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Review of Experimental CP-Conserving Processes in Heavy Flavour Physics

Review of Experimental CP-Conserving Processes in Heavy Flavour Physics. J. Michael Roney University of Victoria ( BABAR Member) Chateau de Blois 17 July 2010. standard model's flavour sector. ~two dozen fundamental SM parameters Couplings of EW and strong interactions

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Review of Experimental CP-Conserving Processes in Heavy Flavour Physics

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  1. Review of Experimental CP-Conserving Processes in Heavy Flavour Physics J. Michael Roney University of Victoria (BABAR Member) Chateau de Blois 17 July 2010

  2. standard model's flavour sector ~two dozen fundamental SM parameters • Couplings of EW and strong interactions • Weak mixing angle, Z boson mass • Masses of quarks and leptons • Matrix characterizing the mixing of weak and mass eigenstates of quarks and, recently in extended SM, leptons • Higgs mass, strong-CP angle Heavy flavour sector primarily touches on the Cabibbo-Kobayashi-Maskawa (CKM) matrix J.M. Roney - non-CP Heavy Flavour

  3. W- qi qj GFVij CKM Matrix In SM weak charged transitions mix quarks of different generations Encoded in unitary CKM matrix Unitarity  4 independent parameters, one of which is the complex phase and sole source of CP violation in SM Wolfenstein parameterisation: quark transition J.M. Roney - non-CP Heavy Flavour

  4. CKM Unitarity Triangle Physics beyond the SM signaled by breakdown of unitarity of CKM matrix Wolfenstein parameterisation defined to hold to all orders in l~0.2 and rephasing invariant Area of Δ~CP violation J.M. Roney - non-CP Heavy Flavour

  5. CKM experimental programme • Make as many precision measurements as possible that overconstrain the four CKM parameters (A, λ, ρ,η) • New Physics would be revealed in discrepancies between measurements • Generally requires non-perturbative QCD input to convert measurements to a SM CKM interpretation J.M. Roney - non-CP Heavy Flavour

  6. Programme: Over constrain CKM with broad set of measurements Quantity Sample Measurement(s) Although we probe the charged weak interaction, we need input from strong interaction calculations, which are difficult and often need data J.M. Roney - non-CP Heavy Flavour

  7. Graphically present results as overconstrainedUnitarity Triangle levels@ 95%Prob CKM Fitter group uses frequentist framework UTFit uses Bayesian framework J.M. Roney - non-CP Heavy Flavour

  8. Major experiments providing flavour data… so far KLOE, BNL-E865, KTeV, ISTRA+ and NA48 BESIII @ BEBC II J.M. Roney - non-CP Heavy Flavour

  9. Related Parallel Session talks Semi-leptonic and Leptonic B Decays at B Factories - ElisabettaBarberio(Melbourne) Recent B Physics Results from the Tevatron - Karen Gibson (Case Western) Evidence for Significant Matter-Antimatter Asymmetry at DZero - Derek Strom (UIC) Recent Charm Physics Results from e+e- B Factories - Rolf Andreassen (Cincinnati) Recent Quarkonium Results from the e+e- B Factories - Simone Stracka (Milan) Recent Tau Decay Results at B Factories - Kiyoshi Hayasaka (Nagoya) Recent Results from CLEO - David Cassel (Cornell) Single Top and V_tb at the Tevatron - ReinhardSchwienhorst (Michigan State) Constraints on Quark and Neutrino 4th Generation SM Mixing Matrix - HeikoLacker (Berlin) Highlights of Flavour Violation in the Presence of a 4th Generation - TillmannHeidsieck (Munich) J.M. Roney - non-CP Heavy Flavour

  10. Sample of recent measurements • CP violating measurements will be discussed in the next presentation • Here I'll address a few recent CP-conserving heavy flavour measurements • |Vub| from Semileptonic B decays • B leptonic decays • |Vus| measurements J.M. Roney - non-CP Heavy Flavour

  11. |Vub| from Semileptonic B Decays measurements based on decays with large branching fractions Two experimental approaches: • Inclusive b→ulν • Weak Quark decay + QCD • Exclusive B→Xulν • QCD handled via Form factors with non-perturbative input from e.g. lattice QCD Address experimental issues, such as charm background, differently and have different QCD correction issues J.M. Roney - non-CP Heavy Flavour

  12. Example: recent BaBar result on untagged J.M. Roney - non-CP Heavy Flavour

  13. (BABAR arXiv:1005.3288) Determine |Vub| from simultaneous fit to calculated (lattice QCD) and measured values of partial decay rate as function of q2 • Latest BABAR measuredq2spectrum yields a value of: • Total error has similar contributions from lattice and experimental uncertainties J.M. Roney - non-CP Heavy Flavour

  14. Latest combined fit to data,lattice Inclusive, PDG2010 average: • Difference is a problem and perhaps should be identified as an unattributed uncertainty • work of multiple experiments, multiple theoretical groups. • exclusive result relies on non-perturbative normalization input • inclusive result uses mb, non-perturbative extrapolations and perturbative corrections Predictions from CKM fits: J.M. Roney - non-CP Heavy Flavour

