A study of charmless hadronic two-body B decays at Belle

A study of charmless hadronicA study of charmless hadronic two-body B decays at Belle two-body B decays at Belle A study of charmless hadronicA study of charmless hadronic two-body B decays at Belle two-body B decays at Belle

Nov 30, 2007Yuuj ｉ Unno (Hanyang)

HaengDang Symposium 2007 @Hanyang university.

30 Nov, 2007 HaengDang Symposium 2

ContentsContents

IntroductionIntroduction CP violationCP violation BBKπ, ππ, KKKπ, ππ, KK KEKB and BelleKEKB and Belle

AnalysisAnalysis Kinematic reconstructionKinematic reconstruction Continuum suppressionContinuum suppression Kπ separationKπ separation

ResultsResults Branching fractions Branching fractions Partial rate CP asymmetry (Acp)Partial rate CP asymmetry (Acp)

SummarySummary

IntroductionIntroduction CP violationCP violation BBKπ, ππ, KKKπ, ππ, KK KEKB and BelleKEKB and Belle

AnalysisAnalysis Kinematic reconstructionKinematic reconstruction Continuum suppressionContinuum suppression Kπ separationKπ separation

ResultsResults Branching fractions Branching fractions Partial rate CP asymmetry (Acp)Partial rate CP asymmetry (Acp)

SummarySummary


IntroductionIntroduction We live in the universe dominated by matter.

The matter and anti-matter were created in the equal amounts

Where have the anti-matter gone???

CP violation is one of the key to answer this mysterySakharov’s 3 conditions (1976)

(1) Baryon number violation

(2) Irreversible reaction

(3) CP violation (CPV) : CP = charge conjugation and parity transformation

CP conservation was believed for a long time CPV was discovered in K system in 1964.

Kobayashi-Maskawa(KM) model (in 1973) can explain


Introduction (KM model)Introduction (KM model)KM model predicted the existence of 3 generations, 6 quarks.Weak interaction induces CP violation within the Standard Model(SM)KM model predicted the existence of 3 generations, 6 quarks.Weak interaction induces CP violation within the Standard Model(SM)

CPV is due to a complex phase in quark mixing matrix

CPV is due to a complex phase in quark mixing matrix

..),,(2

gch

b

s

d

VWtcu

L

L

L

CKMLLL

Lagrangian of charged-current weak interaction

CP violationCP violationCP violationCP violation

Wolfenstein parameterization λ~0.2, A~O(1)

+O(λ4)

CKM matrixCKM matrixCKM matrixCKM matrix

CPV in K system was small ~ 0.1%

Large CPV in B system!!!Large CPV in B system!!!

Weinberg-Salam theory Quantum Chromo-dynamics


Introduction (KM matrix and unitarity triangle)Introduction (KM matrix and unitarity triangle)

Test KM model is important.Precise measurements of 3 angles and 3 side lengths.B meson system is best field!!!

Test KM model is important.Precise measurements of 3 angles and 3 side lengths.B meson system is best field!!!

unitarity

Unitarity triangleUnitarity triangleUnitarity triangleUnitarity triangle

bclv

BKπ

BB mixingBππ

bulv

BJ/ψKsBKsπ0


Introduction (CP violation in B system)Introduction (CP violation in B system)(1) (1) Mixing induced CP violation(Mixing induced CP violation(ICPVICPV)) : : Only neutral BOnly neutral B(1) (1) Mixing induced CP violation(Mixing induced CP violation(ICPVICPV)) : : Only neutral BOnly neutral B

Neutral B mix with box diagramInterference B0f and B0B0f leads CPV

(2) (2) Direct CP violation(Direct CP violation(DCPVDCPV)) : : Both charged and neutral B is possible Both charged and neutral B is possible (2) (2) Direct CP violation(Direct CP violation(DCPVDCPV)) : : Both charged and neutral B is possible Both charged and neutral B is possible

CPV from the mixing rate asymmetry.CPV from the mixing rate asymmetry.Decay time evolution info. Time-dependent analysisICPV in the B0J/ψKs has been observed in 2001 at Belle.

