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Charm and Beauty Physics at Fermilab

Charm and Beauty Physics at Fermilab. Introduction D 0  D 0 Mixing and DCSD Some Dalitz plots. A few lifetimes. X c +  pK - p + P-wave charm. B Physics at the Tevatron. Robert K. Kutschke Fermilab International Conference on Flavor Physics Zhang-Jia-Jie, Hunan, P.R. China

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Charm and Beauty Physics at Fermilab

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  1. Charm and Beauty Physics at Fermilab • Introduction • D0D0 Mixing and DCSD • Some Dalitz plots. • A few lifetimes. • Xc+ pK-p+ • P-wave charm. • B Physics at the Tevatron. Robert K. Kutschke Fermilab International Conference on Flavor Physics Zhang-Jia-Jie, Hunan, P.R. China June 4, 2001 http://home.fnal.gov/~kutschke/talks/Misc/icfp01.pdf

  2. Charm Experiments: Fixed Target • E791 – 1990/91 • 500 GeV/c p- • Target: Pt, C. • Follows: E516,E691,E769 • SELEX (E781) – ran 1996/97 • 600 GeV/c p-, S- • 540 GeV/c p, p+ • Targets: C, Cu. • Goal: charmed baryons • FOCUS (E831) – 1996/97 • 300 GeV/c (max) g • Target: BeO. • Upgraded E687. • Will not include: • Charmonium: Fixed target, Tevatron, anti-p accumulator ring: E835. • Production physics. ICFP2001, June 4, 2001.

  3. At Fermilab g BeO charm g ICFP2001, June 4, 2001.

  4. RICH Beam TRD ICFP2001, June 4, 2001.

  5. Very open trigger. ICFP2001, June 4, 2001.

  6. Properties of Fixed Target Exp’ts. • Segmented Targets • Si -strip detectors • Downstream magnets and tracking systems: • Momentum measurement • Vee’s • Cerenkov based PID • SELEX: RICH • FOCUS,791: Threshold • EM Calorimetry: • FOCUS,SELEX: Pb Glass • E791: Pb liquid scint. • Hadronic calorimetery. • Muon chambers: • FOCUS, E791 only. • High bandwidth trigger/daq. • 791: Very open trigger. • Others more selective. ICFP2001, June 4, 2001.

  7. |primary vtx |secondary vtx BeO BeO Background Subtracted Golden Mode Charm tarsil Decays / 200 mm tarsil Vertexing is the Key Golden Modes: D+ K-p+ p+D0 K-p+D0 K-p+ p+ p- ICFP2001, June 4, 2001.

  8. c u K+, π+ W q = d, s, b d, s, b = q W c u K–, π– SM Expectations for D0 Mixing • Short distance effects from box diagram. Highly suppressed: • GIM mechanism • Long distance effects from common intermediate states. ICFP2001, June 4, 2001.

  9. If CP is Conserved Diagonalize this: These have definite mass and lifetime: M1, M2, G1, G2. Define: Exp’t: x < 0.03 Exp’t: -0.06 < y < 0.01 ICFP2001, June 4, 2001.

  10. Cartoon of Dm and DG Rate Mass ICFP2001, June 4, 2001.

  11. Time Evolution • D0 CP+ (eg K+K-) • D0  CP - • D0  non-CP eigenstate ( eg. K-p+, K-m+nm) Method 1: Compare lifetimes measured in K+K- and K-p+. This measures y. ICFP2001, June 4, 2001.

  12. D0K-m+nmMixing • Tag initial flavor using D*+ D0p+ . • Look for “wrong sign” decays: • SM expectation ( expansion for small x and y): • # of oscillations/mean lifetime = x/2p. Method 2: Measure time dependence of wrong sign Kmn. ICFP2001, June 4, 2001.

  13. D0K+p-: DCSD and Mixing • DCSD: Doubly Cabbibo Suppressed Decay • Wrong sign hadronic modes: both mixing and DCSD. • SM prediction: • t in units of mean lifetime; d=relative phase between dcsd and mixing amplitudes. Method 3: Measure time dependence of wrong sign K+ p-: ICFP2001, June 4, 2001.

