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Fernando Martínez-Vidal, On behalf of the BaBar Collaboration

Measurements of the CKM angle g at BaBar. Fernando Martínez-Vidal, On behalf of the BaBar Collaboration. CKM angle g. Apex of the CKM Unitary Triangle (UT) over constrained Precise measurement of SM parameters Search for NP in discrepancies of redundant measurements

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Fernando Martínez-Vidal, On behalf of the BaBar Collaboration

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  1. Measurements of the CKM angle g at BaBar Fernando Martínez-Vidal, On behalf of the BaBar Collaboration

  2. CKM angle g • Apex of the CKM Unitary Triangle (UT) over constrained • Precise measurement of SM parameters • Search for NP in discrepancies of redundant measurements • Still have some work to do on g: less precisely known UT angle (most difficult to measure) CP violation measurements give angles Semileptonic decay rates (and other methods) give sides See also UTfit analysis at http://www.utfit.org/ Very impressive consistency 1 ICHEP 2010, Paris Fernando Martinez Vidal

  3. CKM angle g • Apex of the CKM Unitary Triangle (UT) over constrained • Precise measurement of SM parameters • Search for NP in discrepancies of redundant measurements • Still have some work to do on g: less precisely known UT angle (most difficult to measure) CP violation measurements give angles Semileptonic decay rates (and other methods) give sides • Important to measure g since, together with |Vub|, selects r-h value independently of most types of NP • SM candle type of measurement • The constraint on g come from tree-level B→DK decays Experiments providing most of analyses today This talk 3.1 GeV e+ 9 GeV e– 468M BB pairs 3.5 GeV e+ 8 GeV e– 657M BB pairs ~10-15o 1 ICHEP 2010, Paris Fernando Martinez Vidal

  4. γ from B→DK decays Measure interference between tree amplitudes b→u and b→c B * • Use final state accessible from both D0 and D0 • Largely unaffected by New Physics • Clear theoretical interpretation of observables in terms of γ • Difficult because BFs are small due to CKM suppresion (10-5-10-7, so not many events) and rB=|Aub|/|Acb|is small due to further CKM and color suppressions (small interference) • All measurements are statistics limited * B 2 ICHEP 2010, Paris ICHEP 2010, Paris Fernando Martinez Vidal

  5. Dalitz plot ADS GLW K- K+ π0 π+ π- K+ π- CP-even π+ π- K+ π-π0 K0s π+ π- K0s K+ K- K0s π0 K0s ω CP-odd K0s Φ CP-conj CP-conj CP-conj γ from B→DK decays Neutral B→D(*)0K*0 Charged B→D(*)0K(*) B rB~0.1 rB~0.3 Dalitz plot f = K0s π+ π- ADS K+π-π0 K+ π- π+ π- K+π- K+π-π+ π- * f = CP-conj * • Complementary methods applied on same B decay modes share the same hadronic parameters (rB, dB) and g • Strategy: many decay chains are analyzed and then combined to improve the overall sensitivity to γ • In this talk we present new or recent results B Atwood, Dunietz, Soni, PRL 78, 3357 (1997) 3 ICHEP 2010, Paris ICHEP 2010, Paris Gronau, London, Wyler, PLB 253, 483 (1991); PLB 265, 172 (1991)

  6. γ from B→DK decays Dalitz plot method No D-mixing nor CPV Decay amplitude D0 decay strong phase variation Hadronic parameters rB=|A(b→u)|/|A(b→c)| dB (strong phase difference between A(b→u) and A(b→c)) determined experimentally from data b→c b→u Hadronic parameters Giri, Grossman, Soffer, Zupan, PRD 68, 054018 (2003); b→c b→u Bondar, unpublished. 4 ICHEP 2010, Paris Fernando Martinez Vidal