CPV in the decay process.CPV in the decay process.

NO time info. is necessary Time-integrated analysis

Large DCPV in B system is predicted!!! But no observation yet.

Simple (^-^)!


Introduction (Direct CP violation)Introduction (Direct CP violation)


Introduction (KM model and particle physics)Introduction (KM model and particle physics)

1964: 1964: Discovery of CPV in K decays (Fithch & Cronin et al.)Discovery of CPV in K decays (Fithch & Cronin et al.)

1967: Role of CPV in the creation of the universe (Sakarov’s 3 conditions)1967: Role of CPV in the creation of the universe (Sakarov’s 3 conditions)

1973: 1973: Kobayashi-Makawa(KM) model Kobayashi-Makawa(KM) model 6 quark, CPV 6 quark, CPV

1974: Discovery of 1974: Discovery of charm quarkcharm quark (Ting, Richter et al.) (Ting, Richter et al.)

1979: Discovery of 1979: Discovery of bottom quarkbottom quark (Lederman et al.) (Lederman et al.)

1981: Predict large CPV in neutral B meson system (Bigi, Carter, Sanda)1981: Predict large CPV in neutral B meson system (Bigi, Carter, Sanda)

1987: Discovery of large B1987: Discovery of large B00BB00 mixing(ARGUS) mixing(ARGUS)

1995: Discovery of 1995: Discovery of top quarktop quark (CDF, D0) (CDF, D0)

1999: Discovery of 1999: Discovery of DCPV in K decaysDCPV in K decays (KTeV, NA48) (KTeV, NA48)

2001: Discovery of 2001: Discovery of ICPV in B decaysICPV in B decays (Belle, Babar) (Belle, Babar)

20xx: 20xx: Is next DCPV in B decays??? or New physics???Is next DCPV in B decays??? or New physics???

We are working on the KM prediction loadWe are working on the KM prediction load

History of CP ViolationHistory of CP ViolationHistory of CP ViolationHistory of CP Violation


Introduction (BIntroduction (Bhh : Kπ/ππ/KK)hh : Kπ/ππ/KK)

Tree

Penguin

Color supp. Tree

Electro Weak Penguin

Annihilation

Color supp. EW Penguin Penguin Annihilation

W Exchange

Charmless hadronic two-body B decays,BKπ/Kπ0/K0π0/K0π0/ππ/ππ0/π0π0/KK/KK0/K0K0

provides rich information for CPV, CKM angles, new physics, B decay dynamics.

Charmless hadronic two-body B decays,BKπ/Kπ0/K0π0/K0π0/ππ/ππ0/π0π0/KK/KK0/K0K0

provides rich information for CPV, CKM angles, new physics, B decay dynamics.

Dominated by (bu Tree) and (bd, s Penguin)


Introduction (BIntroduction (Bhh)hh)

DCPV through an interference between T and P

φ2 by B0ππ time-dependent analysis Sππ ＝ sin2(φ2+Θ) isospin analysis in ππ system Br & Acp of ππ, ππ0, π0π0 is important

Need to understand hadronic uncertainties with all Bhh pQCD, QCD factorization, isospin, SU(3) symmetries,,,, φ3 extraction is theoretically challenging Coherent study of Bhh is important.

Ratios of Br(Bhh) are very useful.

DCPV through an interference between T and P

φ2 by B0ππ time-dependent analysis Sππ ＝ sin2(φ2+Θ) isospin analysis in ππ system Br & Acp of ππ, ππ0, π0π0 is important

Need to understand hadronic uncertainties with all Bhh pQCD, QCD factorization, isospin, SU(3) symmetries,,,, φ3 extraction is theoretically challenging Coherent study of Bhh is important.

Ratios of Br(Bhh) are very useful.

