1 / 21

Update on Measurement of the angles and sides of the Unitarity Triangle at BaBar

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).

zahir-robles
Télécharger la présentation

Update on Measurement of the angles and sides of the Unitarity Triangle at BaBar

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Update on Measurement of the angles and sides of the Unitarity Triangle at BaBar Martin Simard Université de Montréal For the BABAR Collaboration 12/20/2008 MIAMI 2008 11/8/2014 1

  2. Introduction - Unitarity Triangle (ρ,η) = (ρ,η).(1-λ2/2) Wolfenstein parameterization Quark flavor changes can only occur through weak interactions, via the coupling of a W gauge boson. Such couplings are proportional to the relevant CKM matrix elements. In particular, the probability of a b quark to decay into a u quark is proportional to |Vub|2. Unitarity condition Each term is O(λ3) This defines the Unitarity Triangle The main goal of the B-factory is to over-constrain the unitarity triangle by measuring angles and sides in as many ways as possible. 11/8/2014 2

  3. BABAR Data End of Υ(4S) data Taking (2007) The entire Υ(4S) dataset has a integreted luminosity of about 426 fb-1 (467M BB) 11/8/2014 3

  4. Constraining the Unitarity Triangle - Sides ~ |Vij|2 Sides of the Triangle: We measure decay rates. From radiative decays: (bd/bs)  |Vtd|/ |Vts| inclusive and exclusive decays From exclusive sl decays: |Vcb|: BD*l, BDl; |Vub|: Bl, Bl, B(‘)l, Bl. From inclusive BXcl: |Vcb| and BXul decays : |Vub| 11/8/2014 4

  5. |Vub| from Bπlv decays untagged untagged  Untagged (high stat., most precise)  Tagged (hadron or semileptonic) Untagged Analysis  loose  reconstruction: use the events' missing momentum as an approximation to the signal neutrino. (p = pbeams - pi)  Two-Dimensinal Fit E = EB– s/2 and mES = s/4-|p*B|2 • q2= (pB - p )2 in 12 q2 bins  Form factor fit PRL 98, 091801(2007) 11/8/2014 5

  6. |Vub| from Bπlv decays tagged  Untagged (high stat., most precise)  Tagged (hadron or semileptonic) Tagged Analysis with B→D(*)lν Statistical error on the BF is 3 times larger than the untagged analysis. Compatible result with the untagged analysis. 348 fb-1 11/8/2014 6 PRL101, 081801 (2008)

  7. |Vub| from inclusive semileptonic decays Integrated over optimized region in the phase space Tagged analysis, use B→D(*)lν as tags. 347 fb-1 PRL100, 171802 (2008) |Vub| values are higher than from exclusive semileptonic Bπlv decays: -> More Data is needed and improvement from theory is also needed. theoretical error is the largest error on |Vub|. 11/8/2014 7

  8. |Vcb| with B→Dlν decays Many methods also for |Vcb|: here is a tag exclusive analysis 417 fb-1 From PANIC08 11/8/2014 8

  9. |Vcb| with B→D*lν decays BABAR has used three different ways to obtain |Vcb| from B→D*lν: 1) Fully reconstructed B0D*+lv (exclusive) 2) Fully reconstructed B+D*0lv 3) Combined fit to partially reconstructed Dlv and D*lv in D(n)lv events. Very consistent result 11/8/2014 9

  10. |Vtb/Vts| from radiative decays |Vtd| is accessible through loops: radiative penguin See Bruce Schumm talk Exclusive Inclusive • Select high energy photons B→ Xsg • veto to photons from 0 and   Yield from E and mES B→ Xdg PRL 101 111801,2008 11/8/2014 10 arXiv: 0808.1379, accepted by PRD

  11. Constraining the Unitarity Triangle - Angles ~ |Vij|2 Angles of the Triangle: Interference appears Interference between B mixing and decay Interference between two decays 11/8/2014 11

  12. Angle α Interference between B mixing and bu Four solutions ambiguity Isospin analysis to resolve Δα αeff = α + Δα We have to measure A+-, A+0 and A00 11/8/2014 12

  13. Angle α - Time-dependent CPV in B→π+π- B0 tagged Nππ: 1394±54 (6.3σ) (3.0σ) B0 tagged Evidence of direct CP violation arXiv: 0807.4226 [hep-ex] 11/8/2014 13

  14. Angle α - B→πoπo Contrains A00 arXiv: 0807.4226 [hep-ex] 11/8/2014 14

  15. Angle α - B→ρρ Measured range is compatible with the CKM fit Smaller A00/A+0 means smaller error on Δα Combined results Complication due to vector-vector is saved by fL(ρ+ρ-)~1. PRD78, 071104(R) (2008) ρ0ρ0 B(ρ0ρ0) = (0.92 ± 0.32 ± 0.14) × 10−6 11/8/2014 15

  16. Angle β – Benchmark sin2β CP odd = sin2β (SM) Decays: BaBar Results: J/Ψ KL C = 0.026 ± 0.020 ± 0.016 S = 0.691 ± 0.029 ± 0.014 β = (21.8 ± 1.3)o arXiv: 0808.1903 [hep-ex] HFAG average 11/8/2014 16 sin2β

  17. Angle β – B→η’K0 and B→ωK0S Penguin diagram can change the CPV phase with new physics: This method gives larger errors on β. arXiv: 0809.1174 [hep-ex] ωKS (large error) η’KS η’KL 11/8/2014 17 No evidence of New Physics

  18. Angle γ – B±→DK(*)± Interference between Cabibbo-suppressed b→c and color-suppressed b→u tree decays Small CP asymmetry. D0 and D0 decays into the same final state 11/8/2014 18

  19. Angle γ – B±→DK(*)± D0(D0)→KSπ+π-, KSΚ+Κ- : Dalitz method (Giri, Grossman, Soffer, Zupan) Interference comes from overlap region on the Dalitz plot This method gives the smaller error DALITZ METHOD D→KSπ+π- 11/8/2014 19 PRD 78 034023 (2008)

  20. Angle γ – B±→DK(*)± D0(D0)→ Kπ, Kππ0, Kπππ : ADS method (Atwood, Dunietz, Soni) Interference between D0→Cabibbo-favored K- and D0→Doubly-Cabibbo-suppressed K- This method gives larger error (Only additional information to constrain γ) ADS METHOD favored Kππ0 Ratio Combined mode suppressed 11/8/2014 20 PRD 78 034023 (2008)

  21. Summary All these observations are in agreement with each other. The combined fit to all observations leads to these sides and angles of the unitarity triangle. No evidence of new physics: The SM describe what we observe. Kobayashi and Maskawa: 2008 Nobel Prize in Physics for introducing the third quark generation into the SM which explains CP violation by quark mixing with the matrix VCKM. 11/8/2014 21

More Related