update on measurement of the angles and sides of the unitarity triangle at babar
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Update on Measurement of the angles and sides of the Unitarity Triangle at BaBar. Martin Simard Université de Montréal For the B A B AR Collaboration 12/20/2008 MIAMI 2008. 11/8/2014. 1. Introduction - Unitarity Triangle. ( ρ , η ) = ( ρ , η ) . (1- λ 2 /2). - PowerPoint PPT PresentationTRANSCRIPT
Update on Update on Measurement of the Measurement of the
angles and sides of the angles and sides of the Unitarity Triangle at Unitarity Triangle at
BaBarBaBarMartin SimardMartin Simard
Université de MontréalUniversité de MontréalFor the BFor the BAABBARAR Collaboration Collaboration
12/20/200812/20/2008MIAMI 2008MIAMI 2008
04/20/23 1
Introduction - Unitarity TriangleIntroduction - Unitarity Triangle
04/20/23 2
Wolfenstein parameterization Wolfenstein parameterization
Unitarity conditionUnitarity condition
This defines the Unitarity TriangleThis defines the Unitarity Triangle
Each term is O(λEach term is O(λ33))
The main goal of the B-factory is The main goal of the B-factory is to over-constrain the unitarity to over-constrain the unitarity triangle by measuring angles and triangle by measuring angles and sides in as many ways as sides in as many ways as possible.possible.
(ρ,η) = (ρ,η).(1-λ2/2)
Quark flavor changes can only Quark flavor changes can only occur through weak interactions, occur through weak interactions, via the coupling of a W gauge via the coupling of a W gauge boson. Such couplings are boson. Such couplings are proportional to the relevant CKM proportional to the relevant CKM matrix elements. In particular, the matrix elements. In particular, the probability of a b quark to decay probability of a b quark to decay into a u quark is proportional to |into a u quark is proportional to |VVubub||22..
BBAABBARAR Data Data
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End of Υ(4S) data Taking (2007)End of Υ(4S) data Taking (2007)
The entire Υ(4S) dataset has a The entire Υ(4S) dataset has a integreted luminosity ofintegreted luminosity ofabout 426 fbabout 426 fb-1 -1 (467M BB)(467M BB)
Constraining the Unitarity Triangle - SidesConstraining the Unitarity Triangle - Sides
Sides of the TriangleSides of the Triangle: We measure decay rates.: We measure decay rates. ~ |V~ |Vijij||22
From exclusive sl decaysFrom exclusive sl decays: : |V|Vcbcb|: B|: BD*lD*l, B, BDlDl; ; |V|Vubub|: B|: Bll, B, Bll, B, B(‘)l(‘)l, B, Bll..
From inclusive BFrom inclusive BXXccll: : |V|Vcbcb||and Band BXXuull decays decays : : |V|Vubub||
From radiative decaysFrom radiative decays:: (b(bdd/b/bss) ) |V|Vtdtd|/ |V|/ |Vtsts|| inclusive and exclusive decaysinclusive and exclusive decays
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|V|Vubub| from B| from Bππlv decays untaggedlv decays untagged
PRL 98, 091801(2007)PRL 98, 091801(2007)
Untagged Untagged (high stat., most precise)(high stat., most precise) Tagged (hadron or semileptonic)
Untagged AnalysisUntagged Analysis
loose loose reconstruction: use the events' reconstruction: use the events' missing missing momentum as an approximation to the momentum as an approximation to the signal signal neutrino. (pneutrino. (p = p = pbeamsbeams - - ppii))
Two-Dimensinal Fit Two-Dimensinal Fit E = EE = EBB– s/2 and – s/2 and mmES ES = s/4-|p*= s/4-|p*BB||22
qq22= (p= (pBB - p - p ) )22 in 12 q in 12 q22 bins bins Form factor Form factor fitfit
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untagged
|V|Vubub| from B| from Bππlv decays taggedlv decays tagged
Tagged AnalysisTagged Analysis with with B→D(*)lνB→D(*)lν
PRL101, 081801 (2008)PRL101, 081801 (2008)
Untagged Untagged (high stat., most precise)(high stat., most precise) Tagged Tagged (hadron or semileptonic)(hadron or semileptonic)
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Statistical error on the BF is Statistical error on the BF is 3 times larger than the 3 times larger than the untagged analysis.untagged analysis.