New physics???φ3

Penguin dominant modes aresensitive to new physics



BBhhhh

φ2 measurementφ2 measurement 　

from Bπ ＋ π

Time dependent analysis

φ1 (and new physics search)φ1 (and new physics search)

from bs penguin modes

Time dependent analysis

Br & Acp Br & Acp （（ & φ& φ ３３ & new physics search& new physics search ））

from all Bhh

Time integrated analysis

( )BBrec.N

BBN ≡

ε+

Br( ) ( )

( ) ( )

BN BN

BN - BN ≡

+A CP


Ring length 3Km

Two separate ring for e+ and e-

Energy in CM is 10.58GeV

B factory : e+e- (4S) BB (1.1nb)

Ring length 3Km

Two separate ring for e+ and e-

Energy in CM is 10.58GeV

B factory : e+e- (4S) BB (1.1nb)

Introduction (KEKB accelerator)Introduction (KEKB accelerator)

3.5 GeV e-

8.0GeV e+

Y(4S) BB many final states

Belle


Introduction (KEKB performance)Introduction (KEKB performance)In

tegr

ated

lum

inos

ity (/

fb)

　 Today’s results are based on

449 or 535 M BB (1.5 ~ 4 times larger than last pub.)

World record

Peak luminosity = 17.2 /nb/s

Integrated. luminosity. = 750 /fb

corresponding ＞ 650 M BB pairs

BB pairs are accumulated, -- recent event rate =~ 400Hz -- σ(e+e-(4S)) = 1nb

(400Hz)x(16.5/nb/s)x(1nb) =~ 66/s


3.5 GeV e＋

8.0 GeV e —

Introduction (Belle detector)Introduction (Belle detector)Aerogel Cherenkov Counter

Kπ separation

Central Drift Chamber

Charged track momentumKπ separation

KLMuon Detector

KL, μ detection

Silicon Vertex Detector

B vertex

TOF Counter

Kπ separation

Electromagnetic Calorimeter

γ, π0 reconstruction e ＋－ , KL identification


Introduction (Belle Collaboration)Introduction (Belle Collaboration)

14 countries 55 institutes

~400 collaborators

IHEP, ViennaITEPKanagawa U.KEKKorea U.Krakow Inst. of Nucl. Phys.Kyoto U. Kyungpook Nat’l U. EPF Lausanne Jozef Stefan Inst. / U. of Ljubljana / U. of MariborU. of Melbourne

BINPChiba U.U. of CincinnatiEwha Womans U.Fu-Jen Catholic U.U. of GiessenGyeongsang Nat’l U.Hanyang U.U. of HawaiiHiroshima Tech.IHEP, BeijingIHEP, Moscow

Nagoya U.Nara Women’s U.National Central U.National Taiwan U.National United U.Nihon Dental CollegeNiigata U.Nova GoricaOsaka 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 Agri. and Tech.INFN TorinoToyama Nat’l CollegeVPIYonsei U.


AnalysisAnalysis

Result

Kinematical reconstruction

Continuum(qq) background suppression

Signal extraction

Kπ separation


Analysis Analysis (kinematic reconstruction)

signal

e+e-qq(q=udsc)

feed-acrros(⇔K)

charmless rare B()

Charge track by CDC + SVD

K0K0Sπ+π-

π0γγ

B candidate with ΔE + mbc


Analysis Analysis (qq background suppression)

B

B+e -e

BB(σ~1nb) is spherical qq(σ~3nb) is jet-like

Suppress background by mainly using event topologySuppress background by mainly using event topology

