david brown lawrence berkeley national lab babar collaboration n.
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  1. David Brown Lawrence Berkeley National Lab BaBar Collaboration CKM phase and CP Violation in B Decays August 14, 2007 Daegu, Korea

  2. Talk Outline • Review of CPV in the B system • Results on the CKM unitarity angle =1 • Results on the CKM unitarity angle =2 • Results on the CKM unitarity angle =3 • Results on the Bs phase angle s • Results on Direct CPV • Conclusions I will concentrate on (some) New Results D. Brown, CKM phase and CP Violation in B Decays

  3. Quark-Sector Flavor in the SM • 3 known generations of quark doublets • (u,d) (c,s) (t,b), EM charge (2/3, -1/3) • Origin of families unknown in SM • Only the charged-current EW interaction can change flavor in the SM • EW eigenstates aren’t mass eigenstates • Only SM connection between generations! VCKM D. Brown, CKM phase and CP Violation in B Decays

  4. Vud Vus Vub Vcd Vcs Vcb Vtd Vts Vtb 1-2  A 3(-i) - 1- 2/2A 2 A3(1- -i) -A 2 1 The CKM matrix • Relates EW flavor and quark mass eigenstates • No prediction of values within SM • 3 generations, Unitarity  3 rotations, 1 phase • Non-zero phase implies CPV in flavor transitions • New Physics (NP) with non-SM flavor couplings would make the CKM description incomplete • Eg: 4th generation, SUSY, … Wolfenstein parameterization = + O(4) VCKM = ≈0.23, A≈0.8,≈0.2, ≈0.4 D. Brown, CKM phase and CP Violation in B Decays

  5. The Unitarity Triangle(s) • Graphical expression of unitarity condition(s) • 1 triangle has roughly equal-length sides • CKM Unitarity violation would imply New Physics • Test SM + CKM by over-constraining angles and sides (r h)  -i a g b  (,0) (1,0) D. Brown, CKM phase and CP Violation in B Decays

  6. Consequences of CPV • CPV can occur when B F, F amplitudes interfere • CPV in decay (direct CPV) • CPV in mixing (original CPV seen in KS, KL) • Very small for B system (exp. limit <10-2, predicted ~10-3 in SM) • CPV in mixing + decay (indirect CPV) • B system uniquely situated for CPV studies • Mixing, long lifetime, large production X-section, rich decay set, heavy quarkstheoretically accessible, … Mixing+Decay CPV Direct CPV B0 and B   B0 B0 e-2i  CP  S1† EW1 AF 0 AF EW1† S2† EW2 decay S1 S2 decay EW2†   FCP †≠ D. Brown, CKM phase and CP Violation in B Decays

  7. Detecting Indirect CPV in B-decays B0(b) e- Flavor tagging Q≈30% at B-factories ≈few % at Tevatron K- B-factories Coherent evolution e- e+ m+ (4S) mixing BfCPexclusive reconstruction ~10% p+ Tevatron PPBB+Xhad Dz≈bgct p- m- incoherent D. Brown, CKM phase and CP Violation in B Decays

  8. The B-factories • Asymmetric e+e- colliders make boosted (4S) • cB~200 m in the lab frame • General-purpose detectors • Tracking EM calorimetery, muon system, PID,… • BaBar/PEP-II Total Sample ≈ 450 fb-1 • KEK-B/Belle Total Sample ≈ 700 fb-1 • Data sets have increased ~10% in the last year • Many new results from data ‘backlog’! • Tevatron Run2 results on ≥1fb-1 coming out now D. Brown, CKM phase and CP Violation in B Decays

  9. Beta B0 B0 (r h) h a g b r (,0) (1,0) D. Brown, CKM phase and CP Violation in B Decays

  10. B0 charmonium K0:bccs f= CP eigenvalue = -1(KS),+1(KL) No EW phase • SM decay dominated by a single tree diagram • Leading order (Tree) diagram has no weak phase • asymmetry directly measures  • Higher-order diagrams are smaller by factor ~O(10-210-3) • most have same EW phase • BF ≈10-3 (color suppressed) • SM expectation: S = -f sin2bC≈0 D. Brown, CKM phase and CP Violation in B Decays