  14. Charm Mixing: Theory Predictions From compilation of H.N.Nelson hep-ex/9908021 Triangles are SM xSquares are SM y Circles are NSM x Predictions encompass 15 orders magnitude for Rmix (but only 7 orders of x or y!) ICFP2001, June 4, 2001.

  15. FOCUS yCP Measurement Phys. Lett. B485:62 • Assumes CP invariance. • yCP=y if nature conserves CP • D0 K-K+: CP+ • D0 K- p+: 0.5 (CP++CP-) • Signal and sideband regions shown. • Strong clean up and PID cuts. • Slice into time bins, subtract BG and efficiency correct. • Deal with reflections. N=119738 N=10331 ICFP2001, June 4, 2001.

  16. Acceptance Corrections: • = ( t – ns ), where n is the detachment cut. • f( ) is very flat and is essentially same for K-K+ and K-p+. • Derived from MC: fiducial volume, absorbtion. • s( )  30 fs: no need to convolute resolution. ICFP2001, June 4, 2001.

  17. FOCUS yCP Measurement • Binned Max. Likelihood Fit • Non-parametric treatment of the backgrounds. yCP =(3.42 ± 1.39 ± 0.74)% • Points: background subtracted, f(t’) corrected yields • Lines: Fit results. • t(D0) = 409.2 ± 1.3 (stat only); cuts optimized for y, not t. ICFP2001, June 4, 2001.

  18. E791 yCP Measurement PRL. 83 (1999) p.32 2(GKK - GKp) = 0.04 ± 0.14 ± 0.05 ps-1 yCP =(0.8 ± 2.9 ± 1.0)% ICFP2001, June 4, 2001.

  19. Comparison of y Results World Average ICFP2001, June 4, 2001.

  20. FOCUS: Wrong Sign D0K+p- Phys. Rev. Lett. 86:2955 D*-D mass difference M(Kp) M(Kp) • Tight particle ID + extra hard cuts if M(Kp)  M(pK). ICFP2001, June 4, 2001.

  21. FOCUS RWS Measurement • Points: Fitted D0 yield from previous page. Yield = 149  31 Yield = 36770  195 FOCUS: Rws= (0.404  0.085  0.025)% CLEO: Rws= (0.332+0.063–0.065  0.040)% ICFP2001, June 4, 2001.

  22. Interpretation of RWS Measurement • Time integrated RWS depends on detachment cuts! • Depends on t, not . • Not a good observable: may vary between experiments! • <> is average over true distribution of times. • We believe x is small from semi-leptonic decays. • Determine t / and (t /)2 using MC • Measure RWS : 3 unknowns rDCS , . ICFP2001, June 4, 2001.

  23. Interpretation of RWS Measurement • Using measured RWS , for small x, solve for the allowed region in the rDCS - plane. rDCS (%) ICFP2001, June 4, 2001.

  24. Comparison of Mixing Results • No compelling signal. • If d is small, FOCUS yCP can be compared directly to CLEO . • Both consistent with zero but they have opposite sign! • If opposite sign, implies large d. • Other measurements: • E791: yCP = (0.8 ± 2.9 ± 1.0)% • BELLE(prelim): • E791 Kln: PRL 77:2384,1996. • CLEO: PRL 84:5038, 2000. Preliminary! Preliminary! ICFP2001, June 4, 2001.

  25. E791: D+p-p+p+Dalitz Plot • Resonances included: PRL 86, 770 (2001). S13(GeV4/c2) Fit 1 Fit 2 2-3 Symmetrized 2 1 Non-Resonant 0 0 1 2 S12(GeV4/c2)  = Light Scalar ICFP2001, June 4, 2001.

