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The Future of Flavor Physics at Hadron Colliders CIPANP 2003 K. Honscheid Ohio State University

The Future of Flavor Physics at Hadron Colliders CIPANP 2003 K. Honscheid Ohio State University. B Physics Today. CKM Picture okay CP Violation observed No conflict with SM. sin(2 b ) = 0.734 +/- 0.054. Surprising B Physics. >10 11 b hadrons (including B s ).

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The Future of Flavor Physics at Hadron Colliders CIPANP 2003 K. Honscheid Ohio State University

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  1. The Future of Flavor Physics at Hadron Colliders CIPANP 2003 K. Honscheid Ohio State University CIPANP2003K. Honscheid Ohio State

  2. B Physics Today • CKM Picture okay • CP Violation observed • No conflict with SM sin(2b) = 0.734 +/- 0.054 CIPANP2003K. Honscheid Ohio State

  3. Surprising B Physics >1011 b hadrons (including Bs) CIPANP2003K. Honscheid Ohio State

  4. B Physics at Hadron Colliders • Energy 2 TeV 14 TeV • b cross section ~100 mb ~500 mb • c cross section ~1000 mb ~3500 mb • b fraction 2x10-3 6x10-3 • Inst. Luminosity 2x1032 >2x1032 • Bunch spacing 132 ns (396 ns) 25 ns • Int./crossing <2> (<6>) <1> • Luminous region 30 cm 5.3 cm Tevatron LHC Large cross sections Triggering is an issue All b-hadrons produced (B, Bs, Bc, b-baryons) CIPANP2003K. Honscheid Ohio State

  5. Detector Requirements • Vertex, decay distance • Momentum • PID • Neutrals (g, p0) CIPANP2003K. Honscheid Ohio State From F. Teubert

  6. CDF and D0 • CDF pioneered B physics at hadron collider. • New for Run II • TOF (Particle ID) • Detached Vertex Trigger • Improved tracking • D0 enters B physics • New for Run II • Tracking • Detached Vertex Trigger (soon) CIPANP2003K. Honscheid Ohio State

  7. Atlas and CMS • Acceptance • |h| < 2.5 • Particle ID • ATLAS v.limited p-K separation, ~0.8s from TRD • Di-lepton trigger • Vertexing • Special pixel B layer R~5cm • “Low” luminosity running • Lumi 1033 cm-2s-1 • Only 30fb-1 (3 years) • Specialist B triggers • BUT:DAQ Bandwidth only 100 evts/s to tape for ALL physics ATLAS CIPANP2003K. Honscheid Ohio State From N. Harnew

  8. 100mb 230mb Forward vs. Central Geometry Multi-purpose experiments require large solid angle coverage. Central Geometry (CDF, D0, Atlas, CMS) Dedicated B experiments can take advantage of Forward geometry (BTeV, LHCb) bg b production angle b production angle CIPANP2003K. Honscheid Ohio State

  9. LHCb Light • No tracking stations in magnet region • Reduced material budget • (fringe) magnetic field in tracking station(s) CIPANP2003K. Honscheid Ohio State

  10. The Importance of Particle ID For example: B-> p+p- Purity = 84% ; Efficiency = 90% B0 h+h- s ~17 MeV CIPANP2003K. Honscheid Ohio State

  11. Pixel Detector • Detached Vertex Trigger • Find the primary vertex • Identify tracks which miss it • Calculates the significance of detachment • For EVERY crossing Vacuum Vessel PbWO4 EM Calorimeter • 60 pixel planes • inside magnet • s = 5-10 mm 10500 crystals 220 mm long, 28x28 mm2 Beam Line b,b/sb s(h->gg) ~ 5 MeV s(p->gg) ~ 3 MeV Proper time resolution: 46 fs CLEO/BaBar/BELLE-like performance in a hadron Collider environment! The BTeV Detector CIPANP2003K. Honscheid Ohio State

  12. Fully simulated bb event using Geant 3 • incl. multiple scattering, hadronic interactions • decays in flight • Kalman fitter CIPANP2003K. Honscheid Ohio State

  13. Decay efficiency(%) Decay efficiency(%) B p+p-63 Bo K+p- 63 Bs DsK 74 Bo J/y Ks 50 B- DoK-70 Bs J/yK* 68 B- Ksp-27 Bo K*g 40 Efficiencies and Tagging • For a requirement of at least 2 tracks detached by more than 6s, we trigger on only 1% of the beam crossings and achieve the following trigger efficiencies for these states (<2> int. per crossing): • e efficiency; D  Dilution or (Nright-Nwrong)/(Nright+Nwrong) • Effective tagging efficiency  eD2 • Extensive study for BTeV uses • Opposite sign K± • Jet Charge • Same side p± (for Bo) or K± for (Bs) • Leptons • Conclusion: eD2 (Bo) = 0.10, eD2 (Bs) = 0.13(difference due to same side tagging) CIPANP2003K. Honscheid Ohio State