  11. B0 charmonium K0: bccs NBB = 535M Nsig = 7484±87 NBB = 383M Nsig = 4748 Purity=55% background PRL 98, 031802 (2007) hep-ex/0703021 MB (GeV/c2) background • Easily reconstructed final states • Charmonium l+l- has high efficiency, low background • KS+- easily recognized in tracking detectors • Strong kinematic variables separate B from background • MB constrained to known beam energies to improve resolution • EEB-Ebeam is an independent kinematic variable D. Brown, CKM phase and CP Violation in B Decays

  12. sin2b in B0→ charmonium K0 : bccs NBB = 383M J/KS NBB = 535M B0 tags B0 tags J/KL background PRL 98, 031802 (2007) BaBar Preliminary (hep-ex/0703021) t (ps) ft (ps) D. Brown, CKM phase and CP Violation in B Decays

  13. b from B0→ charmonium K0 : bccs Sf = sin2 95%CL contours Sin2=0.678±0.026 New world average 2-fold ambiguity resolved by several cos2 measurements Sets the gold standard for CPV measurements B0 → D03-bodyh0 Dalitz Analysis (BaBar) B0 → KS+- Dalitz Analysis (BaBar) B0 → KSK+K- Dalitz Analysis (BaBar) new + older results on B0 → J/K*, … D. Brown, CKM phase and CP Violation in B Decays

  14. B0→ J/0: b → ccd • Enhanced sensitivity to higher-order (penguin) diagrams • Cross-check on assumption that Cgold≈0 NP particle can enter in loop  M.Ciuchini,M.PieriniandL.Silvestrini,Phys.Rev.Lett95,221804(2005) C NBB = 535M S=−0.65 ± 0.21± 0.05 C= -0.08 ± 0.16 ± 0.05 290 J/ψπ0 candidates Purity=88±7% (0,0) hep-ex/0708.0304 (submitted to PRD.RC) MB (GeV/c2) S D. Brown, CKM phase and CP Violation in B Decays

  15. B0 → D+D- : b → ccd D- D- B0  D+ B0 D+ • Two decay amplitudes interfere • b → c tree diagram with S = -sin2b • b → d penguin diagram with S ~ 0 • Penguin is expected to be small • ~2-10% (PRD 61, 014010, 2001) • Larger backgrounds Standard Model predicts: Y. Grossman and M. Worah, Phys. Lett. B 395, 241 (1997) D. Brown, CKM phase and CP Violation in B Decays

  16. S and C in B0 → D+D- : b → ccd C B0 tags (0,0) Belleclaims evidence for direct CP violation at 3.2 s NBB = 383M Nsig =131±14 B0 tags NBB = 535M Nsig =128±14 background S CCP(B0D+D-) = -0.91 ± 023 ± 0.06 CCP(B0D+D-) = +0.11± 022 ± 0.07 hep-ex/0702031 PRL 98,221802(2007) New Belle Result: Agreement on C has CL=0.003 ⇒ >3.0σ discrepancy ACP(B+D+D0) = 0.01 ± 0.08 ± 0.02 Preliminary BELLE-CONF-0762 D. Brown, CKM phase and CP Violation in B Decays

  17. CPV in B0 → D*+D*- : b → ccd • Same diagram as B0 → D+D-,but Vector-Vector final state • f (CP) depends on helicity, analyzed using D* decay angles BaBar preliminary NBB = 383M Nsig =617±33 background hep-ex/0708.1549 D. Brown, CKM phase and CP Violation in B Decays

  18. S and C in b → ccd -Sf Cf sin2 Silver modes: generally good agreement with golden mode S= sin2bC=0 D. Brown, CKM phase and CP Violation in B Decays

  19. Purely Penguin decays: bsqq • No tree-level contributions • New Physics can enter at equal order as SM • SM predicts same EW phase as b → cW- • Comparison with charmonium sin2b provides a direct test for NP • Many accessible modes • NP might couple to some or all • More challenging experimentally • BF ~10-5, large backgrounds from continuum SM New Physics s  s q q q q SUSY,… D. Brown, CKM phase and CP Violation in B Decays

