a study of charmless hadronic two-body b decays at belle nov 30, 2007 yuuj i unno (hanyang)...
TRANSCRIPT
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
30 Nov, 2007 HaengDang Symposium 3
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
30 Nov, 2007 HaengDang Symposium 4
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
30 Nov, 2007 HaengDang Symposium 5
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
30 Nov, 2007 HaengDang Symposium 6
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 (^-^)!
30 Nov, 2007 HaengDang Symposium 7
Introduction (Direct CP violation)Introduction (Direct CP violation)
30 Nov, 2007 HaengDang Symposium 8
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
30 Nov, 2007 HaengDang Symposium 9
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)
30 Nov, 2007 HaengDang Symposium 10
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
30 Nov, 2007 HaengDang Symposium 11
Introduction (BIntroduction (Bhh)hh)
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 3 3 & new physics search& new physics search ))
from all Bhh
Time integrated analysis
( )BBrec.N
BBN ≡
ε+
Br( ) ( )
( ) ( )
BN BN
BN - BN ≡
+A CP
30 Nov, 2007 HaengDang Symposium 12
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
30 Nov, 2007 HaengDang Symposium 13
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
30 Nov, 2007 HaengDang Symposium 14
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
30 Nov, 2007 HaengDang Symposium 15
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.
30 Nov, 2007 HaengDang Symposium 16
AnalysisAnalysis
Result
Kinematical reconstruction
Continuum(qq) background suppression
Signal extraction
Kπ separation
30 Nov, 2007 HaengDang Symposium 17
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
30 Nov, 2007 HaengDang Symposium 18
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
30 Nov, 2007 HaengDang Symposium 19
Analysis Analysis (qq background suppression)
qq rejection power is ~90%, sig. eff. is ~70% for BKmode
Before cut on R
After cut on R
30 Nov, 2007 HaengDang Symposium 20
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
30 Nov, 2007 HaengDang Symposium 21
Analysis Analysis (Kπ separationKπ separation)
Efficiency Fake rate
K ~90% ~7%
π ~89% ~12%
ex) BK+π- selection
Before cut
After cut
30 Nov, 2007 HaengDang Symposium 22
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- )
30 Nov, 2007 HaengDang Symposium 23
Branching fraction measurementsBranching fraction measurements
30 Nov, 2007 HaengDang Symposium 24
Result of Br (signal extraction)
K+K-
K0K+
K0K0
K0π+
K0π0
K+π-
K+π0
π+π-
π+π0
signalfeed-acrossqqrare B
π0π0
30 Nov, 2007 HaengDang Symposium 25
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
30 Nov, 2007 HaengDang Symposium 26
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
30 Nov, 2007 HaengDang Symposium 27
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
30 Nov, 2007 HaengDang Symposium 28
Partial rate asymmetry Acp
30 Nov, 2007 HaengDang Symposium 29
Result of Acp (signal extraction)
B0K+π- B+K+π0
B+π+π0 B0π0π0
0B
+B
-B
0B
0B 0B
+B
-B
30 Nov, 2007 HaengDang Symposium 30
Result of Acp (signal extraction)
B+K0π+ B+K0K+
0B
0B
-B +B+B-B
B0K0K0
30 Nov, 2007 HaengDang Symposium 31
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
30 Nov, 2007 HaengDang Symposium 32
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
30 Nov, 2007 HaengDang Symposium 33
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
30 Nov, 2007 HaengDang Symposium 34
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…
30 Nov, 2007 HaengDang Symposium 35
Introduction (BIntroduction (Bhh)hh)
30 Nov, 2007 HaengDang Symposium 36
Systematics of Br(Bhh)
Systematics of FSR is about 1.0%
30 Nov, 2007 HaengDang Symposium 37
Systematics of π0π0
Br=1.1±0.3±0.1 04.0+ 73.0+ 0.06- 0.62- 44.0+=Acp
30 Nov, 2007 HaengDang Symposium 38
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
30 Nov, 2007 HaengDang Symposium 39
Acp(π0π0)
000ππ →B 000 ππ →B
signalqqrare BOff time QED
30 Nov, 2007 HaengDang Symposium 40
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
30 Nov, 2007 HaengDang Symposium 41
Systematics of Acp
detector bias of Kπ0,ππ0 from qq bkg in (ΔE, mbc) detector bias of Kπ from D*+ D0(Kπ)π+
30 Nov, 2007 HaengDang Symposium 42
Analysis Analysis (qq background suppression)
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
30 Nov, 2007 HaengDang Symposium 43
Analysis Analysis (qq background suppression)
(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
30 Nov, 2007 HaengDang Symposium 44
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)
30 Nov, 2007 HaengDang Symposium 45
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
30 Nov, 2007 HaengDang Symposium 46
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 %
30 Nov, 2007 HaengDang Symposium 47
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
30 Nov, 2007 HaengDang Symposium 48
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
30 Nov, 2007 HaengDang Symposium 49
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
30 Nov, 2007 HaengDang Symposium 50
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
30 Nov, 2007 HaengDang Symposium 51
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
30 Nov, 2007 HaengDang Symposium 52
Result of Br (comparison w/ others)
Consistent with other experiment results
30 Nov, 2007 HaengDang Symposium 53
Result of Acp (comparison w/ others)
Consistent with other experiment results
30 Nov, 2007 HaengDang Symposium 54
√s = 10.58 GeVe+e- (4S)BB
KEKBKEKB
30 Nov, 2007 HaengDang Symposium 55
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.
30 Nov, 2007 HaengDang Symposium 56
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