1 / 98

Experimental Status of Flavor Physics: Snapshot From CKM2005 (March 05)

Experimental Status of Flavor Physics: Snapshot From CKM2005 (March 05). Vivek Sharma University of California, San Diego. Special Thanks : Andreas Hocker, Kevin Pitts, Ben Grinstein, Zoltan Ligeti, Bob Kowelewski, and Daniele del Re. What This Talk Won’t Cover.

kanoa
Télécharger la présentation

Experimental Status of Flavor Physics: Snapshot From CKM2005 (March 05)

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Experimental Status of Flavor Physics:Snapshot From CKM2005 (March 05) Vivek Sharma University of California, San Diego Special Thanks : Andreas Hocker, Kevin Pitts, Ben Grinstein, Zoltan Ligeti, Bob Kowelewski, and Daniele del Re

  2. What This Talk Won’t Cover • Flavor physics is a vast subject with many subtleties • For a snapshot of this field, see the presentations, discussion and roundtable during CKM2005 workshop(s) at UCSD in March 2005 • http://ckm2005.ucsd.edu/ • In this review I will not cover • Light quark results (Focus of this workshop) • Impressive strides made in (Heavy) flavor theory • “Grade” the “utility” of Lattice results on HF Parameters • http://ckm2005.ucsd.edu/agenda/wed1/bernard.pdf • Important experimental tests of theory of flavors • Discussion of future (super) facilities

  3. Semileptonic B Decays Outline of This Talk Measurements related to Overconstraining the “db’ Unitarity triangle • Facilities for Heavy Flavor Studies : status • Measurements of sides of the Unitarity Triangle • Vcb • Vub • Vtd & Vts : Electroweak penguin and BS Mixing • CP Violation in B Decays and measurements of CKM angles • Direct CPV in B Decays • Gold plated measurement of  with B J/ K0 • Penguin Nuisance in measurement of  = -- • Quest for the angle  in B  DK Direct CPV • Profile of the Unitarity Triangle Circa CKM2005 • Penguin Lust : CP Asymmetries in s-Penguin B Decays and searches for new physics

  4. The Cabibbo Kobayashi Maskawa Matrix VCKM • In the SM, the CKM matrix elements Vij describe the electroweak coupling strength of the W to quarks • CKM mechanism introduces quark flavor mixing • Complex phases in Vij are the origin of SM CP violation • In the Wolfenstein parametrization Mixes the left-handed charge –1/3 quark mass eigenstates d,s,b to give the weak eigenstates d’,s,b’. = 0.226 ± 0.002 A= 0.85 ± 0.05 É= 0.22 ± 0.09 ¿= 0.33 ± 0.05 Experimental goal is precise measurements of magnitudes and phases

  5. Triangles, Triangles, Triangles

  6. Triangles, Triangles, Triangles

  7. Angles of Unitarity Triangle Unitarity Triangles: The “db” triangle For Bu/d System

  8. Facilities for Heavy Flavor Physics BaBar@ PEP-II Belle @ KEK-b CLEO-c @ CESR D0 & CDF @ TeVatron

  9. Era of The Factories: Unprecedented Luminosities ! y’ CLEO-c Ldt>60pb-1 y(3770) Beam Energy (GeV) Ldt >450 fb-1 BELLE Ldt >250 fb-1 CDF & D0 Ldt >800pb-1 Ebeam

  10. Cleo-C Detector Taking Data at e+e-(3770)DD  K- K+ - e+ Complete Survey of Charm Meson Decays • Absolute Charm Branching fractions • Charm decay constants fD • Rates and FF in Semileptonic decays • Strong phases in hadronic D decays critical for CPV measurement in B decays • DD Mixing and CP violation See D. Asner’s talk on Cleo-c results and prospects

  11. CDF& D0 Equipped with Silicon Inner Tracking Intermediate Silicon Layers of CDF CDF D0

  12. Heavy Flavor Physics at CDF& D0 • Silicon gives the “lifetime optic” to CDF & D0, enables lifetime based analyses and trigger…..now proven to work ! • All species of heavy mesons and baryons are produced • Goals • Map out weak decay of all b hadrons, including b and Bc • Exploration of the Bs meson system • Width difference  • Bs Oscillations (take over from LEP/SLD) • CPV studies (Bs mixing and luminosity willing) • Searches for rare decays enhanced by NP • B + - • Electoweak penguin etc