  20. (Spherical) (Jet-like) B0 → KS00 :bsqq LR>0.9 LR>0.9 Nsig = 307±32 LR MB(GeV/c2) DE(GeV) Preliminary S =+0.43 ± 0.49 ± 0.09 C=+0.17 ± 0.24 ± 0.06 LR>0.9, good tag B0 tags B0 tags NBB = 657M BELLE-CONF-0723 2.0 from the SM expectation S= -sin2 t (ps) t (ps) D. Brown, CKM phase and CP Violation in B Decays

  21. B0 → KS+- :bsqq • Measure TDCPA at each point on the Dalitz plot • Include interference between +-,KS± resonances • 0, f0,K*, … • Supersedes previous results on B0 → KS ,KSf0 • + Direct CPV in B0 → K*+relative phases 2 2 B0 → KSf0(980) B0 → KS(770) 2eff 2eff hep-ex/???? 2.1 > 2 from charmonium 2-fold  ambiguity (partially) resolved D. Brown, CKM phase and CP Violation in B Decays

  22. sin2b in bsqq Penguins -Sf= sin2eff sin2   New HFAGaverage X.X  from the naïve SM prediction                New/Updated BaBar/BelleResult D. Brown, CKM phase and CP Violation in B Decays

  23. (r h) h a g b r (,0) (1,0) Alpha • In principle measurable using any bu dominated B0fCP • Very rare decays! BF~10-6 • In practice, penguin modes have similar magnitude, different EW phase  extracting  is a challenge!   D. Brown, CKM phase and CP Violation in B Decays

  24. B0→ +- : buud B0tags B0 tags B0 tags NBB = 383M Nsig = 1139±39 B0 tags NBB = 535M Nsig = 1464±65 PRL 98, 211801 (2007) PRD 75 (2007) 012008 2.1 tension in C D. Brown, CKM phase and CP Violation in B Decays

  25. Extracting  from B0→ +  - • CPV well established • Problem: extract  from eff • Solution: Isospin • Measure isospin-related modes • Rates and C/ACP (if possible) • Adds another discrete ambiguity! M. Gronau and D. London, Phys Rev. Lett. 65, 3381 (1990) 9° 97 ± 11° BR(B0→ π0 π0) = (1.47 ± 0.25 ± 0.12)×10-6 C(B0 → π0 π0) = -0.49 ± 0.35 ± 0.05 BR(B± → π± π0) = (5.02 ± 0.46 ± 0.29)×10-6 A(B± → π± π0) = 0.03 ± 0.08 ± 0.01 hep-ex:0707.2798 D. Brown, CKM phase and CP Violation in B Decays

  26. B0→ a1+p: buud First TDCPV analysis of a1+p • use SU(3) to relate states • BF B0→ K1+p • BF and ACP in B0→ a1- • Next step: constrain  Large signal, significant background NBB = 383M B0 tags background B0→ K1+p B0 tags Nsig = 608 ± 53 PRL. 97, 051802 (2006) MB (GeV/c2) PRL 98 181803 αeff = 78.6°±7.3° NBB = 535M Nsig = 654 ± 70 hep-ex/0706.3279 MB (GeV/c2) D. Brown, CKM phase and CP Violation in B Decays

  27. B0→ 0 : buud TDCPV in  NBB = 535M NBB = 383M Nsig=729 ± 60 • Vector+Vector final state • Analyze helicity to separate CP admixture as in B0→ D*+D*- • Use Isospin triangle to constrain  as in  hep-ex/0705.2157 PRD76, 011104(R) (2007) t (ps) t (ps) C = 0.01 ± 0.15 ± 0.06 S = -0.17 ± 0.20 fL = 0.992 ± 0.024 D. Brown, CKM phase and CP Violation in B Decays

  28. The critical side: B0→ 0 NBB = 520M NBB = 427M Nsig = 85 ± 27 ± 17 Nsig=34±16 BaBar Preliminary MB GeV/c2 M GeV/c2 Lsig/ Lsum Preliminary signal BELLE-CONF-0747 Preliminary hep-ex/??? First TDCPV analysis of 0! D. Brown, CKM phase and CP Violation in B Decays t (ps)

