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Determination of the angles of the unitarity triangle at B A B AR

Hadron`07, Frascati October 12, 2007. Determination of the angles of the unitarity triangle at B A B AR. Sandrine Emery. Outline. New!. = Summer 2007. Physics motivation Methodology B A B AR analyses & results: b a g. All unpublished results are preliminary. Difficulty.

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Determination of the angles of the unitarity triangle at B A B AR

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  1. Hadron`07, Frascati October 12, 2007 Determination of the angles of the unitarity triangle at BABAR Sandrine Emery BABAR- Unitarity angles

  2. Outline New! = Summer 2007 • Physics motivation • Methodology • BABAR analyses & results: • b • a • g All unpublished results are preliminary Difficulty BABAR- Unitarity angles

  3. In Standard Model: due tocomplex CKM unitary matrix Wolfenstein parameterization: with l 0.22 , A  0.83 CP violation if h ≠ 0. CP violation BABAR- Unitarity angles

  4. The unitarity triangle g = phase of Vub (b→u transition) b = phase of Vtd (B0-B0 mixing) • = p-b-g process involving both B0 mixing and b→u transition (r,h) Apex of triangle h a(f2) g(f3) b(f1) r (0,0) (0,1) BABAR- Unitarity angles

  5. CP violation in the interference between mixing and decay B0 Mixing CP final state B0 fCP Time-dependent CP asymmetry S 0 : Indirect CP violation C 0 : Direct CP violation Mixing BABAR- Unitarity angles

  6. Time-dependent CP asymmetry If only one diagram involved in B0 fCP decay, no direct CP violation: 0 (ex: b c): sin2b measurement g (ex: b  u): sin2a measurement is the CKM phase in For processes involving tree b u tree, penguin diagrams are also involved Penguin Diagram Tree Diagram Vtd * Vub Dependence on  Dependence on  BABAR- Unitarity angles

  7. ( ) CP Asymmetry Measurement t =0 fully reconstructed B0 Dz= Dtgbc Coherent B0B0 production • Exclusive B0 meson reconstruction. • Time measurement:Dz ≈ 250 mm, s Dz ≈ 170 mm. • B-flavor tagging: Q = Se(1-2w)2≈ 30%. withe efficiencyandwmistag rate. B0 B0 For b: J/YK0S,L,.. For a: p+p-, r+r-,ppp, … (4S) B0 tag l- (e-, m-) BABAR- Unitarity angles

  8. Signal Selection • Hadron ID separation p/K • Kinematical identification with • Beam energy substituted mass • Energy difference • Event-shape variables combined in a neural network or Fisher discriminant to suppress jet-like continuum events ‘Spherical’ Jet-like qq BB BABAR- Unitarity angles

  9. Measurements of b * B0 B0 h a(f2) g(f3) b(f1) r (0,0) (0,1) BABAR- Unitarity angles

  10. B0 charmonium K0: bccs (gold) No CKM phase 383M BB hep-ex/0703021 f=-1 CP eigenvalue=-1(KS),+1(KL) f=1 BF ≈10-3 (color suppressed) Other diagrams negligible SM expectation:S = -f sin2bC≈0 BABAR- Unitarity angles

  11. cos2b constraints To solve the sin2b p-2b ambiguity • J/Y K* • cos2b =3.32 +0.76 −0.96 ± 0.27 PRD 71, 032005 (2005) • D*D*Ks • cos2b > 0 @94% c.l. Phys.Rev. D74 (2006) 091101 • Bd D0(Ksp+p-) h0arXiv: 0708.1544 • cos2b > 0 @86% c.l. New! Preliminary BABAR- Unitarity angles

  12. New! Preliminary cos(2) with B0 D(*)0h0 bcud color-suppressed tree diagram h0=p0,h, h’,w Time-dependent Dalitz analysis of (interference D0 D0) sensitive to sin2β and cos2β Preliminary D0 Dalitz plot 335±32 signal events Bondar, Gershon and KrokovnyarXiv:hep-ph/0503174 383M BB arXiv:0708.1544 BABAR- Unitarity angles

