rare b decays at belle hsuan-cheng huang ( 黃宣誠 ) national taiwan university 2 nd bcp workshop...

Rare B Decays at Belle

Hsuan-Cheng Huang (黃宣誠 )National Taiwan University

2nd BCP Workshop @ NTU, TaipeiJune 7 - 9, 2002

7-J un-2002 BCP2 Workshop Hsuan-Cheng Huang

Rare B Meson Decays at Belle (p.2)

Outline Introduction Charmless Hadronic B Decays Charmless Baryonic B Decays Radiative / EW Penguin B

Decays Suppressed b -> c Decays Summary



Introduction Rare B decays can be described by various

tree and penguin diagrams They are useful to determine the CKM

unitarity triangle Search for CP violation and probe new physics



Belle Collaboration

A World-Wide Activity Involving 50 Institutions

14 Nations



Belle Collaboration ~ 300 authors



KEK View 日本　茨城県　つくば市



8GeV electron 3.5GeV positron

(4s) (10.58GeV/c2) = 0.425(4s) B B

KEKB Collider

KEKB Asymmetric e+e- Collider



KEKB Luminosity: the world’s best !

Peak L 7.251033 cm-2s-1 (Mar. 28, ’02)Daily Integrated L 387 pb-1/day (May 11, ’02)Weekly Integrated L 2.52 fb-1/week (May 9, ’02)

Peak L 7.251033 cm-2s-1 (Mar. 28, ’02)Daily Integrated L 387 pb-1/day (May 11, ’02)Weekly Integrated L 2.52 fb-1/week (May 9, ’02)

82 fb-1

recorded(Jun. 6, ’02)

82 fb-1

recorded(Jun. 6, ’02)

Daily Integrated luminosity history

Integrated luminosity history

43 fb-129 fb-1



Silicon Vertex Detector (SVD) Impact parameter resolution 55m for p=1GeV/c at normal

incidenceCentral Drift Chamber (CDC) (Pt/Pt)2 = (0.0019Pt)2 + (0.0034)2

Pt in GeV/c2K/ separation with dE/dx in CDC (dE/dx =6.9%) TOF (TOF = 95ps) Aerogel Cerenkov (ACC) Efficiency = ~87%, Fake rate = ~8% up to 3.5GeV/c, e with CsI crystals (ECL) E/E ~ 1.8% @ E=1GeV e : efficiency > 90% (~0.3% fake for p > 1GeV/c)KL and with KLM (RPC chambers) : efficiency > 90% (~2% fake at p > 1GeV/c)

Quite stable performance up to now

ACC

Kaon efficiency contamination

87%

8%

PID(K)>0.6

Belle Detector



Signals

Analysis Method Identify Signals: beam-constrained mass Mbc and energy difference E

7-J un-2002 NTHU Seminar Hsuan-Cheng Huang


B hh: Introduction



K+- K+0 K0+ K00

+- +0 00

B hh: Results Updated measurements with 31.7M BB

mass is assigned to charged tracks Likelihood ratio cut optimized for each mode Shaded area corresponds to background from other rare B

decays ⇒ Better fitting systematics 00 Hint ⇒ Feedback to 2 measurement

Prelim

inary

29 fb-1



B hh: Branching Fractions

00 Hint No KK yet! Pre

liminary

BaBar 55.6 fb-

1

*

*

* 20.6 fb-1

Bartoldus @ FPCP



B hh: Direct CP Search

Prelim

inary

K+-

K-+

K+0

K-0

+0

-0

K0-

K0+

bb quark

Fluctuation?

BaBar 55.6 fb-1



B (‘)h: Introduction



Results of B K* / ’K

98

29 fb-1



B K Results

Prelim

inary



B Results

Prelim

inary



B (‘) h: Summary

Prelim

inary



B h: Introduction



B h: Results

Prelim

inary

0

0 M



B h: Consistency Check



B h: Summary

Prelim

inary



B Khh Dalitz

Sizable

PRD 65 092005 (2002)

Three-Body Charmless B Decays

First Observations of



B -> K h h’

A. Garmash @ FPCP* PRD 65 092005 (2002)** H.C.Huang@Moriond 02 EW

Prelim

inary



Pseudo-Two-Body Decay BFsB+ K+ + -

B+ K+ K+ K-

B+ KS K+ K-

B+ KS + -

PRD 65 092005 (2002)

Prelim

inary

29 fb-1

43 fb-1

Gabyshev @ DPF2002



Charmless B Decays to Baryons

PRD 65, 091103 R (2002)



First Observation of Charmless Baryonic B Decays



3-body Baryonic B Decays, cont.

Chua, Hou, Tsaihep-ph/0204186

fJ(2220)?

Chua,

Hou & Soni, PRL 86, 4247 (2001)

J/

7-J un-2002 BCP Workshop Hsuan-Cheng Huang


EM

Starting to Constrain NP

Radiative B Decays

Prelim

inary

)892(*KB

PRL 88, 101805 (2002)

BaBar(20.6 fb-1)



UL

PLB’01

More Radiative Penguins

45M

BB

B

Exclusive (K, K) / Inclusive = (35 ± 8) %

hep-ex/0205025, submitted to PRL



Signa

l !

First Obseervation of ElectroWeak Penguin !?

.B K Observation

PRL 88 021801 (2002)

But, BaBar 20.7 fb-1

6* 105.3)( KBB

610.030.018.024.0 10)84.0()(

KBB

FPCP 56.4 fb-1



Inclusive B -> Xsl+l-

Xs = (K+ or KS) + (0 ~ 4) + (upto 1 0)

6 6

8.0 3.97.3 3.8

7.9 5.4 2.3 1.67.4 3.8 2.1 1.7

11.0 9.6 1.6

2.6

1.410.4 8.0 1

1.32.4

1.2

1.2

.6

(5.1

( 10 ) ( 10 ) .

16.6 11.0 2.1

30.7 8.9 4.4

47.6 7.1 4

)

.8

s

s

s

X e e

X

X

Mode #Signal BF UL Signif

First Evidence!

First Evidence!

Senyo@FPCP43 fb-1

Prelim

inary



Inclusive B -> Xsl+l-

With higher statistics, more information will be obtained from M(Xs) and M(ll) distributions

J/psi and psi’ vetoes

KK*

MXs Distribution Mll Distribution

MC based on the NNLO calculationAli-Lunghi-Greub-Hiller, hep-ph/0112300



Summary Recent Rare B Results from Belle

have been presented First Observations:

B ppK±, Khh, Kll, K First Evidence: B ± , K± , Xsll “Re”-Observation: B± K±

Improved Measurement: B K, , K*

More and more interesting results are coming 80fb-1 @ ICHEP2002

rare b decays at belle hsuan-cheng huang ( 黃宣誠 ) national taiwan university 2 nd bcp workshop...

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