  7. γ from B→DK decays Dalitz plot method No D-mixing nor CPV Decay amplitude Interference terms in decay rates proportional to Fit for x± and y± for each B decay mode b→c b→u Relative weak phase g changes sign b→c b→u 5 ICHEP 2010, Paris Fernando Martinez Vidal

  8. γ from B→DK decays Dalitz plot method No D-mixing nor CPV Decay amplitude K0sρ K0sρ CF K*(892)+π- DCS K*(892)+π- Large interference in some regions of the Dalitz plot, e.g. D0→KSr D0→K*-p+ vsD0→K*+p- b→c b→u K0sρ K0sρ DCS K*(892)+π- CF K*(892)+π- b→c b→u 6 ICHEP 2010, Paris Fernando Martinez Vidal

  9. BB mES=√E*2beam-|pB*|2 spherical Dπ qq jet-like e+ e- e+ e- Experimental techniques • Exclusive reconstruction of multiple B decays: • B±→DK±, B±→D* [Dp0]K±, B±→D* [Dg]K±, B±→DK*± • Exploit kinematic constraints from beam energies. ΔE=EB*-E*beam • The main source of background : e+e- → qq, with q=u,d,s,c • Event shape variables combined into a linear (Fisher) or non linear (Neural Network) combination. Tagging information sometimes used ΔE signal region sidebands mES • Signal is separated from background through unbinned maximum likelihood fits to B± → D(*) K(*)± data using mES, DE and Fisher (or Neural Network) discriminant • Use large B± → D(*) p± data control samples (rB~0.01, x10 smaller than for DK) 7 ICHEP 2010, Paris Fernando Martinez Vidal

  10. γ from D Dalitz plot method • BaBar analysis based on complete data sample (468 M BB pairs) • Reconstruct B±→DK±, B±→D* [Dp0]K±, B±→D* [Dg]K±,and B±→DK*± final states with D→KSπ+π-, KSK+K-(eight different final states for each B charge) arXiv:1005.1096. Sub. to Phys. Rev. Lett. Only BaBar B±→DK± All components Continuum + BB BG Continuum + BB + Dp BG • Efficiencies improved substantially (20% to 40% relative) with respect to previous BaBar measurement (383 M BB) • Reprocessed data set with improved track reconstruction • Improved particle identification • Revised KS selection criteria: negligible background from D→p+p-h+h- and B→Da1(1260) PRD78, 034023 (2008) 8 ICHEP 2010, Paris Fernando Martinez Vidal

  11. D→KSp+p-,KSK+K- amplitude analysis arXiv:1004.5053. Accepted by Phys. Rev. Lett. • Extract D0 amplitude from an independent analysis of flavor tagged D0 mesons (D*+→D0π +) • Experimental analysis using complete data sample benefits from synergy with D-mixing analysis • Model determined without (reference) and with D-mixing • Fit for amplitudes relative to CP eigenstates [KSr(770) and KSa0(980)] and assume no direct CPV See Matt Bellis talk in this session for more details Parameterization Wave Parameterization Wave ππ S-wave Kπ S-wave ππ P-wave Kπ P-wave ππ D-wave Kπ D-wave K-matrix K-matrix (LASS-like) BW: ω(782), G.S ρ(770) BW: CA and DCS K*(892), CA K*(1680) BW f2(1270)0 BW CA and DCS K2*(1430) K±Ks S-wave K+K- S-wave K+K- P-wave K+K- D-wave Main differences with Belle BW: CA and DCS a0(980), CA a0(1450) Flattea0 (980), BWa0(1450) and f0(1370) BW Φ(1020) BW f2(1270)0 Good fit quality (c2/ndof) taking into account statistical, experimental and model uncertainties 9 ICHEP 2010, Paris Fernando Martinez Vidal

  12. γ from D Dalitz plot method • CP violation parameters are extracted from simultaneous unbinned maximum likelihood fit to B± → D(*) K(*)± data using mES,DE, Fisher and the Dalitz plot distributions (s+,s-) arXiv:1005.1096. Sub. to Phys. Rev. Lett. B-→DK- B-→D*K- B+→D*K+ B-→DK- B+→DK+ B+→DK+ B-→DK*- B+→DK*+ Differences between B+ and B- gives information on g 10 ICHEP 2010, Paris Fernando Martinez Vidal