  26. S13(GeV4/c2) PRL 86, 770 (2001). 2 1 0 0 1 2 S12(GeV4/c2) E791: Unbinned Max Likelihood Fit Two entries/event Symmetrized N/0.05 (GeV2/c4) Fit 1: Without  2/=254/162 80 40 0 Fit 2: With  2/ = 138/162 120 80 40 0 0 1 2 3 M2(-+) (GeV4/c2) ICFP2001, June 4, 2001.

  27. Need a light isoscalar to fit the data:  Fit Fraction Phase (degrees) M() = 4782417 () = 3244221 both in MeV/c2 Can other groups see it? Is it in other channels? ICFP2001, June 4, 2001.

  28. E791: Ds+ p-p+p+Dalitz plot f0(980) f0(1370) Phys. Rev. Lett. 86 (2001) p. 765. • Other resonances present: r0(770), r0(1450) , f2(1270). • Mass and width measurements for the f(980) and f(1370). ICFP2001, June 4, 2001.

  29. SELEX: Lc and D0 Lifetimes Lc+ p K-p+ D0 K-p+ D0  K- p+ p+ p- } +CC No Lc- Reduced Proper time:tR = [L-LMin] M/pc LMin = 8sL Signal regions Sideband regions Binned lifetime analysis OK since s(tR)<< t. ICFP2001, June 4, 2001.

  30. SELEX: Lc and D0 Lifetimes • Reduced Proper time: tR = [L-LMIN] M/pc • Simultaneous Max Likelihood fit to the binned signal and sideband tR distributions. • BG sub, e corrected data. • Background • Acceptance function. t(Lc) = 198.1  7.0  5.6 fs t(D0) = 407.9  6.0  4.3 fs ICFP2001, June 4, 2001.

  31. Observation of Xc+ pK-p+ SELEX FOCUS Lc+ 0.234±0.047±0.022 0.20±0.04±0.02 ICFP2001, June 4, 2001.

  32. Additional Results: Xc+ pK-p+ FOCUS: SELEX: ICFP2001, June 4, 2001.

  33. Observation of the Ds2* at Focus D0K+ D+KS0 First observation of the D+KS0 mode! FOCUS Preliminary There are some real KS0 in the sideband sample. Ds2* has L=1 between quarks. ICFP2001, June 4, 2001.

  34. Simultaneous Fits to D0K+ and D+KS0 Spectra Preliminary Terms in the fit: • DS2 Signal: D-wave Rel. BW • Smooth background shape • MC DS1 feeddown shape • MC DS2 feeddown shape. Significance is not stable with cut variations! • Simultaneous: M and G same. • Errors are statistical only PDG: M = 2573.5 ± 1.7 MeV/c2 G = 15 ± 5 MeV/c2 First observation of D+KS0 mode ICFP2001, June 4, 2001.

  35. Observation of the DS1 at FOCUS Terms in the fit: Preliminary • DS1 Signal: Non Rel BW, convoluted with a gaussian. • Smooth background shape. • DS2* Signal: D-wave Rel BW. • Errors are statistical only PDG: D = 525.35 ± 0.34 MeV/c2 G < 2.3 MeV/c2 @ 90 % CL. ICFP2001, June 4, 2001.

  36. Charm Summary • E791 still going strong 10 years after data taking. • Weak decays, production, strong interaction physics in Dalitz plots, rare decay physics. • FOCUS and SELEX are now starting to publish. • Expect lots more to come: lifetimes, Dalitz plots, charm spectroscopy, mixing and DCSD, rare decays, production … • One recent highlight is the new level of precision available for measurements of mixing and DCSD. • If it’s real, it’s interesting. ICFP2001, June 4, 2001.

  37. B Physics at CDF in Run I • sin2b = 0.79+0.41-0.44 . • First fully reconstructed Bs. • Measurements of mixing in Bd sector. • Limits on mixing in the Bs sector: • Amplitude analysis of B0 J/ K*0 and Bs J/ . • Lifetimes: B+, B0, Bs, Lb. • First observation of Bc. • Production cross-section and differential cross-sections. ICFP2001, June 4, 2001.