Dominant background comes from e+e- Dominant background comes from e+e- qq(q=udsc) continuum process qq(q=udsc) continuum processDominant background comes from e+e- Dominant background comes from e+e- qq(q=udsc) continuum process qq(q=udsc) continuum process

u ＜　 0.1 GeV/c2

d ＜　 0.1 GeV/c2

s ～ 0.1 GeV/c2

c ～ 1 .25 GeV/c2

B ～ 5 .28 GeV/c2

Y(4S) ～ 10.58 GeV/c2

q

q

+e -e

Event topology is evaluated by

Fox-wolfram moment with fisher discriminant

Separate sig and bkg using likelihood method

Event topology is evaluated by

Fox-wolfram moment with fisher discriminant

Separate sig and bkg using likelihood method



qq rejection power is ~90%, sig. eff. is ~70% for BKmode

Before cut on R

After cut on R


Analysis Analysis (Kπ separationKπ separation)

Cherenkov light yield

Ionization energy loss

Charged particle emit cherenkov light(transition radiation)

if velocity is faster than that of light in material


Analysis Analysis (Kπ separationKπ separation)

Efficiency Fake rate

K ~90% ~7%

π ~89% ~12%

ex) BK+π- selection

Before cut

After cut


Continuum Mbc : Argus func.

ΔE : 2 cheby. func.

Charmless rare BSmoothed hist of MC

B0π+π-

Smoothed hist of MC

B0K+π- Smoothed hist. of MC

Analysis Analysis (signal extraction)Unbinned maximum likelihood fit on ΔE and mbcUnbinned maximum likelihood fit on ΔE and mbc

i = B candidate event j = sig/rare/qq/feed accros n = # of events q = +1 or –1 for B or B tag P = probability density func.

Example (B0 K+π- )


Branching fraction measurementsBranching fraction measurements


Result of Br (signal extraction)

K+K-

K0K+

K0K0

K0π+

K0π0

K+π-

K+π0

π+π-

π+π0

signalfeed-acrossqqrare B

π0π0


Result of Br

Clear Br hierarchy can be seen. Kπ ＞ ππ ＞ KK First observation of bd penguin K+K0 and K0K0

theoretical expectation (pQCD/QCDF) ~1x10-6

Observation of π0π0

# of events is still small to measure Acp to constraint φ2

Only missing is K+K- ultra-suppressed mode(W-exhange)

Black 449MBB Blue 535 MBB

BBrec.

Signal

Nε

N Br ≡

preliminary


Result of Br (ratios of Br)Result of Br (ratios of Br)

= Rc= Rn

Rations of Br can reduce systematics of experimental results hadronic uncertainty in theory calculationDiscussions with theoretical predictions can be done

Rations of Br can reduce systematics of experimental results hadronic uncertainty in theory calculationDiscussions with theoretical predictions can be done


Result of Br (discussion on Kπpuzzle)Result of Br (discussion on Kπpuzzle)A.J. Buras, R. Fleischer, et al.,Phys. J. C 45, 701-710 (2006)

q = PEW effect

φ=φ3

We were/are here in Rc-Rn

Kπ puzzle was vanished!

85MBB

449MBB


Partial rate asymmetry Acp


Result of Acp (signal extraction)

B0K+π- B+K+π0

B+π+π0 B0π0π0

0B

+B

-B

0B

0B 0B

+B

-B


Result of Acp (signal extraction)

B+K0π+ B+K0K+

0B

0B

-B +B+B-B

B0K0K0


Result of Acp Black 449 MBB Blue 535 MBB Green 535 MBB

Time-dep. analysis

Significant DCPV in K+π- and π+π-

DCPV in B meson system is now established

ΔAcp puzzle(?!) ΔAcp = Acp(K+π0) - Acp(K+π-) = +0.164±0.037 4.4σ

Significant DCPV in K+π- and π+π-

DCPV in B meson system is now established

ΔAcp puzzle(?!) ΔAcp = Acp(K+π0) - Acp(K+π-) = +0.164±0.037 4.4σ

Preliminary

Preliminary

(K+- = T + P) (K+0 = T + P)

Naïve theoretical expectation

ΔAcp = Acp(K+π0)-Acp(K+π-) ～ 0


Result of Acp (discussion on ΔAcp puzzle)

Enhancement of C ?

