NP

C9NP

Donut : B(BXsll) with140/fb

AFB K*ll with 5/ab