  38. B Physics at CDF in Run I … • Limits on rare decays. • Onia production. • b quark fragmentation functions. • J/y and cc, both prompt and from B’s. B Physics at D0 in Run I • Limits on rare decays. • Production cross-section and differential cross-sections. • J/y, both prompt and from B’s. ICFP2001, June 4, 2001.

  39. B Physics at the Tevatron: Run II… • Commissioning runs started in March 2001. • Goal: start real data taking Sept. 2001. • Will run until significant lumi at LHC ( 15 fb-1 ?). • Huge luminosity upgrade • Run I: 100. pb-1 best year • Run II: 2000. pb-1/year ( design lumi ) • Upgraded detectors CDF and D0: • Main physics goals: Higgs, SUSY, Precision top, etc • These require excellent b tagging. • B physics is an important part of these programs • New dedicated B detector 2006: BTeV • Workshop: http://www-theory.fnal.gov/people/ligeti/Brun2/ ICFP2001, June 4, 2001.

  40. CDF Run II Upgrades Electronics, Trigger and DAQ upgraded TOF: t= 25 ps K/ Sep. at 2 to 1.6 GeV/c Layer 00 on beam pipe b: 50m35m ICFP2001, June 4, 2001.

  41. Scintillating Fiber Tracker ICFP2001, June 4, 2001.

  42. Stage I approval received June 2000. 2ndry vertex trigger at Level 1 ICFP2001, June 4, 2001.

  43. Some Comparisons • Compare to e+e- B-factories: • + About 4 orders of magnitude more rate. • + Access to Bs, Bc, and b baryons. • - Poorer S/B; at e+e- initial state well understood. • BTeV vs CDF and D0: • + BTeV is a dedicated b experiment. • + Much better K/p/p particle ID. • ± More aggressive trigger. • - CDF and D0 are running now. ICFP2001, June 4, 2001.

  44. Sensitivity to Bs Mixing • CDF has sensitivity out to 60 for 2 fb-1. • D0 has sensitivity out to 30, for 2 fb-1. This will be one of the first important b physics measurements of Run II. s(xs)  0.2 for all interesting values of xs . ICFP2001, June 4, 2001.

  45. Other Projections for 2 fb-1 • CDF: Errors on B-, B0, Bs and Lblifetimes will decrease 5x. • Bs lifetime difference • CDF: BsJ/yf and Ds(*)+Ds(*)- • s(sin2b) = 0.05 (CDF,D0) • s(sin2b) = 0.025 (BTeV) • BaBar now =±0.2 stat • Projects to ±0.04 stat for 500 fb-1 at PEP II. • Bs DsK • CDF: s(sin(g+d))= 0.4-0.7 ( 0.1 by end of Run II ) • BTeV: s(g) = 7o • BTeV: BsJ/yh(/) , J/yp, Dsp ICFP2001, June 4, 2001.

  46. Other Projections for 2 fb-1 • B0p+p-p0 (rp) • BTeV: O(1000) diluted flavor tagged events. • Compares to a few tens for B-factory at their design lumi. • BTeV: Learning how to do Dalitz plot fits with resolution effects, efficiency and backgrounds. • BsJ/yh(/) : • s(sin2bs ) = 0.03(BTeV) • CDF looking at this too. • BTeV: a lot of charm will pass the b trigger. High precision measurments, or limits, on x, y, rDCs, rare decays. • CDF and D0 have not evaluated how much charm they get. ICFP2001, June 4, 2001.

  47. B Physics at the Tevatron Summary • During Run I B physics was an afterthought but it still produced a wealth of B physics, competitive in many places with CLEO, LEP, SLD. • Run II detectors have B physics designed in. • Great things are expected. Will be competitive with the B-factories in many areas and will exceed them in others. • BTeV will come online near the end of Run II and will carry the B physics program to the end of the decade. It will also have a signficant charm program. ICFP2001, June 4, 2001.

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