July 15-19, 2003 Lattice 2003, Tsukuba, Ibaraki, Japan Masashi Hazumi (KEK) 1 Masashi Hazumi (KEK)...

July 15-19, 2003 　　 Lattice 2003, Tsukuba, Ibaraki, Japan Masashi Hazumi (KEK) 1

Present and Future of KEK B factory

-- Unitarity Triangle and beyond --

Masashi Hazumi (KEK)Masashi Hazumi (KEK)for the Belle collaborationfor the Belle collaboration

2

Belle CollaborationBelle Collaboration

Aomori U.BINPChiba U.Chuo U.U. of CincinnatiFrankfurt U.Gyeongsang Nat’l U.Hiroshima Tech.IHEP, BeijingITEPKanagawa U.KEKKorea U.Krakow Inst. of Nucl. Phys.Kyoto U.Kyungpook National U.U. of LausanneJozef Stefan Inst.

U. of MariborU. 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.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.IHEP, ViennaVPIYokkaichi U.Yonsei U.

~300 collaborators from >10 countries


KEK B factory at present


Time-dependent CP violation

CP-violating quantum interference seen as sine modulation in exponential decay(Bigi-Carter-Sanda 1981) Large O(1) CP violation hadronic uncertainty very small (~1% or less) !

e e+e: 8.0 GeVe+: 3.5 GeV

BCP

z

Btag

(4S) ~ 0.425

CP eigenstateCP eigenstate

z cB ~ 200 m

Flavor tagFlavor tag tzc

Principle of the measurement

high-luminosity e+e collider with asymmetric beam energy (~108 B mesons) precise position measurement of B-meson decay vertices (z resolution~100m

seemingly a crazy idea in 1980s 2 B factories (KEK, SLAC) in operation since 1999


The KEKB Collider

KEKB Collider

design luminosity(101033cm-2s-1) achieved in May 03

• e energy, current: 8.0GeV, 1.1A• e+ energy, current: 3.5GeV, 1.5A• peak luminosity: 10.5671033cm-2s-1 • Integrated luminosity: 579pb-1/day

12.8fb-1/month

at 10 1033cm-2s-1 ~10 (4S)/sec _ ~5 B0B0 pairs/sec ~5 B+B pairs/sec

peak luminosity history (1999-2003)

parameters (achieved)

World records !


Integrated luminosity: 1999 - 2003

KEKB

PEP-II

Most of results shown today based on data by July 2002BaBar 81fb-1 ( ~88 million B pairs)Belle 78fb-1 ( ~85 million B pairs)

~108 neutral B mesons at 100fb-1

159fb-1 logged by Belle (July 1, 2003; on + off resonance)

The full data set being analyzed now.Announcement ofnew results in the new future.


The Belle detector

A big “digital camera” that we use to take ~108 beautiful pictures/year.

O(1) ps

like in a horse race ..

position info. time difference

Belle detector Silicon Vertex Detector Drift Chamber Time-of-Flight

Aerogel CherenkovCsI calorimeter KL and detector

an example


Physics at Belle

• Physics goals:• Test Kobayashi-Maskawa model of CP (overconstrain the Unitariry Triangle)• Search for new physics in various rare decays• And many more !

• Five physics groups Indirect CPDirect CP &rare B decay &

CKM(Vub,Vcb) charm

Birthname and Nickname 1 2 3

B0 J/ KS(L), (2S) KS,

c1 KS, c KS

B0 +

b ul with several approaches

_BB mixing (md)

More will come in the near future.b cl

Belle’s Contributions to Unitarity Triangle as of now


sin21 (sin2)sin21 = 0.719 0.074 0.035 PRD 66, 071102 (2002)


B0 + and 2 () PRD68, 012001 (2003)

)]}Δcos()Δsin([1{4

);(0

0|0

tmtmqτ

etfB dd

B

/τt|

CP

B

ASP

(A,S)=(0, 0) excluded at 3.4

5-5 0

Large asymmetry

2

(strong phase diff.)

first constraint on 2

78 < 2 < 152 (95.5% C.L.)

|P/T|=0.45

b

u

dW

ubVu

Treeb

u

u

gd

Penguin

~ A (direct CP violation)can be large


The difference is at 2.2 level.

A and S : Belle and BaBar


Vub: new results this week (EPS03) !

3.97

Several approaches withdifferent systematics _

BB (Xul) (D*l)use kinematicalconstraints on Xu

1) D*l tag data

signal

1)

3) b ul endpoint 3)

2)

2) b ul in selected mX-q2 region


Constraints on Unitarity Triangle

• Beautiful agreement• Strong support for KM model of CP violation

(new Vub resultsnot included)


Rare decay: Inclusive/exclusive B Xsl+l

Access to Wilson coefficients C9, C10

First observation !

6

6

6

10)4.11.14.11.6(

10)1.25.11.29.7(

10)3.11.13.20.5(

lXslBBF

XsBBF

eXseBBF


Major achievements so far

• Observation of CP violation in B meson system [PRL87, 091802 (2001)]

• Large CP violation ! sin21 with B0 J/ Ks etc.

