Results from B-factories

ByungGu CheonSungkyunkwan University

Presented at ACFA LC workshop (15-17 Dec 2003, TIFR, Mumbai, India)

outline

Belle and BaBar CP violation in B meson decays New Physics search in B factory Toward >1035 lumonosity era

Most of physics results shown today are based on LP03 presentations !

Luminosity frontier colliders

Records by summer 2003,now data taking again!

Detectors

• Typical design : SVD+CDC+PID+ECL+KLM

• PID : TOF+ACC vs DIRC

Belle BaBar

Time-dependent CP violation

0B

0B

CPfM-2ie f

0 0q = 1 = ( ) for tag-side B B

If either S or A is non-zero, B fCP has CP asymmetry.If either S or A is non-zero, B fCP has CP asymmetry.

CP( ; ) = 1+ q A cos( ) + S sin( )

| t|

4

B- D / t

d dm m

eB f t t t

Bt

Mixing-induced CPV param.

Direct CPV param.

CP eigenstates

category CP mode process CP(f) SM prediction

S A Penguin

charmonium J/ KS f sin21

0 negligible

(2S) KS

C1 KS

C KS

J/ K*(KS0)

J/ KL

charmonium J/ 0 f sin21eff yes

double charm

D(*)D(*) small yes

bs penguin

KS f sin21

small dominant

’ KS

K+KKS

hh f sin22eff yes

b ccs

b ccd

b uud

b sqq

(f CP eigenvalue)

0

0

e e+e: 8.0 GeVe+: 3.5 GeV

BCP

z

Btag

(4S) ~ 0.425

fCPfCP

z cB ~ 200 m

Flavor tagFlavor tag cz t

bg ¡

D D;( )c

z tbg ¡

D D;( )

4 steps toward the CP violation measurement

• Reconstruct B fCP decays

• Determine the flavor of Btag

• Measure proper-time interval : t • Evaluate asymmetry from the obtained t

distributions

How to measure CP violation?

B0 (cc)KS vs. (ss)KS

68 signals

BB140 fb ~152M pairs- 12716 signals

tags)(poor

tags) (good

DCPV No 0.0411.007 ||

0.0280.0570.733sin2

scc

1

06.073.02sin 1

13.080.02sin 1

0.0490.736)2WA2003(sin

tmeasuremen precision a becoming Now

1

sin21 : bbccsccs

Theoretically cleanest example :

sample control

sample signal

sin21 : bbssssss

First Indication of New Physics in quark sector

A

S = 0.96 0.50

= 0.15 0.29 0.07

+0.09- 0.11

-

-

fS 1 = sin2 eff

Summary of sin21

NP? Stat. Fluctuation?more data: interesting

2003 2006

Sbs: 3.1 away from Sbc

2.1difference in Sbs(Ks)

2.1

Sbs

Sbc

New Physics search in B decays

Tree diagrams: New Physics(SUSY) effect ~negligible Loop diagrams: W, heavy quark loop in the SM Effect of NP particles in loop can be visible

Processes with loop diagrams only sensitive to NP

squark

b s

squarkb

b

d

d

Penguin

Box

Aobs = ASM + ANP

deviation from ASM only

|Aobs| Branching fraction phase(ASM/ANP) CP asymm.

Many modes/ways in B-factory !

B/ decays for NP search

• New CPV phase in Penguin : Time-dependent CPV

• Radiative & EW Penguin : b s, b sll

• LFV decays :

• DCPV in K-cK interference(b s Penguin)

• b s, B l, ll , B D(*)

• NP in B0-mixing by detailed () consistency study

• and so on…

B K*(892) 78fb-1

B(B0K*0) = (4.09 0.21 0.19)B(B+K*+) = (4.40 0.33 0.24) x10-5Isospin asymmetry: 0+ = []/[+] = +0.003 0.045 0.018[SM: 0+ >0 sign of Re(C6/C7)]

CP = -0.001 0.044 0.008(SM: |CP| < 1%)

decay throughPenguin only

sensitive to NP !

b ds,

tcu ,,NP particles?!

BXss

No deviation from the SMNeed reducing errors: theory : NLO to NNLO exp. : lower E (more data)

All measurements agree.Need better theor. precision: debate on BK* form facor

Inclusive

Exclusive

b s

b s l+l-

Penguin + Box diagram contributionAdditional dimension: Mass(l+l-) [l+l- angle helicity]

More opportunity to distinguish New Physics effect/models

BKl+l- : first observed by Belle @29fb-1 (LP 2001) BK*l+l- : first evidence by BaBar @81fb-1 (EPS03) Now Belle/BaBar updated with 140fb-1/113fb-1 data !