  13. γ from D Dalitz plot method • Use frequentist method to obtain the (common) weak phase g and the hadronic parameters rB, dB (different for each B decay channel) from 12 (x,y) observables arXiv:1005.1096. Sub. to Phys. Rev. Lett. Our previous result: stat syst model 3.5s significance of CPV [Error on g scales roughly as 1/rB] • Smaller stat error due to additional data + improved reconstruction + slightly higher rB(DK) • Model error benefited from overlap with D-mixing analysis (e.g. reduction of experimental uncertainties inherent to the model uncertainty) 11 ICHEP 2010, Paris Fernando Martinez Vidal

  14. γ from ADS method arXiv:1006.4241. Sub. to Phys. Rev. D • Update with final data sample (468 M BB pairs). Previous analysis used 232 M BB pairs • Reconstruct B±→DK±, B±→D* [Dp0]K±, • and B±→D* [Dg]K±,with • D→K±π-(“same sign”) • D→K-p±(“opposite sign”) PRD72, 032004 (2005) + “opposite sign” + “Maximizes” CP asymmetry since “equalizes” the magnitudes of the interfering amplitudes B±→DK± First sign of an ADS signal in B± → DK± (2.1s) and B± → D* K± (2.2s) 2.1s 12 ICHEP 2010, Paris Fernando Martinez Vidal

  15. γ from ADS method arXiv:1006.4241. Sub. to Phys. Rev. D • Fit directly observables RADS and B± “same sign” yields to reconstruct the ADS asymmetry Good sensitivity to rB B+→DK+ B-→DK- 13 ICHEP 2010, Paris Fernando Martinez Vidal

  16. A(D0→ K-π+) |A(D0→ K-π+)| δD = arg[ ] rD = |A(D0→ K-π+)| A(D0→ K-π+) γ from ADS method arXiv:1006.4241. Sub. to Phys. Rev. D • Use frequentist interpretation (similar to Dalitz plot method) to obtain weak phase g and hadronic parameters rB, dB from RADS(*) and AADS(*) observables Inputs: (HFAG) +11.4 -12.4 δD = (201.9 )ᵒ rD= (5.78 ± 0.08)% (HFAG, CLEOc) (CLEOc) BaBar Dalitz plot method 14 ICHEP 2010, Paris Fernando Martinez Vidal

  17. γ from GLW method arXiv:1007.0504. Sub. to Phys. Rev. D PRD77, 111102 (2008) • Update with final data sample (468 M BB pairs). Previous analysis used 383 M BB pairs • Reconstruct B±→DK± final states with D→K+K-,π+π-(CP even) and D→KSp0,KSw,KSf (CP odd) (five different final states for each B charge) • Efficiencies improved substantially (40% to 60% relative) with respect to previous measurement • Reprocessed data set with improved track reconstruction • Improved particle identification • Introduce Fisher discriminant in the fit rather than apply cut on event shape variables B-→DK- All components Continuum + BB BG Continuum + BB + Dp BG 15 ICHEP 2010, Paris Fernando Martinez Vidal

  18. γ from GLW method arXiv:1007.0504. Sub. to Phys. Rev. D • Extract signal yields fitting directly to observables R±K/p , RK/p, and ACP± 3.6s significance of CPV in B±→DK± from ACP+ 16 ICHEP 2010, Paris Fernando Martinez Vidal

  19. γ from GLW method arXiv:1007.0504. Sub. to Phys. Rev. D • Extract signal yields fitting directly to observables R±K/p , RK/p, and ACP± 3.6s significance of CPV in B±→DK± from ACP+ Consistent with and of similar precision to Dalitz results [Dalitz results] 16 ICHEP 2010, Paris Fernando Martinez Vidal