  13. sin2beff sin2b expected in SM but New Physics would lead to a different result s q q Measuring sin(2) in B0 D(*)+ D(*)- NP particle can enter in loop D(*)- D(*)- B0  B0 D(*)+ D(*)+ ~2-10% in SM but sensitive to NP • No evidence of direct CP violation and sin2b consistent with charmonium in both B0D+D- (PRL, 99 071801 (2007)) and • B0D*+D*- (arXiv:0708.1549, NEW) analyses using 383M BB. Preliminary Measuring sin(2) in B0D(*)0 h0 with D0CP Recent published result (PRL 99, 081801 (2007) ) with 383M BB Measuring sin(2) in bsqq penguin modes Updates in several penguin modes last summer BABAR- Unitarity angles

  14. New! CP Asymmetries in B0K0S+- Dalitz plot projection on m(+-) Time-dependent Dalitz analysis • Contributions from K*-(892), K*- (1430), f0(980), 0(770), Non-Resonant • Fit phase and magnitude for each component’s amplitude • Derive quasi-2-body parameters C, S and ACP. 2172 ± 70 signal events m(p+p-)[GeV/c2] Preliminary CP asymmetry in KSf0 region Sample enhanced in signal with cut on likelihood ratio 383M BB arXiv:0708.2097 Preliminary Dt (ps) BABAR- Unitarity angles

  15.  New/Updated BaBar/BelleResult sin2 gold BABAR Preliminary     New naïve world HFAGaverage <1 from the naïve golden mode sin2 value (2.5 s last winter)       But bad global c2 =32/16 dof (CL =0.01)     HFAG recommands extreme caution regarding naive averages   BABAR- Unitarity angles

  16. a= p-b-g process involving both B0 mixing and b→u transition Measurements of a g = phase of Vub (b→u transition) b = phase of Vtd (B0-B0 mixing) p- or r- Or p+p-p0 p+ or r+ h a(f2) g(f3) b(f1) r (0,0) (0,1) BABAR- Unitarity angles

  17. 2|k|=2|-eff| q q Constrains a-aeff Isospin analysis Time dependentp+p- or r+r-CP asymmetry allows to measure sin2aeff. Use SU(2) (u and d quarks) to relate amplitudes of allpp (rr) modes. ~ for charge conjugate reaction For B000, S00 measurement constrains this angle 4-fold ambiguity k=±(q±q) If only the BRs are measured (pure tree) Neglect EW penguins Gronau, London : PRL65, 3381 (1990) BABAR- Unitarity angles

  18. Measurement of  with B  decays B0 p+p- NEW Isospin analysis using BF for +-, +0 and 00 and CP parameters C+-, S+- C00 “Large” BR for B0  00 (penguin contamination) B0 tag 1139±49 signal events Preliminary B0 tag 383M BB arXiv: 0707.2798 Background subtracted with sPlot technique 383M BB PRL 99, 021603 (2007) New! Preliminary 227M BB PRD 75, 012008 (2007) BABAR- Unitarity angles

  19. Measuring α with B0-+decays 729±60 signal events Analysis more difficult: • 2 π0 in the final state. • Wide  resonances. • V-V decay: L=0,1,2 partial waves : Longitudinal: CP-even state. Transverse: Mixed CP states. • Analysis based on  polarization. Eventually a very efficient mode: • BF~ 5 times larger than for B→ ππ. • Penguin much smaller than in ππ. •  are ~100% longitudinally polarized. • Almost a pure CP-even state! B0 tag B0 tag Sample enhanced in signal Helicity Frame 383M BB PRD 76 052007 (2007) BABAR- Unitarity angles

  20. New rr isospin analysis Nsig=85±27±17 Time Dependent CP r0r0 arXiv:0708.1630v1 106×BF= 0.84 ± 0.29 ± 0.17 fL= 0.70 ± 0.14 ± 0.05 SCP= 0.5 ± 0.9 ± 0.2 CCP= 0.4 ± 0.9 ± 0.2 427 106 BB New! Preliminary Preliminary New! Preliminary PRD 76, 052007 (2007) 383 106 BB |a-aeff|<=16.5 deg. @ 90% c.l. PRL 97, 261601 (2006) 232 106 BB BABAR- Unitarity angles

  21. +– 00 –+ Dalitz analysis of B0 (rp)0  p+p-p0 •  Dominant decay B0 r+p- : not a CP eigenstate •  Isospin analysis not viable, too many amplitudes • B0 r+p-, B0 r-p+, B0 r0p0, B+ r+p0, B+ r0p+and charge conjugates •  Better approach:Time-dependentDalitz analysis • Simultaneous fit of aand T, P amplitudes • aconstrained with no ambiguity (unlike sin(2a) measurement) Snyder-Quinn, PRD 48, 2139(1993) Amplitude A(B3p) dominated by r+,r-and r0 resonances r 0 p- p0 375 106 BB BABAR PRD 76 (2007) 012004 m2(p-p0) p+  r - p- p0 p+ BABAR- Unitarity angles m2(p+p0)

