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Centennial APS Meeting Mats Selen, University of Illinois (speaking for the CLEO collaboration)

Charm Physics at CLEO. Centennial APS Meeting Mats Selen, University of Illinois (speaking for the CLEO collaboration) March 23, 1999. This Presentation:. New D 0 mixing results K p mixing analysis (including lifetime) (David Asner) CP-even KK and pp lifetime results (Tony Hill)

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Centennial APS Meeting Mats Selen, University of Illinois (speaking for the CLEO collaboration)

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  1. Charm Physics at CLEO Centennial APS Meeting Mats Selen, University of Illinois(speaking for the CLEO collaboration) March 23, 1999 APS Centennial

  2. This Presentation: • New D0 mixing results • Kp mixing analysis (including lifetime)(David Asner) • CP-even KK and pp lifetime results(Tony Hill) • Charmed Meson Spectroscopy • First observation of broad D1(j=1/2)(Tim Nelson, Harry Nelson) • B(Lc pKp ) absolute measurement • New method described • Preliminary results presented(Dave Besson, Russ Stutz) (Charge conjugation implied throughout) APS Centennial

  3. Our Detector:(CLEO-II & II.V) Svx + HePr APS Centennial

  4. 1996 1997 1998 Our Accelerator(CESR) 9 fb-1 CLEO II.VIntegratedLuminosity CLEO IItook 4.7 fb-1prior to this 32.3 pb-1 DailyLuminosity APS Centennial

  5. Our Data: On(2/3) Off(1/3) This Presentation: Mixing Analysis: 5.7 fb-1 CLEO-II.V (SVX) DJ & Lc Analyses: 4.7 fb-1 CLEO-II APS Centennial

  6. Mixing Analysis: Time evolution of D & D0 mesons Decay eigenstates Define Where APS Centennial

  7. on shell off shell D0 D0 D0 D0 pp,KK… can be relatively large in S.M. small in S.M. Window on New Physics What we are sensitive to in the Kp mixing analysis: Where It will eventually be very important to disentangle “x” and “y” CP eigenstate lifetime analysis will tell us about “y” independent of “x” APS Centennial

  8. p+ D*+ p- D0 D0 K+ p+ D*+ p+ D0 K- Mixing in D0 Kp decays: “wrong-sign” RMIX = “right-sign” But “wrong-sign” events can also come fromDoubly Cabibbo Supressed Decays (DCSD): p+ “wrong-sign” D*+ p- D0 K+ APS Centennial

  9. p+ D*+ p- D0 D0 K+ p+ D*+ p- D0 K+ Mixing vs DCSD: Mixing DCSD • Same initial & final states ! • Bad news if this is all the info available • But theres more... 1) Amplitudes evolve differently in time. 2) Amplitudes can interfere. Can use timing information to help untangle Mixing from DCSD APS Centennial

  10. (Where t is measured in D0 lifetimes) 100% mixed 100% DCSD N(t) RMIX = RDCSD cosf = 1 cosf = 0 cosf =-1 D0 lifetimes t(WS)t(D0) RMIX / (RMIX+RDCSD) The total “wrong-sign” rate is given by: APS Centennial

  11. 5.7 MeV Analysis uses excellent kinematic resolution to stop K-p+ feedthrough, and relies on good Particle-ID to suppress backgrounds. APS Centennial

  12. APS Centennial

  13. Systematic Errors RWS = (0.31  0.09  0.07) % APS Centennial

  14. Aleph: RDCSD 1 RMIX95% CL CLEO-II  1 E791 Klv 90% CL E691 90% CL E791  1 CLEO-II.5  1 Preliminary Results: APS Centennial

  15. Using Lifetime Info: 100% mixed 100% DCSD RMIX = RDCSD N(t) cosf = 1 cosf = 0 cosf =-1 D0 lifetimes t(ws) = ( 0.650.4 (stat+sys) )x t(D0) Exploit this info to limit RMIX APS Centennial

  16. Mixing Results: Aleph: RDCSD 1 RMIX95% CL CLEO-II  1 E791 Klv 90% CL E691 90% CL E791  1 CLEO-II.V 90% CL Preliminary Limits have been calculated for all cosf (ask me after) APS Centennial

  17. on shell off shell D0 D0 D0 D0 pp,KK… can be relatively large in S.M. small in S.M. Window on New Physics What we are sensitive to in the Kp mixing analysis: Where It will eventually be very important to disentangle “x” and “y” CP eigenstate lifetime analysis will tell us about “y” independent of “x” APS Centennial

