Understanding CP Violation and the CKM Matrix: Insights from Niels Tuning

1. CP violationLecture 7 N. Tuning Niels Tuning (1)

3. Recap uI u W W d,s,b dI • Diagonalize Yukawa matrix Yij • Mass terms • Quarks rotate • Off diagonal terms in charged current couplings Niels Tuning (3)

4. CKM-matrix: where are the phases? • Possibility 1: simply 3 ‘rotations’, and put phase on smallest: u W d,s,b • Possibility 2: parameterize according to magnitude, in O(λ): Niels Tuning (4)

5. This was theory, now comes experiment • We already saw how the moduli |Vij| are determined • Now we will work towards the measurement of the imaginary part • Parameter: η • Equivalent: angles α, β, γ . • To measure this, we need the formalism of neutral meson oscillations… Niels Tuning (5)

6. Last hour or so: The basics you know now! • CP violation from complex phase in CKM matrix • Need 2 interfering amplitudes (B-oscillations come in handy!) • Higher order diagrams sensitive to New Physics Examples: • (Direct) CP violation in decay • CP violation in mixing (we already saw this with the kaons: ε≠0, or |q/p|≠1) • Penguins • The unitarity triangle Niels Tuning (6)

7. New physics?? Niels Tuning (7)

8. d Ks ~~ d g,b,…? s B s b t φ s Hints for new physics? 1) sin2β≠sin2β ? 2) ACP (B0K+π-)≠ACP (B+K+π0) ? 4th generation, t’ ? 3) βs≠0.04 ? 4) P(B0s→B0s) ≠ P(B0s←B0s) Niels Tuning (8)

9. Present knowledge of unitarity triangle Niels Tuning (9)

10. “The” Unitarity triangle • We can visualize the CKM-constraints in (r,h) plane

11. Present knowledge of unitarity triangle

12. I) sin 2β

13. I) sin 2β

14. II) εand the unitarity triangle: box diagram CP violation in mixing

15. II) εand the unitarity triangle: box diagram

16. II) εand the unitarity triangle: box diagram Im(z2)=Im( (Rez+iImz)2)=2RezImz

17. II) εand the unitarity triangle ρ Niels Tuning (17)

18. III.) |Vub| / |Vcb| • Measurement of Vub • Compare decay rates of B0 D*-l+n and B0 p-l+n • Ratio proportional to (Vub/Vcb)2 • |Vub/Vcb| = 0.090 ± 0.025 • Vub is of order sin(qc)3 [= 0.01]

19. IV.) Δmd and Δms • Δm depends on Vtd • Vts constraints hadronic uncertainties

20. Present knowledge of unitarity triangle Niels Tuning (20)

21. d Ks ~~ d g,b,…? s B s b t φ s Hints for new physics? 1) sin2β≠sin2β ? 2) ACP (B0K+π-)≠ACP (B+K+π0) ? 4th generation, t’ ? 3) βs≠0.04 ? 4) P(B0s→B0s) ≠ P(B0s←B0s) Niels Tuning (21)

22. More hints for new physics? • 5) εK ? • Treatment of errors… • Input from Lattice QCD BK • Strong dependence on Vcb Niels Tuning (22)

23. More hints for new physics? 6) Vub: 2.9σ?? BR(B+→τυ)=1.68 ± 0.31 10-4 Predicted: 0.764± 0.087 10-4 (If fBd off, then BBd needs to be off too, to make Δmd agree) ? |Vub| avg from semi-lep |Vub| from fit |Vub| from B→τν From: H.Lacker, and A.Buras, Beauty2011, Amsterdam Niels Tuning (23)

24. A.Buras, Beauty2011: Niels Tuning (24)

25. A.Buras, Beauty2011: Niels Tuning (25)

26. m < 0.000003 m < 0.19 m < 18.2 e   me  0.51099890 m  105.658357 m  1777.0 mu  3 mc  1200 mt  174000 md  7 ms  120 mb  4300 quark mixing (4) u’ d’ s’ u d s Vijq = Standard Model: 25 free parameters Elementary particle masses (MeV): Electro-weak interaction: neutrino mixing (4) e(0)  1/137.036 mW  80.42 GeV mZ  91.188 GeV mH >114.3 GeV e   1 2 3 Vijl = mH >114.3 GeV CMS LHCb Strong interaction: s(mZ) 0.117 Niels Tuning (26)

27. W- b gVub u The CKM matrix • Couplings of the charged current: • Wolfensteinparametrization: • Magnitude: • Complex phases: Niels Tuning (27)

28. The CKM matrix • Couplings of the charged current: • Wolfensteinparametrization 1) 2) 3) • Magnitude: • Complex phases: Niels Tuning (28)

29. The CKM matrix • Couplings of the charged current: • Wolfensteinparametrization: • Complex phases: • Magnitude:

30. Remember the following: • CP violation is discovered in the K-system • CP violation is naturally included if there are 3 generations or more • 3x3 unitary matrix has 1 free complex parameter • CP violation manifests itself as a complex phase in the CKM matrix • The CKM matrix gives the strengths and phases of the weak couplings • CP violation is apparent in experiments/processes with 2 interfering amplitudes with different strong and weak phase • Often using “mixing” to get the 2nd decay process • Flavour physics is powerful for finding new physics in loops! • Complementary to Atlas/CMS Niels Tuning (30)

31. Remember the following: • CP violation is discovered in the K-system • CP violation is naturally included if there are 3 generations or more • 3x3 unitary matrix has 1 free complex parameter • CP violation manifests itself as a complex phase in the CKM matrix • The CKM matrix gives the strengths and phases of the weak couplings • CP violation is apparent in experiments/processes with 2 interfering amplitudes with different strong and weak phase • Often using “mixing” to get the 2nd decay process • Flavour physics is powerful for finding new physics in loops! • Complementary to Atlas/CMS Thank you Niels Tuning (31)

32. Backup Niels Tuning (32)

33. PEP-II accelerator schematic and tunnel view SLAC: LINAC + PEPII Linac HER LER

34. PEP-2 (SLAC) Coherent Time Evolution at the (4S) B-Flavor Tagging Exclusive B Meson Reconstruction Vertexing &Time DifferenceDetermination Niels Tuning (34)

35. pT of B-hadron η of B-hadron LHCb: the Detector • High cross section • LHC energy • Bs produced in large quantities • Large acceptance • b’s produced forward • Small multiple scattering • Large boost of b’s • Trigger • ↓ Low pT • Leptons + hadrons (MUON, CALO) • Particle identification (RICH)

36. W q Vq’q q’ Measuring the Quark Couplings • Measure the CKM triangle to unprecedented precision • Measure very small Branching Ratios The well known triangle: β CP phases: γ α γ β Niels Tuning (36)