• CP is NOT an approximate symmetry anymore

• Evidence for CP violation in B0 + [PRD68, 012001 (2003)]• Access to the 2nd angle of the Unitarity Triangle 2 (); consistent with SM

• Observation of EW-penguin process• Exclusive process B K l+l [PRL88, 052002 (2002)]• Inclusive process B Xs l+l [PRL90, 021801 (2003)]• Access to Wilson coefficients C9, C10; Branching ratios consistent with SM

• Many other first observations and more precise measurements• Vub, Vcb, md etc.• 63 papers in total as of July 17, 2003


KEK B factoryin the future


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

18

Beam-beam simulation of crab crossing Beam-beam simulation of crab crossing • Target luminosity : 1035 ~ 1036 cm-2s-1

• Number of bunches : 5000• Beam current : I(HER) = (3.5 GeV/8 GeV) x I(LER)• Weak-strong simulation

x = 0 mradx = 15 mrad

x = 0.5156x = 0.5256x = 0.5356x = 0.549

x = 0.5156

K. Ohmi et al.

1036

1035

20 A 20 A

Crab crossing is powerful scheme to achieve higher luminosity.

crab crossing

LER beam current

Lum

inos

ity


Detector upgrade

/ KL detection 14/15 lyr. RPC+Fe

Tracking + dE/dx small cell + He/C2H5

CsI(Tl) 16X0

Aerogel Cherenkov counter + TOF counter

Si vtx. det. 3 lyr. DSSD

SC solenoid1.5T

8GeV e

3.5GeV e

2 pixel lyrs. + 4 lyr. DSSD tile scintillator

pure CsI (endcap)

remove inner lyrs.

“TOP” + RICH

New readout and computing systems


Motivation for much higher luminosity: I

• More precise determination of the Unitarity Triangle– Observables insensitive to new physics (1, Vub, 3 with tree diagrams)

are required as the SM references in searching for new physics– Clean e+e environment provides unique measurements

• isospin analysis (2)• 3 in several ways (with B DK etc.) • Vub with “mono-B” (full-reconstruction) technique

– Above methods have small theoretical uncertainties

300fb-1 3000fb-1_ _ plane


mono-B approach

Υ(4S)e- (8GeV) e+(3.5Gev)

B

B

Interesting decays•B → ul•B → •B → D•etc

full tagging

Unique at (4S)Need large statistics

@78fb-1


Vub measurement

Exclusive SL decay with mono-B (semileptonic tagging)Statistical error (q2>15GeV2) < 5% @ 3000fb-1

Systematic error under study Form factor from Lattice QCD !Precision with unquenced calculation ?

Inclusive SL decay withmono-B (full reconstruction)Statistical error < 3% @ 3000fb-1

Systematic error under study

Target: |Vub/Vcb| < 5%


Motivation for much higher luminosity: II

• Search for a 2nd source of CP violation– Many CP-violating phases in models beyond the SM

– A big discovery, as it is a clear manifestation of new physics

– Impact on baryogenesis (KM phase is not enough)

Example: b s transition CP violation “same” as J/Ks in the SMPenguin~O(2), Tree~O(4)

fS ( sin21 in the SM)2.7 deviation from the SMtriggered many speculations.Need more data !

Very “natural” place for new physics to appear

_b

_s

s_s


Expected confidence regions: I• 3000fb-1 (3ab-1): achievable with L=1035cm-2s-1)

B0 KSB0 ’KS

(sin21,0)

1significance

5significance

~

f f


Expected confidence regions: II• 30000fb-1 (30ab-1): achievable with L=1036cm-2s-1)

B0 KSB0 ’KS

1significance

5significance

~(sin21,0)

f fdeviation of ~0.1 can be detected with 5 significance !


sin21 = top-quark physics !

This will remain true when a new elementary particle is foundat a future energy frontier (e.g. LHC).e.g. SUSY off-diagonal couplings, phase at a “super” B factory

Top-quark physics Direct production, Mass, width etc. CDF/D0Off-diagonal couplings, phase BaBar/Belle

Phase in Vtd is the source of CP violation


Motivation for much higher luminosity: III

• Other new physics effects in loop/box diagrams

Example)


Motivation for much higher luminosity: IV

• Restrict (or even identify) new physics models

– by restricting couplings and phase of new particles with mass ~ 1TeV, which can be found at the energy frontier

– need to check a pattern of several theoretically/experimentally clean observables (Unitarity Triangle is a part of this game)

Similar to DNA identification


Exploring SUSY breaking mechanism

Representative SUSY models (4 different cases)• mSUGRA• SUSY-SU(5) with R (degenerate mass matrix)• SUSY-SU(5) with R (non-degenerate mass matrix)•MSSM with U(2) flavor symmetry

Goto,Okada,Shimizu,Shindou,TanakaPRD66, 035009 (2003)hep-ph/0306093

gluino mass

S(

Ks)


Difference in the pattern of deviation from SM

Bd- unitarity

m(Bs)

B->Ks B->Ms indirectCP

b->s

direct CP

mSUGRA - - - - - +SU(5)SUSY GUT + R

(degenerate)

- + + - + -

SU(5)SUSY GUT + R

(non-degenerate)

- - + ++ ++ +

U(2) Flavor symmetry

+ + + ++ ++ ++

Unitarity triangle Rare decay

Lattice QCD will play an essential role !

- : small deviation+: sizable++: large


Summary

• Progress expected in the next few years ( ~350fb-1) on

– the 2nd and 3rd angles

– direct CP violation

• KEK B factory has been operational quite successfully

– 159fb-1 recorded

– CP violation (78fb-1): sin21 = 0.7190.0740.035

– KM mechanism established as the dominant source of CP violation

– Many first observations of rare B decays and many other results

• Major upgrade for L=1035-1036cm-2s-1 ( 3000-30000fb-1)

– Very powerful and unique in exploring new phase and couplings


Backup slides


Vub measurement

More luminosityLe

ss s

yste

mat

ics

July 15-19, 2003 Lattice 2003, Tsukuba, Ibaraki, Japan Masashi Hazumi (KEK) 1 Masashi Hazumi (KEK)...

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