  18. CP-even Lifetime Analysis: Look for G(D0K-p+)  G(D0p-p+, K- K+) This is a direct measure of DG !(i.e. measure “y” independent of “x”) Plan: Measure t(D0K-p+) t(D0p-p+) t(D0K- K+) Both CP=+1 Should have the same lifetimes D0K-p+ , D0p-p+, andD0K- K+ are easy to distinguish kinematically Don’t need particle-ID APS Centennial

  19. CP-even Yields: APS Centennial

  20. Lifetime Fits: Use unbinned maximum likelihood fit to extract signal lifetimes: APS Centennial

  21. Extracting “y”: Look for G(D0K-p+)  G(D0p-p+, K- K+) Where t+ (t-) are the CP even (odd) lifetimes, and tKp = (t+ + t- )/2 Based on our present measurement: y = -0.032 0.034 or -0.076  y  0.012 (90% CL) CLEO II.V Preliminary APS Centennial

  22. Putting it all together y x CLEO II.V Preliminary APS Centennial

  23. Future mixing prospects CP odd eigenstate lifetime analysis sneak preview Lots more data to analyze APS Centennial

  24. Charm Meson Spectroscopy j=1/2 j=3/2 j=3/2 j=1/2 We search for D1(j=1/2) D1(j=3/2) D2*(j=3/2) Previously not seen B- p- Previously seen D*+p- D0p+ APS Centennial

  25. Analysis Technique • Partial reconstruction: B- DJ0p-; DJ0 D*+p-; D*+ D0p+ • Measure 4-momenta of p-p-p+. • Extract signal via 4-D Max Likelihood Fit • Fitting Technique • 4 independent variables: • helicity q2,helicity q3,azimuth ,M(D*p) • Fit parameters: • Yields (3 resonant, 1 non-resonant) • Mass and width of broad D1(j=1/2) • Mixing and interference between resonances. • Strong phases relative to D1(2420) APS Centennial

  26. 1+ d-wave 1+ s-wave 2+ d-wave cos q3vscos q2 cvscos q2 cvscos q1 Total Background cvscos q2 cvscos q1 cos q3vscos q2 APS Centennial

  27. Total background (see below) D1(2420)0 D2*(2460)0 D01(j=1/2) Fit Results APS Centennial

  28. Weighted Fit Components 1+ s-wave Weighted 1+ d-wave Weighted 2+ d-wave Weighted Background Weighted APS Centennial

  29. With 5.7s significance Preliminary Results • Properties of D1(j=1/2) • (second systematic error due to • uncertainty modeling strong phases) • Spin-Parity assigned to 1+ • Tests of JP favor 1+ over 0- • (closest alternative). • Quark Model: APS Centennial

  30. e+e- Tag charm with one of these cc Baryon tag p D*- Dp-s Lc Xe- ne pK-p+ B(Lc pKp) Absolute • Why? • One of the 4 measured quantities used to normalize all charm analyses B(D0K-p+),B(D+K-p+p+),B(Dsfp+), B(LcpK-p+) • Not well determined at present B(LcpK-p+) = (51.3)% PDG • Our Technique (NEW): Divide event into hemispheres APS Centennial

  31. p p Two versions: Triple correlation analysis (x2): cc D*- or Dp-s pK-p+ Lc Xe- ne cc D*- or Dp-s Lc anything Xe- ne Double correlation analysis: p cc anything pK-p+ Lc p cc D*- Dp-s Lc anything Kp... APS Centennial

  32. Yield examples: (Double correlation analysis) “numerator” LcpK-p+ (same hemisphere as anti-proton tag) “denominator” D0K-p+ (opposite hemisphere from anti-proton tag) Apply efficiency correction and get answer... APS Centennial

  33. p p cc D N D Fake p tag Sounds easy, but... Biggest Backgrounds/Corrections: Falsely increased denominator cc anything Count and correct D cc D D p+ K- Falsely increased denominator Study Kaon fake rate as a function proton momentum and correct (15% effect): After correction, p momentum spectrum looks OK. APS Centennial

  34. Preliminary Results • Make the physics corrections mentioned on previous page (and other smaller ones): • Make appropriate efficiency corrections. B(LcpK-p+ ) Double correlation (4.9  0.5)% Triple correlation (ps tag) (5.2  1.3)% Triple correlation (e tag) (5.6  2.5)% Weighted average: B(LcpK-p+ ) = (5.0  0.5  1.5) % APS Centennial

  35. Future Prospects CLEO-III • Several New Detector Components • RICH, Drift Chamber, Silicon • New CESR cavities & IR • Lots more luminosity APS Centennial

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