  29. B0→ (0 BaBar Preliminary @68%CL Constraining using buud ° D. Brown, CKM phase and CP Violation in B Decays

  30. (r h) h a g b r (,0) (1,0) Gamma  B+,B- rate asymmetry (DCPV) is sensitive to The problem: How to distinguish EW phase from strong phase? Can also measure 2+ via TDCPV in B0D(*)+,--,+ D. Brown, CKM phase and CP Violation in B Decays

  31.  from B±D0K± • Three Answers • D0 decays to 2-body CP eigenstates (K+K-, +-,…) GLW • large + unknown asymmetry in B+,B- BFs • D0 decays to non-CP eigenstates (K+  -, K+ - 0,…) ADS • Better match in rates (Cabbio suppression enhances interference) • D0 decays to 3-body (K0S+-) GGSZ • Uses (~known) variation of resonance strong phase across Dalitz plot • Requires detailed model of resonant substructure • All methods have (varying) weakness due to unknown or under-constrained parameters •  Constrain  by combining results from all methods GLW Gronau, London (1991),Gronau, Wyler (1990) ADS  Atwood, Danietz, Soni (1997) GGSZ Giri, Grossman, Soffer, Zupan (2003) D. Brown, CKM phase and CP Violation in B Decays

  32. Combined constraint on  = 88 ± 16 ° Includes a new preliminary result: B±D0K± GLW (BaBar) ° D. Brown, CKM phase and CP Violation in B Decays

  33. The Unitarity Triangle: angles only D. Brown, CKM phase and CP Violation in B Decays

  34. The Unitarity Triangle: all constraints A consistent picture across a huge array of measurements D. Brown, CKM phase and CP Violation in B Decays

  35. BsJ/ (fs): bccs • Same quark decay as B0charmonium K0 • Bs mixing goes as Vts no CPV phase as in Bd mixing • SM prediction of fs = 4.2 ± 1.4X10-3 Hep-ph/0612167 Simultaneous fit to fs, s Consistent with SM D. Brown, CKM phase and CP Violation in B Decays

  36. Direct CPV in charmless B Decays K*0 3.8 K+0 3.0 K+- ~8 K+ 3.0 Isospin analogs AK(B+K0)=0.009 ± 0.025 AK(B+K+)=0.050 ± 0.025  AK(Bd)=−0.095 ± 0.012 (WA) Effect from EW penguins? D. Brown, CKM phase and CP Violation in B Decays

  37. Direct CPV in Bs Decays AK(Bd)=-0.086 ± 0.023 ± 0.009 3.5 significance AK(Bs)=0.39 ± 0.15 ± 0.08 2.3 significance Comparing AK(Bd, Bs) Consistent with SM prediction ≈1.0 H.J.Lipkin, Phys. Lett. B 621, 126 (2005) D. Brown, CKM phase and CP Violation in B Decays

  38. Conclusions • Standard Model CKM CPV is well established • Confirmed by many analyses, several experiments • Unitarity angle precision continues to improve • Sin2 is still statistics limited! • New, innovative techniques are still being developed • CPV provides a unique window on the SM • The mysteries of flavor, generations, matter-anti-matter asymmetry remain unsolved • The existing B-factories will soon be turned off • BaBar,Belle complete in ~2008,Tevatron in ~2009 • Look for final analyses in 2009-2010! • Future flavor physics depends on future facilities • LHCB, super-B, super-Belle, … D. Brown, CKM phase and CP Violation in B Decays

  39. BACKUP

  40. The B-factories Belle KEK-B PEP-II D. Brown, CKM phase and CP Violation in B Decays

  41. Datasets Pep-II BaBar Total ≈ 450 fb-1 Total = ≈ 700 fb-1 KEK-B BELLE D. Brown, CKM phase and CP Violation in B Decays

  42. B0→ D*+- D-+ : b → ccd • Final state not a CP eigenstate • Could show time-integrated charge asymmetry • TDCPA modified by strong phase difference (S+- ≠ S-+, C+- ≠ C-+) • If penguin contribution is zero, C-+ = -C+- , beff=b • If S-+= -S+- ,No CPV sin(2beff) = 0 D. Brown, CKM phase and CP Violation in B Decays