Compatible result with the Compatible result with the untagged analysis.untagged analysis.
348 fb-1
|V|Vubub| from inclusive semileptonic | from inclusive semileptonic decaysdecays
PRL100, 171802 (2008)PRL100, 171802 (2008)
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Integrated over optimized Integrated over optimized region in the phase spaceregion in the phase space
Tagged analysis, use B→D(*)lν as tags.Tagged analysis, use B→D(*)lν as tags.
|V|Vubub| values are higher than from exclusive semileptonic B| values are higher than from exclusive semileptonic Bππlv decays:lv decays:-> -> More DataMore Data is needed and is needed and improvement from theoryimprovement from theory is also needed. is also needed. theoretical error is the largest error on |Vtheoretical error is the largest error on |Vubub|.|.
347 fb-1
|V|Vcbcb| with B→Dlν decays| with B→Dlν decays
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Many methods also for |VMany methods also for |Vcbcb|: here is a tag exclusive analysis|: here is a tag exclusive analysis
From PANIC08
417 fb417 fb-1-1
BABAR has used three different ways to obtain |VBABAR has used three different ways to obtain |Vcbcb| from B→D*lν:| from B→D*lν: 1) Fully reconstructed B1) Fully reconstructed B00D*D*++lv (exclusive)lv (exclusive) 2) Fully reconstructed B2) Fully reconstructed B++D*D*00lvlv 3) Combined fit to partially reconstructed Dlv and D*lv in D(n)lv 3) Combined fit to partially reconstructed Dlv and D*lv in D(n)lv events. events.
04/20/23 9Very consistent resultVery consistent result
|V|Vcbcb| with B→D*lν decays| with B→D*lν decays
|V|Vtbtb/V/Vtsts| from radiative decays| from radiative decays|V|Vtdtd| is accessible through loops| is accessible through loops: radiative penguin: radiative penguin
B → Xs
B → Xd
PRL 101 111801,2008PRL 101 111801,2008
ExclusiveExclusive
InclusiveInclusive
04/20/23 10arXiv: 0808.1379, accepted by PRDarXiv: 0808.1379, accepted by PRD
veto to photons veto to photons from from 00 and and
Select high energy Select high energy photonsphotons
Yield from Yield from E and mE and mESES
See Bruce Schumm talkSee Bruce Schumm talk
Constraining the Unitarity Triangle - AnglesConstraining the Unitarity Triangle - Angles
Angles of the TriangleAngles of the Triangle: Interference appears: Interference appears ~ |V~ |Vijij||22
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Interference Interference between B mixing between B mixing and decayand decay
Interference Interference between two decaysbetween two decays
Angle Angle αα
Interference between B mixing and bInterference between B mixing and buu
Four solutions ambiguityFour solutions ambiguity
Isospin analysis to resolve ΔαIsospin analysis to resolve Δα
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ααeffeff = = αα + Δα + Δα
We have to measure AWe have to measure A+-+-, A, A+0+0 and A and A0000
Angle Angle αα - - Time-dependent CPV in B→πTime-dependent CPV in B→π++ππ--
Evidence of direct CP violationEvidence of direct CP violation
arXiv: 0807.4226 [hep-ex]arXiv: 0807.4226 [hep-ex]04/20/23 13
(3.0σ)(3.0σ)
(6.3σ)(6.3σ) Nππ: 1394±54
B0 tagged
B0 tagged
Angle Angle αα - - B→πB→πooππoo Contrains A Contrains A0000
arXiv: 0807.4226 [hep-ex]arXiv: 0807.4226 [hep-ex]
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Angle Angle αα - - B→B→ρρρρ
Complication due to vector-Complication due to vector-vector is saved by fvector is saved by fLL(ρ(ρ++ρρ--)~1.)~1.