C ~T or C ＞ T

breakdown of theoretical understanding

Enhancement of PEW ?

Would indicate new physics.

No theory within SM exist so far.

Enhancement of C ?

C ~T or C ＞ T

breakdown of theoretical understanding

Enhancement of PEW ?

Would indicate new physics.

No theory within SM exist so far.

K+π-

K+π0

　 C.W.Chaing, et al., PRD 70, 034020

　 Y.Y.Charng, et al., PRD 71, 014036

　 W.S.Hou, et al., PRL 95, 141601

　 S.Baek, et al., PRD 71, 057502

　 S.Baek, et al., PLB 653, 249

　 H.Li,et al., PRD 72, 114005

　 C.W.Chaing, et al., PRD 70, 034020

　 Y.Y.Charng, et al., PRD 71, 014036

　 W.S.Hou, et al., PRL 95, 141601

　 S.Baek, et al., PRD 71, 057502

　 S.Baek, et al., PLB 653, 249

　 H.Li,et al., PRD 72, 114005

ΔAcp ~ 0 is expected by assuming low C and PEWΔAcp ~ 0 is expected by assuming low C and PEW


Result of Acp (discussion on ΔAcp puzzle) Further examination on ΔAcp puzzle

M. Gronau, PLB 672, 82-88

A precise sum rule among four BKπ CP asymmetries

A violation of the sum rule would be evidence of new physics.

The sum rule predicts Acp(K0π0) = - 0.15±0.06

Different(?!) from the prediction

δAcp(K0π0) is still too large to claim a discrepancy.

Have to examine this at Super-B stage

The sum rule predicts Acp(K0π0) = - 0.15±0.06

Different(?!) from the prediction

δAcp(K0π0) is still too large to claim a discrepancy.

Have to examine this at Super-B stage


Summary

Study of Bhh plays significant roles CPV search CKM angle determination New physics search B decay dynamics understanding

Branching fraction measurements Measure Br of all Bhh modes Kπ puzzle was gone First observations of bd penguin BKK0, K0K0

Only missing is B0K+K-(W-exhange)

Acp measurements Direct CP violation in B0K+π- and +- are established ΔAcp puzzle is found with 4.4σ !!!

ΔAcp puzzle have to be published ASAP…

Study of Bhh plays significant roles CPV search CKM angle determination New physics search B decay dynamics understanding

Branching fraction measurements Measure Br of all Bhh modes Kπ puzzle was gone First observations of bd penguin BKK0, K0K0

Only missing is B0K+K-(W-exhange)

Acp measurements Direct CP violation in B0K+π- and +- are established ΔAcp puzzle is found with 4.4σ !!!

ΔAcp puzzle have to be published ASAP…


Systematics of Br(Bhh)

Systematics of FSR is about 1.0%


Systematics of π0π0

Br=1.1±0.3±0.1 04.0+ 73.0+ 0.06- 0.62- 44.0+=Acp


Systematics of π0π0

with 277MBB (last published data set) QED bkg is considered only in systematics

(New cut with new LR)

(New cut with new LR)

Why did Br(π0π0) decrease?

Main reason is just statistics fluctuation.

Second one is Good treatment of QED background.

with 535 MBB

Good treatment of QED bkg decrease Br slightly


Acp(π0π0)

000ππ →B 000 ππ →B

signalqqrare BOff time QED


π0π0 : Off time QED background

~5.28GeV/c2

Bhabha events

Time information Off-time events

CsI trigger time

Define • On -time• Off-time

cosΘ1cosΘ2 Emiss


Systematics of Acp

detector bias of Kπ0,ππ0 　 from qq bkg in (ΔE, mbc) detector bias of Kπ 　 from D*+ 　　 D0(Kπ)π+



q

q

+e -e

B

B+e -e

Modified Fox-wolfram moment with fisher discriminant

BB is spherical qq is jet-like(1) Event topology(1) Event topology

)/sθ(cosPppΣ H ijnjiijn ≡

Sig & non-Sig Non-sig & non-sig Transverse mom.