(exclusive)

B Xsl+l-

6

6

6

10)4.11.14.11.6(

10)1.25.11.29.7(

10)3.11.13.20.5(

lXslBBF

XsBBF

eXseBBF

60 fb-1

Semi-inclusive analysis (pseudo-reconstruction)

Xs=(K+ or Ks)+0~4(0,1 ) (covers 81%)MXs<2.1 GeV/c2

[PRL 90, 021801 (2003)]Inclusive bs l+l- : better theoretical prediction

60.1 13.9 ev.5.4

hep-ex/0306018(BaBar) w/ 81fb-1

Mll and MXs distributions

Mass distributionSM prediction

observed Mll

spectrum

Model by A.Ali et al.

M l l (GeV/c2) M(Xs) (GeV/c2)

observed M(Xs) spectrum

~ consistent with SM prediction

[PRD 66, 034002(2002)]

SM acceptance corrected

b s l+l-

[A.Ali, et al. PRD 64, 074024(2000)]

K*

BF

K*

Afb

More datatowardsSUSY

M

M

Started tosee signals(consistent with SM)

Rare B decays

If we’ve more data…

decays

B-factory : also excellent -factory

Promising mode to see New Physics effect

decayforbidden in the SM (very small even with mixing)

SUSY, L-R symmetry model … allow LFV decays

Br() ~

[~ xBr(e)]

SUSY particles

(~1M -pairs/fb-1)

Search for Reconstruction E = E +E-Ebeam

Minv = Mass()2D unbin’d extendedMax. Likelihood fit

Result ： s<5.1 @90%CL

Br( )< 3.1x10-7 @90%CL

Signal MC

sideband

(78.5M -pairs)

region sel= 0.11)

CM CM CM

hep-ex/0310029

(New)

The mystery meson

evt2

2

N = 35.7 6.8

M = 3872.0 0.6 0.5 MeV/c

= 1.4 0.7 MeV/c

0 *0D D

Unaccountable to any unestablished charmonium states.

Observed mass is higher than QCD model predictions.

Observed X(3872) mass is equal to nearly DD* threshold mass.

M = 3871.3 0.5 MeV/c

2

A possibility of loosely bound DD* molecular state ?

Interpretations of the mass is complicated by the DD* threshold.

To appear in PRL & hep-ex/0309032

KEK B-factory upgrade strategy

Present KEKB L=1034

2002 03 04 05 080706 09 10 11

L=2x1035

L~1036

∫Ldt =350fb-1ILER=1.5A

ILER=9.4A

ILER=20AConstraint: 8GeV x 3.5GeV wall plug pwr.<100MW crossing angle<30mrad

L=2x1034

ILER=1.5A

Crab crossing

One year shutdown to:install ante chamberincrease RFmodify IR

Increase RF

1999-2003 data set (158fb-1) in 1 week

L=5 1035 (New)

• Optimal scenario: NP found at Tevatron/LHC/LC– Super-B to measure its parameters(flavor mixing, CPV,…) p

recisely. If NP is SUSY, the interest is in its breaking mechanism. Even if no deviation from SM is found, that is very interesting. (No effect of existing particles?)

• Intriguing scenario: deviation from SM found in flavor physics (has already started?)– Super-B to measure it more precisely.

• Frustrating scenario: SM looks fine even after LHC/LC– Super-B to search for NP, competing with LHC/LC.

Some words on Super-B projectHL05 workshop @Izu

Super B Factory Workshop in HawaiiSuper B Factory Workshop in Hawaii

January 19-22, 2004East-west Center, Honolulu

To discuss physics, accelerator and detector

assuming NBB, N>1billion, L>1035.

Comparsion with the previous results

Belle

BaBar

?

K

K c.m.s

New possibility to measure helicity or CPV (more sensitive to NP than Br)

SM: ~left-handed ~ no Time-dependent CPV

Helicity : B Xs , Xs 3-body [K1(1400) K]

SUSY,LR-symm.: right-handed Sizable CPV

CPV: B0 K1(1270)

KsKs

[M.Gronau et al., PRL, 88, 5(2002)]

[D.Atwood et al., PRL, 79, 185(1997)]

B K∫L dt = 29 fb-1

[PRL 89, 231801(2002)]

B(B+K++-) = (24 5 )x10-6+4

2

A big step towards -helicity meas., Time-dep CPV !

First Observation !

Bump : MK=1.3~1.4 GeV

K*(892), peaks seen

Need more data to extract K1(1270),K1(1400)

Search for

Signature(topology): [signal side]

+ opposite sign track (not ) (+ ’s) [tag side]

pmiss > 0.4GeV()

Mmiss ~ 0

tag