PRD78, 071104(R) (2008)PRD78, 071104(R) (2008)
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Smaller ASmaller A0000/A/A+0+0 means means smaller error on Δαsmaller error on Δα
B(B(ρρ00ρρ00) = (0.92 ± 0.32 ± 0.14) × 10) = (0.92 ± 0.32 ± 0.14) × 10−6−6
Combined resultsCombined results
ρ0ρ0
Measured range is Measured range is compatible with the CKM fitcompatible with the CKM fit
Angle Angle ββ – – Benchmark sin2β
arXiv: 0808.1903 [hep-ex]arXiv: 0808.1903 [hep-ex]
= sin2β = sin2β (SM)(SM)
C = 0.026 ± 0.020 ± C = 0.026 ± 0.020 ± 0.0160.016S = 0.691 ± 0.029 ± S = 0.691 ± 0.029 ± 0.0140.014ββ = (21.8 ± 1.3) = (21.8 ± 1.3)oo
HFAG averageHFAG average
Decays:Decays:
BaBar Results:BaBar Results:
sin2β04/20/23 16
CP odd
J/Ψ KL
Angle Angle ββ – B→η’K – B→η’K00 and B→ωK and B→ωK00SS
Penguin diagram can change the CPV phase with new physics:Penguin diagram can change the CPV phase with new physics: This method gives larger errors on This method gives larger errors on ββ..
η’Kη’KSSωKωKS S (large error)(large error)η’Kη’KLL
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arXiv: 0809.1174 [hep-ex]arXiv: 0809.1174 [hep-ex]
No evidence of New PhysicsNo evidence of New Physics
Angle Angle γγ – – BB±±→DK→DK(*)±(*)±
Interference between Cabibbo-suppressed Interference between Cabibbo-suppressed b→c b→c and color-suppressed b→u tree decaysand color-suppressed b→u tree decays
DD00 and D and D00 decays into the same final state decays into the same final state04/20/23 18
Small CP asymmetry.Small CP asymmetry.
Angle Angle γγ – – BB±±→DK→DK(*)±(*)±
PRD 78 034023 (2008)PRD 78 034023 (2008)
D→KSπ+π-
DD00(D(D00)→K)→KSSππ++ππ--, K, KSSΚΚ++ΚΚ- - : Dalitz method (Giri, Grossman, Soffer, Zupan) : Dalitz method (Giri, Grossman, Soffer, Zupan)
Interference comes from overlap region on the Dalitz plotInterference comes from overlap region on the Dalitz plot
This method gives the smaller errorThis method gives the smaller error
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DALITZ METHODDALITZ METHOD
Angle Angle γγ – – BB±±→DK→DK(*)±(*)±
PRD 78 034023 (2008)PRD 78 034023 (2008)
DD00(D(D00)→ Kπ, Kππ)→ Kπ, Kππ00, Kπππ : ADS method (Atwood, Dunietz, Soni), Kπππ : ADS method (Atwood, Dunietz, Soni)
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Interference between DInterference between D00→Cabibbo-favored K→Cabibbo-favored K-- and Dand D00→Doubly-Cabibbo-suppressed K→Doubly-Cabibbo-suppressed K--
This method gives larger error This method gives larger error (Only additional information to constrain (Only additional information to constrain γγ))
ADS METHODADS METHOD
Ratio
Combinedmode
favored
suppressed
Kππ0
SummarySummary
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All these observations are in agreement with each other.All these observations are in agreement with each other.The combined fit to all observations leads to these sides and The combined fit to all observations leads to these sides and angles of the unitarity triangle.angles of the unitarity triangle.
No evidence of new physics: The SM describe what we observe.No evidence of new physics: The SM describe what we observe.
KobayashiKobayashi and and MaskawaMaskawa: 2008 Nobel Prize in Physics : 2008 Nobel Prize in Physics for introducing the third quark generation into the SM for introducing the third quark generation into the SM which explains CP violation by quark mixing with the which explains CP violation by quark mixing with the matrix Vmatrix VCKMCKM..