  22. Summary onα http://ckmfitter.in2p3.fr Preliminary ! For pp: extra theoretical assumptions hep-ph/0701204 1-C.L. a[°] rr: best single measurement rp: disfavors rr mirror solutions a[°] Promising new mode: a1p High BR = (33.2 ± 3.8 ± 3.2) 10-6 PRL 98, 181803 (2007) Use SU(3) symmetry (K and a1K1) and BK1 and B a1K decays to constrain a-aeff Gronau and Zupan, PRD 73, 057502 (2006) BABAR- Unitarity angles

  23. Measurements of g Colour suppressed bu D0 B- K-  K- h B- D0 a(f2) g(f3) b(f1) r (0,0) (0,1) Can also measure 2+ via TDCPV in B0D+-,+ (r-,+) 232M BB PRD71, 112003 (2005) 232M BB PRD73, 111101 (2006) BABAR- Unitarity angles

  24. New! 382M BB arXiv: 0708.1534 B±DCPK ±GLW update GLW Gronau, London (1991),Gronau, Wyler (1990) Preliminary Ratio of BFs D0 decays to CP± final States: • KK,  (CP=+1),K00, K0 (CP=-1) 4 observables: • 2 CP asymmetries and 2 ratios of BFs 3 unknowns : • Strong phase B, rBand  CP asymmetries rB A(bu)/A(bc) ~ 0.1-0.3 B: strong phase difference Preliminary 85 ± 14 signal events 177 ± 20 signal events Evidence (3.4) for direct CP violation BABAR- Unitarity angles

  25. GLW,ADS, GGSZ GLW method → fCP ADS method → K-p + → fCP → Ksp+p- GGZS method → K-p + GLW Gronau, London (1991),Gronau, Wyler (1990) ADS  Atwood, Danietz, Soni (1997) GGSZ Giri, Grossman, Soffer, Zupan (2003) → Ksp+p- GLW:arXiv: 0708.1534 -382M BB Small interference, but hadronic unknowns from D(*)0 decay cancel out ADS: Larger interference between more comparable amplitudes: bu ; regular D Kp decay bc ; doubly cabibbo suppressed D Kp But D decay hadronic uncertainties GGZS: Best method. Dalitz analysis. Preliminary BABAR- Unitarity angles

  26. Conclusion Consistent results between the measurements of the angles (,  and ) and other CKM constraints (Unitarity Triangle sides (md, ms, |Vub|….), eK,etc.) world All CKM constraints Angles only BABAR- Unitarity angles

  27. BACK-UP SLIDES BABAR- Unitarity angles

  28. CP violation in the interference between mixing and decay B0 B0 mixing Mixing (q/p) CP final state B0 fCP phase 2b Time-dependent CP asymmetry S 0 : Indirect CP violation C 0 : Direct CP violation ~e-i2b BABAR- Unitarity angles

  29. Amplitude analyses • Use kinematics at BB threshold (mES, DE) • Fight combinatorial (mainly continuum with MVA) and peaking backgrounds. • Can use Dt and tagging information, TDCPA analyses • Isobar expansion to model amplitude for B(bar)3bodies with a non resonant term and resonances. • Each term is a complex amplitude multiplied by a complex (isobar coefficient) whose argument incorporates the CKM phase. • Extended UML fits to the isobar coefficients and yields • Misreconstructed signal events included BABAR- Unitarity angles

  30. Measuring sin(2) in B0 D(*)+ D(*)- 383M BB PRL, 99 071801 (2007) Two decay amplitudes interfere • bc tree diagram with CPS=sin2β • bc penguin diagram with S~0  Small contribution ~2-10% in SM  Sensitive to NP B0D+D- No Direct CPV 131±14 signal events 638±38 signal events CP Violation in B0D+D- CP Violation in B0D*+D*- Vector-Vector final state (not a pure CP eigenstate)  CP is determined using D* decay angles (transversity analysis) B0D*+D*- New! 383M BB arXiv:0708.1549 Both consistent with sin2β in charmonium and no evidence of direct CP violation BABAR- Unitarity angles