  14. The Physics Goals • There is New Physics out there: • Baryon Asymmetry of Universe & by Dark Matter • Hierarchy problem • Plethora of fundamental parameters • … • B Experiments at Hadron Colliders are well positioned to: • Perform precision measurements of CKM Elements withsmall model dependence. • Search for New Physics via CP phases • Search for New Physics via Rare Decays • Help interpret new results found elsewhere (LHC, neutrinos) • Complete a broad program in heavy flavor physics • Weak decay processes, B’s, polarization, Dalitz plots, QCD… • Semileptonic decays including Lb • b & c quark Production • Structure: B(s) spetroscopy, b-baryon states • Bc decays CIPANP2003K. Honscheid Ohio State

  15. Part 1: Is the CKM Picture correct? • Use different sets of measurements to define apex of triangle (adopted from Peskin) • Also have eK (CP in KL system) Bd mixing phase Magnitudes Bs mixing phase Can also measure gvia B-DoK- , CIPANP2003K. Honscheid Ohio State

  16. Measuring aUsing Borp  p+p-po • A Dalitz Plot analysis gives both sin(2a) and cos(2a)(Snyder & Quinn) • Measured branching ratios are: • B(B-rop-) = ~10-5 • B(Bor-p+ + r+p-) = ~3x10-5 • B(Boropo) <0.5x10-5 • Snyder & Quinn showed that 1000-2000 tagged events are sufficient • Not easy to measure • p0 reconstruction • Not easy to analyze • 9 parameter likelihood fit Nearly empty (r polarization) Slow p0’s Dalitz Plot for Borp CIPANP2003K. Honscheid Ohio State

  17. Yields for Borp • Based 9.9x106 background events • Bor+p- 5400 events, S/B = 4.1 • Boropo 780 events, S/B = 0.3 Boropo Signal Background po g g mB (GeV) CIPANP2003K. Honscheid Ohio State mB (GeV)

  18. minimum c2 non-resonant non-rp bkgrd resonant non-rp bkgrd Our Estimate of Accuracy on a • Geant simulation of Borp, (for 1.4x107 s) Example: 1000 Borp signal + backgrounds With input a=77.3o CIPANP2003K. Honscheid Ohio State

  19. 6 5 4 3 2 1 Bs Mixing (Vtd/Vts) • Dms (~xs)= DG·C where C can be calculated inside the S. M. • CDF sensitive to xs ~ 30 • DG/G: Bs->yf seen Expect s(DG/G) ~ 2% after Run II • BTeV reaches sensitivity to xs of 80 in 3.2 years CIPANP2003K. Honscheid Ohio State

  20. ± One of several ways to determine g:BsDsK • Theoretically clean, BR ~ 10-4 • ~ 6.5 MeV/c2 s = 418 mm s = 168 mm Bs vtx resolution (mm) Ds vtx resolution (mm) Dsmass (GeV) CIPANP2003K. Honscheid Ohio State

  21. gfrom Bs D-s K+ , D+s K-(II) • Needed: • Hadronic trigger • K/p separation • Good proper time resolution • From the measurement of 4 time-dependent asymmetries one gets g-2dg • 2 same order tree level amplitudes (3) : large asymmetries, NP contributes unlikely • Sensitivity depends upon • relative amplitudes • strong phase difference • values ofg, Dms , DGs /Gs For Dms=20 ps–1: s(g) ~ 10o For Dms=30 ps–1: s(g) ~ 12o In one year: 8k BsDsKreconstructed events CIPANP2003K. Honscheid Ohio State From M. Musy

  22. Measuring c • In the SM the phases and magnitudes are correlated: • l = |Vus| = 0.2205±0.0018 • c is the phase of Vts -> Bs Mixing • Good: Bs->J/yf plus non-trivial angular analysis • Better: Bs -> CP eigenstate such asBsJ/yh() ,hgg,hrg Silva & Wolfenstein (hep-ph/9610208)Aleksan, Kayser & London CIPANP2003K. Honscheid Ohio State

  23. Measuring c II • BTeV can reconstruct h and h’ • Yield in one year • BsJ/y h: 2,800 events with S/B = 15 • BsJ/y h: 9,800 events with S/B = 30 • Error on sin(2c) = 0.024 • With c ~ 2o a precision measurement will require a few years. CIPANP2003K. Honscheid Ohio State