  13. e+  e- Belle and Babar: Dominating B Physics Since ‘99 Excellent Tracking, PID Enough energy to barely produce 2 B mesons, nothing else! B mesons are entangled  Need for Asymm energy collisions

  14. Radiative Penguin Decays: Window to NP b s l+l b sg See Hitoshi Yamamoto’s talk for Details

  15. FCNC Via Electroweak Loops & New Physics ? ? ? Experimentally probed via measurements of decay Rate and Asymmetry

  16. Measurement of Inclusive b s Decay Rate Belle ? Eg > 1.8 GeV Data agrees with SM (10%) BaBar sum of exclusive BaBar Inclusive, Eg > 1.9 GeV CLEO Inclusive, Eg > 2.0 GeV Belle Inclusive, Eg > 1.8 GeV SM Theory uncertainty could improve to ~5% (NNLO) ?? Experimental precision will keep pace (500 fb-1)

  17. BaBar Belle Rate of b d • Decay CKM-suppressed (|Vtd /Vts| ) w.r.t. b s; sensitive to |Vtd| • Inclusive b d measurements background challenged ! • b s   20 background ! Needs K+,KS and KL veto • Exclusive processes are current exptal target:B  () • Theor. estimate imprecise B(B  () )  [0.5-2.0]10-6 : Ali, Buchalla etal • Ratio R(/K*)reduces theory error, estimates |Vtd /Vts| “ At the verge of observation, Central Values in SM range”

  18. Constraint On |Vtd /Vts| Compete with Bs Mixing

  19. Inclusive Rate Of b s l+l

  20. Forward–backward asymmetry(AFB) B backward forward    Lepton pair CM AFB  AFBunder CP: Sensitive to New Physics through Non-SM CPV phases FB Asymmetry in b sl+l As Future Probe of New Physics Ali et al. PRD 66,034002(2002) scenarios consistent with measured rate NP AFB sensitive to relative signs of Wilson coefficients : measurably large BaBar  ACP=0.22  0.26(stat)  0.02(syst) Consistent with SM theory but Data limited Potential to rule out some NP scenarios (where AFB is of opposite sign w.r.t SM) with  500 fb-1

  21.   First Investigations of Bs Oscillations at Tevatron (Following LEP &SLD Searches)

  22. LEP-SLD Limit On Bs Oscillation Using inclusive Bs Samples Amplitude scan Method • Fit Mixing Prob  D*A*cos(Dm t) at fixed Dm • Expect A=1 for real Dm, 0 otherwise • Sensitivity: Dm such that 1.645sA =1 • 95% CL: Dm such that A+1.645sA = 1

  23. Critical Requirements for Bs Oscillation Measurement

  24. Ds+D++ This is the future Bs Samples at Tevatron 5153 signal 900 Bs Ds  with impact parameter trigger

  25. Tevatron Limits On Bs Oscillation World limit (LEP/SLD) unchanged CDF Good first attempt to get in the game (Bs mixing is difficult!!) But must improve not just in dataset but also tagging and propertime resolution • m > 7.9ps-1 @95% CL Sensitivity : m =8.4ps-1

  26.   Measurement of |Vcb| & |Vub| from Inclusive Semileptonic B Meson Decays See Hitoshi Yamamoto’s talk for Details

  27. Inclusive Semileptonic Decays: The Big Picture Inclusive El spectrum Rate Shape |Vxb|2 El[GeV] Inclusive Mx spectrum Shape (log-scale) Rate for Mx<1.55

  28. Partial branching fraction experimental observables Lepton energymoments Hadron massmoments Inclusive Approach Using OPE • Intimate knowledge of QCD is required to go from partonic process to the hadronic states • Given mb >> QCD , OPE used to describe inclusive rates in terms of |Vcb|, mb and a few nonperturbative matrix elements that enter at the order of (QCD/mb)2 and higher orders • One extracts these parameters from a global fit to • Inclusive rate, lepton energy (Eℓ) & hadron mass (mX) moments • Integrations are done for Eℓ > Ecut, with Ecut varied in 0.6–1.5 GeV

  29. Fit Parameters in OPE Expansion BABAR PRL 93:011803 • Calculation by Gambino & Uraltsev (hep-ph/0401063 & 0403166) • Kinetic mass scheme to • Eℓ moments • mX moments • 8 fit parameters • 8 moments available with several Ecut • Sufficient degrees of freedom to determineall parameters without external inputs • Fit quality tells us how well OPE works kinetic chromomagnetic spin-orbit Darwin

  30. Example OPE Fit To BaBar Semileptonic Spectra BABAR PRL 93:011803 ● = used, ○ = unusedin the nominal fit mX moments BABAR c2/ndf = 20/15 Eℓmoments Red line: OPE fitYellow band: theory errors Remarkable agreement between data and theory !