17 coefficients of fishersingle variable

Dominant background comes from e+e- Dominant background comes from e+e- qq(q=udsc) continuum process qq(q=udsc) continuum process



(2) cosB : B flight direction (Jp conservation in decay)

BB 1-cosB vs qq uniform

(3) Likelihood approach

qq rejection power is ~90%, sig. eff. is ~70% for BKmode

KSFW


Analysis Analysis (High momentum Kπ separation : KIDHigh momentum Kπ separation : KID)

D*+D0(K-+)+S

Very clean

can identify K andπ by S

Eff.(%) Fake(%)

K ＋ 81.87±0.43 6.54±0.51

K ー 82.45±0.46 6.97±0.46

＋ 89.49±0.52 12.30±0.45

ー 88.75±0.43 11.99±0.43

Charge asymmetry bias is corrected in the signal extraction.Charge asymmetry bias is corrected in the signal extraction.

Δm=m(D*+)-m(D0)


Analysis Analysis (KID correction: ex. B0K)

trueCPmeas

+π-Kmeas

-π+K

meas+π-K

meas-π+Kmeas

CP A N + N

N - N A ≠≡

trueCP

trueCPmeas

CP A)f+f-ε+ε-(+)f+f+ε+ε+(

A )f-f-ε+ε+(+)f-f+ε+ε-(=A

Belle KID has high performance BUT NOT PERFECT

　 Existence of KID charge asymmetry smears true Acp

　 Finite KID fake dilutes true Acp : K ＋ K

To obtain true Acp, introduce KID correction

B0K : 1% correction is applied

+π

-K

-π

+K ff=f ff=f

+π

-K

-π

+K εε=ε εε=ε


NIM A 533, 516 (2004)

Flavor taggingFlavor taggingb flavor information is needed for non-flavor-specific B0 modes

Judge tag side B flavor with flavor specific processes

Charge of lepton / Kaon / slow-pion.

Tagging efficiency is 30 %


Analysis Analysis (Signal extraction)

[ ] )E(ρ )θcos,θ(cosρ )EΔ,m(ρ )ω2-1( )χ2-1( Acp q-1 21

=P miss21jbcjjdjj

- j

)PNΣ(Π!N

)NΣexp(=L jjji

j

(3)π0π0

)EΔ,m(ρ )Acp q-1(21

=P jbcjjjj

[ ] )EΔ,m(ρ )ω2-1( )χ2-1( Acp q-1 21

=P jbcjjdjj

j = signal/rare/qq/feed accros

q = +1 or –1 for B0 or B0 tagXd= time-integrated mixing param. w = wrong tag fraction (mis-identification of flavor)

Signal extraction is performed withunbinned maximum likelihood fit on ΔE and mbc(or more).

Signal extraction is performed withunbinned maximum likelihood fit on ΔE and mbc(or more).

Likelihood is

(1)flavor specific modes(B+, B0K+π-)

(2)other neutral B modes

Simultaneous fit on B and BSimultaneous fit on B and B


Analysis Analysis (Signal extraction)How to determine the PDF (1) MC simulation There is small correlation in ΔE and mbc, so,

Signal smoothed histogram of MC Feed-accros smoothed histogram of MC rare B smoothed histogram of MC continuum Argus func.(mbc) & chebychev func(ΔE)

(2) Calibration Detector response of MC is different from data. PDF of MC is calibrated with

high statistics and similar kinematic control samples.Mode Control sample

B h ＋ h ＋ , K0 h ＋ B ＋ D0(K ＋＋ ) ＋　　 & inclusive D0 K ＋＋ B h ＋ 0, K00 B ＋ D0(K ＋＋ 0) ＋ & inclusive D0 K ＋＋ 0