  20. γ from GLW method arXiv:1007.0504. Sub. to Phys. Rev. D • Extract signal yields fitting directly to observables R±K/p , RK/p, and ACP± 3.6s significance of CPV in B±→DK± from ACP+ Dalitz 16 ICHEP 2010, Paris Fernando Martinez Vidal

  21. γ from GLW method arXiv:1007.0504. Sub. to Phys. Rev. D • Extract signal yields fitting directly to observables R±K/p , RK/p, and ACP± 3.6s significance of CPV in B±→DK± from ACP+ Dalitz+GLW 4.4s significance of CPV in B±→DK± 16 ICHEP 2010, Paris Fernando Martinez Vidal

  22. γ from GLW method arXiv:1007.0504. Sub. to Phys. Rev. D • Use frequentist interpretation (similar to Dalitz plot method) to obtain weak phase g and hadronic parameters rB, dB from RCP± and ACP± observables Weak sensitivity to rB BaBar Dalitz plot method 17 6 ICHEP 2010, Paris Fernando Martinez Vidal Fernando Martinez Vidal

  23. Summary and outlook • Recent progress on g, the hardest UT angle to measure • BaBar Dalitz plot method approach drives the measurement and benefited from synergy with D-mixing analysis (e.g. reduction of experimental uncertainties inherent to the model uncertainty) (see Matt Bellis talk later in this session) • First sign of an ADS signal in B± → DK± and B± → D* K± • Compelling evidence of direct CPV in B± → D(*)K(*)± decays stat syst model 3.5s significance of CPV, B± → D(*)K(*)± combined, Dalitz only 3.6s significance of CPV, B± → DK± only, GLW only 18 ICHEP 2010, Paris Fernando Martinez Vidal

  24. Summary and outlook • Recent progress on g, the hardest UT angle to measure • BaBar Dalitz plot method approach drives the measurement and benefited from synergy with D-mixing analysis (e.g. reduction of experimental uncertainties inherent to the model uncertainty) (see Matt Bellis talk later in this session) • First sign of an ADS signal in B± → DK± and B± → D* K± • Compelling evidence of direct CPV in B± → D(*)K(*)± decays 4.4ssignificance of CPV in B±→DK± only, Dalitz+GLW combined 18 ICHEP 2010, Paris Fernando Martinez Vidal

  25. Summary and outlook • Recent progress on g, the hardest UT angle to measure • BaBar Dalitz plot method approach drives the measurement and benefited from synergy with D-mixing analysis (e.g. reduction of experimental uncertainties inherent to the model uncertainty) (see Matt Bellis talk later in this session) • First sign of an ADS signal in B± → DK± and B± → D* K± • Compelling evidence of direct CPV in B± → D(*)K(*)± decays Experiments providing most of analyses today 3.1 GeV e+ 9 GeV e– 468M BB pairs 3.5 GeV e+ 8 GeV e– 657M BB pairs ~10-15o Experiments that can also give results in near future • Close to “last word” from BaBar (~10-15o error) • Still statistics limited, even with full data sets • BaBar “legacy” g average from GLW, ADS and Dalitz plot methods in progress ~2-3o Planned facilities • Need to reduce the error in order to see possible deviations <1o 18 ICHEP 2010, Paris Fernando Martinez Vidal

  26. Backup

  27. BaBar detector and data sample Deliveredluminosity Recorded luminosity RecordedΥ(4S): 432 fb-1 RecordedΥ(3S): 30.2 fb-1 RecordedΥ(2S): 14.5 fb-1 Off peak Instrumented Flux return (Muon and hadron reco.) 3.1GeV e+ Magnet (1.5 T) Υ(3S) e- Υ(2S) 9GeV Υ(4S) Detector of Internally Reflected Cherenkov (PID, Kaon separation from pions) Drift Chamber (Main tracking system) Electromagnetic Calorimeter (Detection of neutral particles) • BaBar data taking ended on 7th April 2008 • BaBar recorded 470M BBat Υ(4S) Silicon Vertex Tracker (Tracking at low momentum and vertex reconstruction)

