Recent Results from Belle

Aug.20, 2004 Recent results from Belle 1

Recent Results from Belle

Shiro Suzuki 　　 (Saga University)

PASCOS04 / Pran Nath Fest, Aug 20, 2004 　　　　　 Northeastern University, Boston, MA


Outline

Belle / KEKB

CPV “Standard” sin21 as the SM reference TCPV in b s penguin dominated decays Direct CPV

Rare processes FCNC ( b s, sll) via EW penguin


~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

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

28 fb-1 below Y(4S)

KEKB Collider


IHEP, Moscow IHEP, ViennaITEPKanagawa U.KEKKorea U.Krakow Inst. of Nucl. Phys.Kyoto U. Kyungpook Nat’l U. U. of Lausanne U. of Ljubljana Jozef Stefan Inst.U. of Maribor

Aomori U.BINPChiba U.Chonnam Nat’l U.Chuo U.U. of CincinnatiEwha Womans U.Frankfurt U.Gyeongsang Nat’l U.U. of HawaiiHiroshima Tech.IHEP, Beijing

U. of MelbourneNagoya U.Nara Women’s U.National Central U.Nat’l Kaoshiung Normal U.Nat’l Lien-Ho Inst. of Tech.Nat’l Taiwan U.Nihon Dental CollegeNiigata U.Osaka U.Osaka City U.Panjab U.Peking U.Princeton U.RikenSaga U.USTC

Seoul National U.Shinshu U.Sungkyunkwan U.U. of SydneyTata InstituteToho U.Tohoku U.Tohuku Gakuin U.U. of TokyoTokyo Inst. of Tech.Tokyo Metropolitan U.Tokyo U. of A and T.Toyama Nat’l CollegeU. of TsukubaUtkal U.VPIYonsei U.

13 countries, institutes, 400 members

The Belle Collaboration


/ 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

Belle Detector


b

s

d

VVV

VVV

VVV

b

s

d

tbtstd

cbcscd

ubusud

'

'

'

2

2

)1(

2/

)(2/

AiA

A

iA

CPV: due to a complex phase in the quark mixing matrix

CKM matrix

Wolfenstein representation

1

2

3

Vtd Vtb

Vcd Vcb

Vud Vub*

*

*

Unitaritytriangle

Kobayashi-Maskawa Scheme

observablesWeak eigenstate

Mass eigenstate


Time dependent CP Violation (TCPV)

For single decay diagram as above,

||=1 (i.e. A=0, no DCPV), S = Im 1

2

, sinSimil

si2

a

n

r ,

2

ly

bb ccd

uudsqq

1ex) sin 2 fSb ccs

General description

2

2

0

02

2I

1=

m

1

1 CP d

f

CP d

f Bq

p f BS A

whereMixing induced CPV

Direct CPV0 0

0 0

( ) ( ) sin( ) cos( )

( ) ( )d CP d CP

CPd CP d CP

B f B fA m t m t

B f B fS A


5417 events @ 140 fb1

sin21=0.7280.0560.023

ccs1.007 ± 0.041 ±

consistent with no direct CPV

Good Tag

Poor Tag

Good agreement with SM SM Reference

sin21 by b →ccs processes

now issue is to measure “sin21” with different decay processes such as ccd, sqq .

WA = 0.736±0.049


CP Violation in penguin dominated decays

SM Penguin : same CPV phase as ccs

+ New Physics with different phase

+

CPV may be different : Sbs≠Sbc, A≠0 ⇒

hint of new physics Ex) B0 Ks 7.8 1.1 (×106)* theoretically clean but Br small B0 ’Ks 65.2 6.0 　 B0 K+KKs 25.2 2.7

b→sqq: Possible contribution of new physics → new phase


Fit sin21

B0 KS B0 KKKSB0 ’KS

fS

A

09.011.050.096.0

07.029.015.0

18.000.005.026.051.0

04.016.017.0

05.027.043.0

04.016.001.0

[PRL 91, 261602 (2003)]

“sin21” 3.5 away from SM !