  31. β in B0K0S+- Time-dependent Dalitz  Q2B • Fit of the phase and magnitude of the amplitude of each component • Quasi-2-body parameters C, S and ACP are derived from them with the physical boundary S2+C2<1. • S(K0Sf0) close to physical boundary  non-Gaussian uncertainty m(K0Sp+) [GeV/c2] Dalitz plot projections m(p+p-) [GeV/c2] BABAR- Unitarity angles

  32. Case of B0→p+p-or B0→r+r- Tree decay Penguin decay pollution  phase g d = strong phase difference between penguin and tree Tree + Penguin Tree only aeffective only BABAR- Unitarity angles

  33. h- h+ h0 h0 h- h0 h0 h+ h- h- h0 h0 Tree Penguin color-suppressed  small Isospin=2 final state forB+p+p0 Forbidden for penguins Almost true forB+r+r0 Vub Phase g Falk, Ligeti, Nir, Quinn hep-ph/0310242 BABAR- Unitarity angles

  34. p0 p0 r- r+ p- p+ B0 r+r-analysis 3 amplitudes (VV decay): A0 (CP-even longitudinal), fraction fL A|| (CP-even transverse),A┴ (CP-odd transverse). BABAR- Unitarity angles

  35. ( ) ( ) B0 →p+p-p0results 375 106 BB k,l {+,0,-} T tree P penguin BABAR PRD 76 (2007) 012004 Likelihood scan of a: rrmirror solution A(B03p) : functions of the Akl and well-known kinematics functions of the Dalitz variables m2(p+p0) and m2(p+p0) 1-C.L. ( ) • A(B03p) Time-dependent analysis: • Disentangles: • One constant term • One sin(Dmt) term • One cos(Dmt) term • Providing enough contraints on a and tree and penguin amplitudes Weaker constraint than rr but rr mirror solutions disfavored BABAR- Unitarity angles

  36. from b → uu-bar d Belle -BABAR comparison PRL 99 (2007) 021603 PRL 98 (2007) 211801 preliminary arXiv:0705.2157 PRD 76 (2007) 011104 PRD 76 (2007) 012004 PRL 98 (2007) 221602 BABAR- Unitarity angles

  37. B0 a1 B0 tag New approach for  :Ba1/K1/ a1K B0 tag • B a1 decay: same quark diagram as B// • Use SU(3) symmetry (K and a1K1) to extract information from BK1 and B a1K decays. Gronau, Zupan, PRD 73, 057502 (2006) • First bounds on - eff are coming • Possible direct constraint on  with Bb1K…. 608±53 signal events 383M BB PRL 98, 181803 (2007) BABAR- Unitarity angles

  38. Different treatment of the pp results to constrain a Preliminary! http://ckmfitter.in2p3.fr • Significantly non-zero S in B→hh=contradiction with • having a finite probability for alpha at zero (flat triangle signifying no CPV) • discovery of CP violation in that mode • S=0→a≠ 0. • Additional information from SU(3) tells the • minimiser that really large penguins are unphysical, so the solution very near zero is unphysical. Bayesian approach With SU(3) constraints Frequentist approach with/ without SU(3) constraints (shaded) BABAR arXiv: 0707.2798 hep-ph/0701204 BABAR- Unitarity angles

  39. Combined D* partial+full reco. 68% CL 90% CL Sin(2β+) with B0D(*)±±/± Vub Dependence on  • CP violation stems from interference between these two decays through (B0,B̅0) mixing. • Time –dependant asymmetry to measure sin(2+). • Two complementary approaches : • Full reconstruction of D, D and D*. • Partial reconstruction for D* only. 232M BB PRD71, 112003 (2005) 232M BB PRD73, 111101 (2006) |sin(2b+g)|>0.64 @68% CL BABAR- Unitarity angles

  40.  with GGSZ method • Use interference in Dalitz plot BD(*)0(D0)K decay • Sensitive to rB(*), strong phases B(*)and the CKM phase . • 4x2 (D/D*)quantities are measured: • With a frequentist approach, constraints are derived on rB(*) and  • Error on  strongly correlated with r value!!! • Update of this analysis coming soon D0KS+ - Use flavor tagged D from D*±(KS+ -)± 347M BB hep-ex/0607104 B-D0(D0)K- B+D0(D0)K+ BABAR- Unitarity angles

  41. BABAR- Unitarity angles

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