  31. OPE Fits to BaBar Inclusive SL Data PRL 93:011803 • and consistent with B-B* mass splitting and QCD sum rules • and the scale of consistent with theoretical expectations • Remarkable agreement between data and theory Uncalculatedcorrections to G kinetic mass scheme with m = 1 GeV

  32. |Vub| From Inclusive bu l Spectrum • |Vub| can be measured from • The problem: b → cℓv decay Must suppress 50× larger background e.g. using kinematic differences (mu << mc) or particle identification (D*, Kaon content) No perfect observable, All must deal with theory imprecision

  33. Belle 1st and 2nd moment of SF determined Vub From Inclusive Measurements • Experimental requirements in bul signal extraction severely “chops” and reduces the phase space in SL decay • OPE does not provide predictions of differential rates: poor convergence in regions where bcl decays are kinematically forbidden • Non-perturbative shape functions (SF) needed to calculate the extrapolate to full bul spectrum (rate) • Theoretically, only rough features (mean, rms) of the shape functions are known but detailed shape not constrained Use correspondence between Photon spectrum in bs and Lepton energy spectrum in bul Limited by experimental imprecion in Knowledge of the full photon spectrum

  34. BABAR excl(untagged) |Vub| From Inclusive b ul Observables Snapshot of measurements (’04) Example: BaBar Results at CKM2005 Bottomline: Vub measurements approaching 10% precision See Hitoshi Yamamoto’s Talk For Details & BaBar+Belle Averages

  35.   CP Violation in B DecaysMeasurements of Angles of UT Triangle

  36. Loop diagrams from New Physics (e.g. SUSY) can modify SM asymmetry • Clean B mode with “large” rate : • CP Asymmetry measurement is a « Counting Experiment » Observation of Direct CPV in B0K- + T P

  37. BaBar & Belle : Observation of Direct CPV in B Decay Belle BABAR Signal=213953 AK = -0.101  0.025  0.005 Combined BaBar & Belle significance = 5.7 Establishes CPV not just due to phase of B Mixing (M12) Theoretical (npQCD) uncertainties insufficient to prove or rule out NP

  38. B0 B0 fcp fcp B0 B0 B0 B0 fcp fcp 2 2  + + CPV In Interference Between Mixing and Decay CP asymm. can be very large and “cleanly” related to CKM angles Requires time dependent measurement of CP Asymm.

  39. Cartoon of (4S)B0B0 Evolution & Decay

  40. Amplitude ratio Phase of mixing Time-dependent CP Asymmetry Due to Interference in Mixing and Decay (for single weak decay amplitude)

  41. CPV In Interference Between Mixing and Decay: B0 J/K0 CP = -1 (+1) for J/y K0S(L)

  42. B Charmonium Data Samples MES [GeV] MES [GeV] BABAR J/ψ KL signal J/ψ X background Non-J/ψ background (ηCP = +1) ΔE [MeV]

  43. (cc) KSmodes (CP = -1) Sin(2b) Result From B Charmonium K0 Modes J/ψKLmode (CP = +1) background hep-ex/0408127 sin2β = 0.722  0.040 (stat)  0.023 (syst) (PRL 89, 201802 (2002): sin(2β) = 0.741 ± 0.067 ± 0.034)

  44. Sin(2b) Result From B Charmonium K0 Modes Belle sin2β = 0.728  0.056 (stat)  0.023 (syst) WA: sin2β = 0.726  0.037 (5% Measurement)

  45. Measurement of Angle : Dodging Penguins ! [ =-(+) ]

  46. CPV in b u u d Process : B0+- Neglecting Penguin diagram

  47. Tree Penguin Reality in B0+-, + - • Ratio of amplitudes |P/T| and • strong phase difference  • can not be reliably calculated! If no penguins  Spp ~ -0.34 Gronau& London: Estimate dapeng = eff -using isospin relations

  48. Estimating Penguin Pollution in B0+-, + - Similarly for B  system

  49. Rates and Asymmetries in B0 0, B+ - Weak constraint on  [67o -131o] with current statistics

  50. B0+ - System As Probe of  Has Nature’s “Blessing” Blessing # 1 Likelihood projection Although 2 0’s make efficiency small

More Related