B0 K0K0 B ＋ D0(K0 ＋＋ ) ＋ & inclusive D0 K0 ＋＋

B0 00 B ＋ D0(K ＋＋ 0) ＋　 & inclusive D0 00


KEKB performanceKEKB performance Peak luminosity = 16.5 /nb/s

BB pairs are produced, Recent event rate =~ 400Hz σ(e+e-(4S)) = 1nb

(400Hz)x(16.5/nb/s)x(1nb) =~ 66/s


Br(Bπ0π0) : signal extraction Off timing QED background fake π0π0

To distinguish, introduce 3 variables cosΘ1 : high momentum π0

cosΘ2 : low momentum π0

Emiss : missing energy of other B

5D(ΔE, mbc, cosΘ1, cosΘ2, Emiss) UML fit

+e

q

q

-e

tEnergy deposit in CsI

)PNΣ(Π!N

)NΣ-exp(=L jjji

jj

)E(ρ )θcos,θ(cosρ )EΔ,m(ρ )Acpq-1(21

=P miss21jbcjjjj

signalqqrare BOff time QED


B factory experimentB factory experiment

Two B factories in operation since 1999

Many processes exist e+e ＋ e+e (Bhabha) Large e+e ＋ ~1

nb e+e ＋ ~1 nb e+e ＋ qq (q=u,d,s,c) ~3 nb e+e ＋ (4S) ＋ BB ~1 nb Other Belle special process

Main purpose is to study CPV with the B meson.Main purpose is to study CPV with the B meson.ee++ee-- (4S) (4S) BB (1.1nb) BB (1.1nb) ： √： √ S = 10.58 GeVS = 10.58 GeVMain purpose is to study CPV with the B meson.Main purpose is to study CPV with the B meson.ee++ee-- (4S) (4S) BB (1.1nb) BB (1.1nb) ： √： √ S = 10.58 GeVS = 10.58 GeV

PEPII collider for BaBar at SLACKEKB collider for Belle at KEK

++

τ Two-photon

CharmOthers(5S)Bs (3S),,,

Many physics activities


Result of Br (comparison w/ others)

Consistent with other experiment results


Result of Acp (comparison w/ others)

Consistent with other experiment results


√s = 10.58 GeVe+e- (4S)BB

KEKBKEKB


Introduction Introduction ((Sakharov’s three conditions))

(1) Anti-baryon has to disappear. There has to be baryon number violation.(2) Only anti-baryon has to disappear. There has to be CP violation.(3) Created asymmetry will be washed out if the universe is in equilibrium. Baryon has to be created out of

equilibrium.


ΔAcp puzzle Belle

Acp(K+π-) = -0.094±0.018±0.008

Acp(K+π0) = +0.07±0.03±0.01 　

ΔAcp = Acp(K+π0) - Acp(K+π-) = +0.164±0.037 (4.4σ)

Probability for no difference is ＜ 9.3x10-6

BabarAcp(K+π-) = -0.107±0.018+0.007

-0.004 　 (PLR 99,021603(2007))

Acp(K+π0) = +0.030±0.039±0.010 (arXiv:0707.2798)

ΔAcp = +0.137+0.045-0.044 　 (3.0σ)

Belle + Babar

ΔAcp = +0.152±0.029 　 5.2σ

Belle Acp(K+π-) = -0.094±0.018±0.008

Acp(K+π0) = +0.07±0.03±0.01 　

ΔAcp = Acp(K+π0) - Acp(K+π-) = +0.164±0.037 (4.4σ)

Probability for no difference is ＜ 9.3x10-6

BabarAcp(K+π-) = -0.107±0.018+0.007

-0.004 　 (PLR 99,021603(2007))

Acp(K+π0) = +0.030±0.039±0.010 (arXiv:0707.2798)

ΔAcp = +0.137+0.045-0.044 　 (3.0σ)

Belle + Babar

ΔAcp = +0.152±0.029 　 5.2σ

A study of charmless hadronic two-body B decays at Belle

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Transcript of A study of charmless hadronic two-body B decays at Belle