  24. Physics Reach (CKM) in 107 s CIPANP2003K. Honscheid Ohio State

  25. Bc mesons • CDF: mBc = 6.4 +/- 0.4 GeV tBc ~ 0.5 ps • BTeV/LHCb: Precisionmeasurements of mass, lifetime • Search for CPV in Bc -> J/yD+or Bc -> DsD • LHCb acceptance ~30% p (GeV) LHCb preliminary study s(ppBc) ~300 nb 109 Bc/ year Bc  J/y p (BR ~10-2) e ~ 2% 12k events/year Background from B J/y X and prompt J/y reduced cutting on the distance between primary vertex and Bc vertex CIPANP2003K. Honscheid Ohio State M( J/y(mm) p) GeV/c2

  26. Part II: Search for New Physics For a nice overview see: S. Stone “BTeV Physics” athttp://doe-hep.hep.net/P5StoneMarch2003.pdf CIPANP2003K. Honscheid Ohio State

  27. First Example: Supersymmetry • Supersymmetry: In general 80 constants & 43 phases • MSSM: 2 phases (Nir, hep-ph/9911321) • New Physics in Bo mixing: qD,Bodecay: qA,Do mixing: fKp Difference  NP New Physics CIPANP2003K. Honscheid Ohio State

  28. Rare b Decays • Search for New Physics in Loop diagrams • New fermion like objects in addition to t, c or u • New Gauge-like objects in addition to W, Z or g • Inclusive Rare Decays including • bsg • bdg • bsl+l- • Exclusive Rare Decays such as • Brg, K*g • BK*l+l-Dalitz plot & polarization g, l+l- BoK*g CIPANP2003K. Honscheid Ohio State

  29. Yield, S/B for Rare b Decays CIPANP2003K. Honscheid Ohio State

  30. Ali et. al, hep-ph/9910221 Polarization in BoK*om+m- • BTeV data compared to Burdman et al calculation • Dilepton invariant mass distributions,forward-backward asymmetrydiscriminate among the SM and various supersymmetric theories.(Ali, Lunghi, Greub & Hiller, hep-ph/0112300) • One year for K*l+l-, enough to determine if New Physics is present CIPANP2003K. Honscheid Ohio State

  31. Rare Leptonic Decays Bs0  mm Standard Model BR ~ 4x10-9 Here the General Purpose Detectors have an advantage : high pT di-muon triggering at high (1x1034) luminosity. CMS : 100 fb-1 (107s at 1034 cm-2s-1) ~26 signal events 6.4 events background Search alsoforBd0 mm Standard Model BR ~ 1x10-10 Muon trigger : 2m’s with pT > 4 GeV | h| < 2.4 CIPANP2003K. Honscheid Ohio State

  32. Another Example: Extra Dimensions • Aranda & Lorenzo Diaz-Cruz, “Flavor Symmetries in Extra Dimensions” (hep-ph/0207059) (Buras et al. hep-ph/0212143) • Extra spatial dimension is compactified at scale 1/R = 250 GeV on up • No effect on |Vub/Vcb|, DMd/DMs , sin(2b) Bs -> mm –100 –8% g +72% |Vtd| CIPANP2003K. Honscheid Ohio State

  33. Summary • Heavy quark physics at hadron colliders provides a unique opportunity to • measure fundamental parameters of the Standard Model with no or only small model dependence • discover new physics in CP violating amplitudes or rare decays. • interpret new phenomena found elsewhere (e.g. LHC) • Some scenarios are clear others will be a surpriseThis program requires a general purpose B detector like BTeV and LHCb with • an efficient, unbiased trigger and a high performance DAQ • a superb charged particle tracking system • good particle identification • excellent photon detection CIPANP2003K. Honscheid Ohio State

  34. Additional Transparenciesfrom BTeV and LHCb Studies CIPANP2003K. Honscheid Ohio State

  35. dg (= c)from Bs J/y f • In SM fS = -2dg = -2l2h ~10-2 • Sensitive to New Physics effects in the Bs-Bs system In one year: 109 k events Bs J/y (m+m-) f 19 k events Bs J/y (e+e-) f J/y f is not CP eigenstate: needs fit to angular distributions of decay final states as a function of proper time s=36±1 fs Assuming Dms=20 ps–1: s (2dg) ~ 2o CIPANP2003K. Honscheid Ohio State From M. Musy

  36. Current status of LHCbPhysics Reach in 1 year (2fb–1) All numbers will be updated together with more channels in the re-optimization LHCb TDR (September 2003) CIPANP2003K. Honscheid Ohio State From M. Musy

  37. A simplified trigger comparison CIPANP2003K. Honscheid Ohio State From U. Egede

  38. Unitarity Triangles Bd0  p+ p- Bd0  rp BS0  DS p Bd0  DK*0 BS0  DSK Bd0  D* p, 3p BS0  J/y f Bd0  J/yKS0 dg = c CIPANP2003K. Honscheid Ohio State From N. Harnew

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