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 /1/20161

Introduction - Unitarity Triangle 3/1/20162 Wolfenstein parameterization Unitarity condition This defines the Unitarity Triangle Each term is O(λ 3 ) 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. (ρ, η) = ( ρ, η). (1-λ 2 /2) 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 |V ub | 2.

B A B AR Data 3/1/20163 End of Υ(4S) data Taking (2007) The entire Υ(4S) dataset has a integreted luminosity of about 426 fb -1 (467M BB)

Constraining the Unitarity Triangle - Sides Sides of the Triangle: We measure decay rates. ~ |V ij | 2 From exclusive sl decays: |V cb |: B  D*l, B  Dl ; |V cb |: B  D*l, B  Dl ; |V ub |: B  l, B  l, B  (‘)l, B  l. |V ub |: B  l, B  l, B  (‘)l, B  l. From inclusive B  X c l : |V cb | and B  X u l decays : |V ub | From radiative decays: (b  d  /b  s  )  |V td |/ |V ts | (b  d  /b  s  )  |V td |/ |V ts | inclusive and exclusive decays inclusive and exclusive decays 3/1/20164

|V ub | from B  πlv decays untagged PRL 98, (2007) Untagged (high stat., most precise)  Untagged (high stat., most precise)  Tagged (hadron or semileptonic) Untagged Analysis loose reconstruction: use the events' missing  loose reconstruction: use the events' missing momentum as an approximation to the signal momentum as an approximation to the signal neutrino. (p = p beams -  p i ) neutrino. (p = p beams -  p i ) Two-Dimensinal Fit  E = E B – s/2 and  Two-Dimensinal Fit  E = E B – s/2 and m ES = s/4-|p* B | 2 m ES = s/4-|p* B | 2 q 2 = (p B - p  ) 2 in 12 q 2 bins  Form factor fit  q 2 = (p B - p  ) 2 in 12 q 2 bins  Form factor fit 3/1/20165 untagged

|V ub | from B  πlv decays tagged Tagged Analysis with B → D(*)lν PRL101, (2008) Untagged (high stat., most precise)  Untagged (high stat., most precise) Tagged (hadron or semileptonic)  Tagged (hadron or semileptonic) 3/1/20166 Statistical error on the BF is 3 times larger than the untagged analysis. Compatible result with the untagged analysis. 348 fb -1

|V ub | from inclusive semileptonic decays PRL100, (2008) 3/1/20167 Integrated over optimized region in the phase space Tagged analysis, use B → D(*)lν as tags. |V ub | 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 |V ub |. theoretical error is the largest error on |V ub |. 347 fb -1

|V cb | with B → Dlν decays 3/1/20168 Many methods also for |V cb |: here is a tag exclusive analysis From PANIC fb -1

BABAR has used three different ways to obtain |V cb | from B → D*lν: 1) Fully reconstructed B 0  D* + lv (exclusive) 1) Fully reconstructed B 0  D* + lv (exclusive) 2) Fully reconstructed B +  D* 0 lv 2) Fully reconstructed B +  D* 0 lv 3) Combined fit to partially reconstructed Dlv and D*lv in D(n)lv events. 3) Combined fit to partially reconstructed Dlv and D*lv in D(n)lv events. 3/1/20169 Very consistent result |V cb | with B → D*lν decays

|V tb /V ts | from radiative decays |V td | is accessible through loops: radiative penguin B → XsB → Xs B → XdB → Xd PRL ,2008 Exclusive Inclusive 3/1/ arXiv: , accepted by PRD veto to photons  veto to photons from  0 and  from  0 and  Select high energy  Select high energy photons photons Yield from  E and m ES  Yield from  E and m ES See Bruce Schumm talk

Constraining the Unitarity Triangle - Angles Angles of the Triangle: Interference appears ~ |V ij | 2 3/1/ Interference between B mixing and decay Interference between two decays

Angle α Interference between B mixing and b  u Four solutions ambiguity Isospin analysis to resolve Δα 3/1/ α eff = α + Δα We have to measure A +-, A +0 and A 00

Angle α - Time-dependent CPV in B → π + π - Evidence of direct CP violation arXiv: [hep-ex] 3/1/ (3.0σ) (6.3σ) N ππ : 1394±54 B 0 tagged

Angle α - B → π o π o Contrains A 00 arXiv: [hep-ex] 3/1/201614

Angle α - B →ρρ Complication due to vector-vector is saved by f L (ρ + ρ - )~1. PRD78, (R) (2008) 3/1/ Smaller A 00 /A +0 means smaller error on Δα B(ρ 0 ρ 0 ) = (0.92 ± 0.32 ± 0.14) × 10 −6 Combined results ρ0ρ0ρ0ρ0 Measured range is compatible with the CKM fit

Angle β – Angle β – Benchmark sin2β arXiv: [hep-ex] = sin2β (SM) C = ± ± S = ± ± β = (21.8 ± 1.3) o HFAG average Decays: BaBar Results: sin2β 3/1/ CP odd J/Ψ K L

Angle β – B → η’K 0 and B → ωK 0 S Penguin diagram can change the CPV phase with new physics: This method gives larger errors on β. This method gives larger errors on β. η’K S ωK S (large error) η’K L 3/1/ arXiv: [hep-ex] No evidence of New Physics

Angle γ – B ± → DK (*)± Interference between Cabibbo-suppressed b → c and color-suppressed b → u tree decays D 0 and D 0 decays into the same final state 3/1/ Small CP asymmetry.

Angle γ – B ± → DK (*)± PRD (2008) D→KSπ+π-D→KSπ+π- D 0 (D 0 ) → K S π + π -, K S Κ + Κ - : Dalitz method (Giri, Grossman, Soffer, Zupan) Interference comes from overlap region on the Dalitz plot This method gives the smaller error 3/1/ DALITZ METHOD

Angle γ – B ± → DK (*)± PRD (2008) D 0 (D 0 ) → Kπ, Kππ 0, Kπππ : ADS method (Atwood, Dunietz, Soni) 3/1/ Interference between D 0 → Cabibbo-favored K - and D 0 → Doubly-Cabibbo-suppressed K - This method gives larger error (Only additional information to constrain γ) ADS METHOD Ratio Combined mode favored suppressed Kππ 0

Summary 3/1/ 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 V CKM.