  15. Leptonic Decays Remarkably simple pseudo-scalar (spin = 0, Parity is negative) decays carry information about CKM elements, but come with a 'decay constant' factor which accounts for the strong interaction component • B→τν rate of decay α (fB|Vub|)2 • Ds→τν or Ds→μν rate α (fDs|Vcs|)2 • K→μν rate α (fK|Vus|)2 J.M. Roney - non-CP Heavy Flavour

  16. l+ b + W+ B+ u nℓ l+ b H+ B+ u nℓ Leptonic decays Particularly interesting because some New Physics theories have charged Higgs which contributed to the observed decay rate, e.g. • Additional tree level contribution from a charged Higgs • It does not suffer from helicity suppression, but gets the same ml dependence from Yukawa coupling • Branching fraction theoretical expression depends on the NP model W. S. Hou, Phys. Rev. D 48 (1993) 2342. A.G. Akeroyd and S.Recksiegel J.Phys.G29:2311-2317,2003 J.M. Roney - non-CP Heavy Flavour

  17. B+→τ+ντ Experimental method e+,μ+ X- Fully reconstructthis side: ‘tag’ Then look for signal this side: ‘signal’ νμ,νe ϒ(4S) τ+ B- B+ Two approaches to reconstruct the ‘tag’, which are classified as hadronic or semileptonic • select signal candidate and check that remaining particles consistent with B decay (inclusive Btagreco) • Reconstruct Btag in exclusive modes and check if remaining particles consistent with Bsignal ντ ντ D(*)0 In reality at the ϒ(4S) the B+ and B- decay products all overlap J.M. Roney - non-CP Heavy Flavour

  18. Reconstruct event to select B-events from background… J.M. Roney - non-CP Heavy Flavour

  19. ....and look for excess of missing energy associated with the neutrino J.M. Roney - non-CP Heavy Flavour

  20. B+→τ+ντ Results BABAR Hadronic Phys. Rev. D 77, 011107(R) (2008) BABAR Semi-leptonic Phys. Rev. D 81,051101(R) (2010) BELLE Hadronic Phys. Rev. Lett. 97, 261802 (2006) BELLE Semi-leptonic arXiv:1006.4201[hep-ex] J.M. Roney - non-CP Heavy Flavour

  21. B+→τ+ντ Results world average: B(B+→τ+ν)=(1.73±0.35)x10-4 ~2.5σ higher than expected from CKM fit excluding B+→τ+ν J.M. Roney - non-CP Heavy Flavour

  22. B+→τ+ντ Results same conclusion from UTfit analysis Phys.Lett.B 687, 61 (2010) J.M. Roney - non-CP Heavy Flavour

  23. B+→τ+ντ Results this is not easily attributed to problem with fB because a 2.6σdifference persists when considering: BBdis the ‘bag parameter’ and is calculated on the lattice. J.M. Roney - non-CP Heavy Flavour

  24. Summary of leptonic B decay results J.M. Roney - non-CP Heavy Flavour

  25. Most precise CKM test is from the unitarity condition: From the 1st row of the CKM matrix • |Vub| is negligible in comparison to |Vud| ~1 and |Vus| ~0.2 • |Vud|=0.97425(22) is most precisely obtained from super-allowed nuclear beta decay • |Vus| is most precisely obtained from Kaon decays J.M. Roney - non-CP Heavy Flavour

  26. |Vus| from kaons J.M. Roney - non-CP Heavy Flavour

  27. |Vus| from kaons KLOE, BNL-E865, KTeV, ISTRA+ and NA48 Fit with no CKM unitarity constraint: Fit with CKM unitarity constraint: this analysis fromAntonelli et al arXiv:1005.2323(hep-ph 2010) (usesfK/fπ= 1.193(6) ) J.M. Roney - non-CP Heavy Flavour

  28. |Vus| from inclusive tau decays to kaons:τ+→Xsντ J.M. Roney - non-CP Heavy Flavour

  29. |Vus| from inclusive tau decays to kaons:τ+→Xsντ Belle and BABAR measured many modes with significantly higher precision than previous world averages from LEP and CLEO. Measurements are consistent with previous measurements, but slightly lower. J.M. Roney - non-CP Heavy Flavour

  30. |Vus| from inclusive tau decays to kaons:τ+→Xsντ J.M. Roney - non-CP Heavy Flavour

  31. |Vus| fromBABAR(arXiv:0912.0242) Branching Ratios lattice and experimental: similar contribution to error Value within 1σ of exclusive |Vus| and within 2σ of unitarity J.M. Roney - non-CP Heavy Flavour

  32. |Vus| from BABAR(arXiv:0912.0242) Improve lattice error by taking ratio: Consistent with unitarity J.M. Roney - non-CP Heavy Flavour

  33. Summary and Prospects • Flavour sector provides a means of probing physics beyond the SM at the precision frontier • The SM describes the flavour data, but there are seen a few ‘tensions’ in the flavour sector requiring attention • Looking forward to new data from LHCb and in the future SuperB and SuperKEKB J.M. Roney - non-CP Heavy Flavour

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