=b→s modes in 2003

⇒ Needs measurements w/ larger data sample & additional modes

140fb


Validity checks of 250fb-1 sample SM control sample : J/K0

Data set I (140fb) S = 0.696±0.061 A = 0.011±0.043

Data set II (110fb) S = 0.630±0.069 A = 0.035±0.044

Life time in J/K0, K+, K0 Null asymmetry in D*l , K+

⇒ overall check of resol. func. & flavor tagging

Data set I

Data set II

Good tags

Good tags


B → K0

includes Ks (Nsig=13 5)

pB*

274M BB

KS

Nsig=139 14purity 0.63

Nsig= 36 15

KL

purity 0.17


B → K0 　 CPV result

KS + KL

: S (K0) = +0.06 ±0.33 ±0.09

A (K0) = +0.08 ±0.22 ±0.09 “sin21” ~2.2 away from SM

KS + KL

: S (K0) = +0.06 ±0.33 ±0.09

A (K0) = +0.08 ±0.22 ±0.09 “sin21” ~2.2 away from SM

274M BB

Poor tags

Good tags

preliminary

S = 0.736fit


’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

0.170.00

B0 → ’KS & K+KKS

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

high statistics modes’

( , )


KS

New modes !

Nsig=31 7purity 0.56 Nsig=102 18

purity 0.58

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 tags

B0 → KS & f0(980)KS

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


Summary of b→sqq TCPV

A : consistent with 0

2.4

“sin2”


Direct CPV in B →K

Another essence of KM scheme – existence of direct CPV More than two diagrams should contribute

-- With different CP and strong phase

CPV in decay – partial rate asymmetry

( ) ( )

( ) ( )CP

N B f N B f

N B fA

N B f

Penguin d

b

d

u

uW

B0d -

Vus

Vub

Tree

B0dd d

u

u

W

g

-

VtsVtb

ts

s

b


Evidence for direct CPV in B0→K+

Signal yield: 2139±53

ACP (K) 0.101±0.025±0.005 ( 3.9 significance )

2nd evidence ofDCPV at Belle

Continuum BG elimi-nated by modified F-W

K/ ID efficiency and fake rates determined by D*+→D0, 　 D0→K sample

_B0 K B0 K

274M BB

Submitted to PRL


ACP for B+→K+

Hint of ACP(K+)≠ACP(K+0) 2.4 away

Large EW penguin contribution ? New physics ?

K+ Signal yield : 728±34 ACP(K+

0.04±0.05±0.02

B

K

274M BB, New


Observation of B0 00Observation of B0 00274M BB, New

B = (2.32 ) x 10-6 Signal: 82 16 (6.0)

ACP = 0.43 0.51

uses same Flavor-tagging as TCPV analysis

1st measurement !

Mbc

0.410.48

0.220.18

0.170.16

Key mode for 2 in B→ CPV isospin analysis


Radiative and EW Penguins

Br(b→s) ≈ 3.5×10

Br(b→sl+l≈ em×Br(b→s) ≈ 10

New particle (via loops) may make appreciable contribution to decay rates and/or asymmetries.

Good testing ground of

SM and beyond SM.

b→s, sl+l decays proceed via FCNC Box and penguin diagrams

b→s

b→sl+l


B→ K(*)l+l results274M BB

Updated with 274M BB

Preliminary

79 10signals

82 11signals

0.75 70.70

*

2.3 72.2

( )

(5.50 0.27 0.02) 10 (11.0 )

( )

(16.5 0.9 0.4) 10 (10.1 )

B Kl l

B K l l

B

B


( / 2) ( / 2)

( / 2) ( / 2)Bl Bl

FB

Bl Bl

A

AFB in K*ll provides information on sign of Wilson coef. ⇒ sensitive to NP that may not be seen in bs

PreliminaryFirst look !

K*

B→ K(*)l+l FB Asymmetry


SummaryBased on 253 fb data sample TCPV of b → s penguin processes are measured in va

rious processes. Updated “sin21” in K0 is +0.06 ±0.33 ±0.09

~2.2 away from SM b→s average ： +0.43 ± ~2.4 away from SM.

Evidence of DCPV in B0→K+ is observed Hint of ACP(K) ≠ACP(K)

First look at B K*ll AFB is made.

0.130.11

Recent Results from Belle

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