  28. γ from D Dalitz plot method • Signal yields as used in the final fit for CP parameters • Efficiencies improved substantially (20% to 40% relative) with respect to previous BaBar measurement (383 M BB) • Reprocessed data set with improved track reconstruction • Improved particle identification • Revised KS selection criteria: negligible background from D→p+p-h+h- and B→Da1(1260) arXiv:1005.1096. Sub. to Phys. Rev. Lett. PRD81, 112002 (2010) PRD78, 034023 (2008)

  29. D→KSp+p-,KSK+K- amplitude analysis arXiv:1004.5053. Accepted by Phys. Rev. Lett. • Extract D0 amplitude from an independent analysis of flavor tagged D0 mesons (D*+→D0π +) • Experimental analysis using complete data sample benefits from synergy with D-mixing analysis • Model determined without (reference) and with D-mixing • Fit for amplitudes relative to CP eigenstates [KSr(770) and KSa0(980)] and assume no direct CPV 540 800±800 79 900±300 See Matt Bellis talk in this session for more details

  30. γ from D Dalitz plot method • CP violation parameters are extracted from simultaneous unbinned maximum likelihood fit to B± → D(*) K(*)± data using mES,DE, Fisher and the Dalitz plot distributions (s+,s-) arXiv:1005.1096. Sub. to Phys. Rev. Lett. B-→DK- B+→DK+ Most precise measurement of (x,y) Consistent results with latest Belle results PRD81, 112002 (2010) ICHEP 2010, Paris

  31. γ from D Dalitz plot method arXiv:1005.1096. Sub. to Phys. Rev. Lett.

  32. γ from D Dalitz plot method arXiv:1005.1096. Sub. to Phys. Rev. Lett.

  33. Other hadronic parameters relevant for g • Updated search for B+→D+K0 and B+→D+K*0 • Can only proceed through annihilation or rescattering • Allows an estimation of rB0 for B0 from rB for B+ needed for • B0→D0K0 measures rB0sin(2b+g) in time-dependent asymmetry • B0→D0K*0 measures g in direct CPV (similar to B+) • BaBar analysis with full data sample: 468 M BB • No evidence for signals arXiv:1005.0068. Submitted to PRD

  34. BaBar vs WA Courtesy of V. Tisserand and the CKM fitter group

  35. Backup

  36. CKM angle g • The electroweak coupling strength of W± to quarks described by the CKM matrix d s b u Wolfenstein parameterization l~0.22 A~0.8 r~0.16 h~0.34 c t Unitarity condition from 1st and 3rd columns • Overconstraint apex coordinates • CP violation measurements give angles • Semileptonic decay rates (and other methods) give sides • Precise measurement of SM parameters • Search for NP in discrepancies of redundant measurements

  37. CKM angle g

  38. γ from B→DK decays GLW-like method No D-mixing nor CPV Decay amplitude K0sρ K0sρ π+ π- CP-even K- K+ b→c b→u GLW K0sπ0 K0sω CP-odd K0sΦ K0sρ K0sρ K0sρ Large interferences in some Dalitz plot regions Strong phases varying over the Dalitz plane b→c b→u Gronau, London, Wyler, PLB 253, 483 (1991); PLB 265, 172 (1991)

  39. γ from B→DK decays ADS-like method No D-mixing nor CPV Decay amplitude CF K*(892)+π- DCS K*(892)+π- K+π- b→c b→u K+π-π0 ADS K+π-π+π- DCS K*(892)+π- CF K*(892)+π- Large interferences in some Dalitz plot regions Strong phases varying over the Dalitz plane b→c b→u Atwood, Dunietz, Soni, PRL 78, 3357 (1997)

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