  43. B0→D*+D- B0→D*-D+ NBB = 383M 219 ± 18 signal events 280 ± 19 signal events Hep-ex/0705.1190 S and C in B0→ D*+- D-+ : b → ccd Time-integrated asymmetry consistent with 0 sin(2b) cosd  0 @ 4s No significant direct CPV D. Brown, CKM phase and CP Violation in B Decays

  44. B0 → D03-bodyh0 : b → cud NBB = 383M Nsig = 335 ± 32 BaBar Preliminary (update) • D0→KS+- = coherent ensemble of quasi 2-body decays • (Known) variation of strong phase over Dalitz plot allows extraction of strong and weak phase differences! • Must measure TDCPA at all points in the Dalitz plot • 2-fold ambiguity on  can (in principle) be resolved hep-ex/???? D. Brown, CKM phase and CP Violation in B Decays

  45. B0 → D03-bodyh0 Dalitz Analysis : b → cud BaBar Preliminary B0 tagged h0 = 0,('), B0 tagged K*- K*+ 0 Asymmetry cos2>0 at 84% CL D. Brown, CKM phase and CP Violation in B Decays

  46. B0 → KSK+K- :bsqq • Measure TDCPA at each point on the Dalitz plot • Includes interference between K+K-,KSK± resonances hep-ex/0706.3885 ACP = −0.015 ± 0.077 ± 0.053 eff = 0.352 ± 0.076 ± 0.026 rad 4.8 significance D. Brown, CKM phase and CP Violation in B Decays

  47. B0 → D0CPh0 :b → cud • b → cud tree dominates • b → ucd suppressed ~1/50 • D0CP D0 → KK, KSw • also D*0→ D0CPp0 • h0p0, w, h NBB = 383M Nsig =335±32 background hep-ex/0703019 SM predicts S=-sin2, C≈0 First TDCPA in these modes! D. Brown, CKM phase and CP Violation in B Decays

  48. B0 → KSKS:bdss EW decay phase cancels mixing phase No CPV expected! NBB = 657M K0 Entries/2.5ps B0 tags B0 tags Vtd Nsignal=33±6 B0 K0 d R. Fleischer and S. Recksiegel, Eur.Phys.J.C38:251-259,2004 C background Raw Asymmetry (0,0) BELLE-CONF-0723 S = - 0.38 0.77 0.08 C= +0.380.38  0.05 BaBar result PRL 97 (2006) 171805 SM expectation:S≈0,C≈0 S A.K.Giri and R.Mohanta, JHEP,11,084(2004) D. Brown, CKM phase and CP Violation in B Decays

  49. Constraining in B → a1p via SU(3) • No phase-space overlap between a1+, a1-, and a10 • Can use SU(3) to relate pK and a1K1A • Necessary BFs are measured,  not yet computed Gronau & Zupan, Phys. Rev. D73, 057502 (2006) B0→ a1- B0→ K1+p BaBar Preliminary MB GeV/c2 MK GeV/c2 BF(B0a1- K+)•BF(a1-+--) = 8.2 ± 1.5 ± 1.2 X10-6 Ach(B0a1- K+)= -0.16 ± 0.12 ± 0.01 BF(B+a1+ K0) •BF(a1+++-) =17.4± 2.5 ± 2.2 X10-6 Ach(B+a1+ K0) =0.12± 0.11 ± 0.02 BF(B0K1+(1270)-) = 12.0 ± 3.1 +9.3-4.5 X10-6 BF(B0K1+(1400)-) = 16.7 ± 2.6 +3.5-5.0 X10-6 D. Brown, CKM phase and CP Violation in B Decays

  50. B0→   : buud • Can use Isospin as in +- • ‘pentagon’ relationship -> more terms to measure • New method: use (known) resonance phase variation over Dalitz to analyze EW phase • Eliminates some ambiguities Interference Region. ρ+ π- Monte Carlo ρ-π+ B0→ρ+ π- B0→ρ0 π0 Monte Carlo ρ0π0 B0→ρ- π+ D. Brown, CKM phase and CP Violation in B Decays