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Recent (Charm) Electroweak Results from CLEO

Recent (Charm) Electroweak Results from CLEO. Content I : The CESR-c and the CLEO-c Experiment. II : Leptonic D decays. III : Semileptonic D decays: Exclusive IV : Semileptonic D decays: Inclusive V: Inclusive BF of D  Xl n and l n VI : CPV from CLEO II.V VII : Summary & Future.

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Recent (Charm) Electroweak Results from CLEO

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  1. Recent (Charm) Electroweak Results from CLEO • Content • I: The CESR-c and the CLEO-c Experiment. • II: Leptonic D decays. • III: Semileptonic D decays: Exclusive • IV: Semileptonic D decays: Inclusive • V: Inclusive BF of D Xln and ln • VI: CPV from CLEO II.V • VII: Summary & Future. Moriond EW sessionMarch 5-12, 2005La Thuile, Italy Doris Y. KimUniversity of IllinoisUrbana-Champaign CLEO / Doris Kim

  2. I. The Cornell Electron Storage Ring (CESR) Added 12 superconducting wigglers to CESR for low energy running. Ebeam = 1.5 – 5.6 GeV CLEO / Doris Kim

  3. The CLEO-c Detector Run plan: ´, (3770) and Ds, J/  thresholds. CLEO-c  CLEO III det. • New inner drift chamber replaced old silicon vertex • 1T B field (old 1.5 T) • Track (93% of 4p): s = 0.6% @ 1 GeV • PID: Rich (80% of 4p), dE/dx, EM calorimeter, muon (> 1GeV) • E:s = 2.2% @ 1 GeV, 5% @ 100 MeV. CLEO / Doris Kim

  4. Impact of CLEO-c Measurements  Electroweak Physics: Vcq e+ W+ An example of semileptonic decay • Leptonic decays givefD and fDs • validate Lattice QCD and improve fB • Semileptonic decays give Vcs, Vcd and form factors • test theoretical form factor models • enhance LQCD calculations, which will improve B decay form factors. • test CKM unitarity. • Improved (already) BF measurements of many important normalization modes and more coming. • Hadronic decays measure strong phases, needed for CPV. • Initial state is coherent: Ideal for charm mixing and CPV. QCD: form factors D CLEO / Doris Kim

  5. The Future of Precision Flavor Physics l l l Vub/Vub 5% e B B n n n K n n p p p  Vcb/Vcb 3% Vcd/Vcd 1.7% Vcs/Vcs 1.6% l l l l l D n D n D B B n n n l K p D D K D n p Vts/Vts 5% Vtd/Vtd 5% W t b Bd Bd Bd Bd Bs Bs Bs Bs CLEO-c + Lattice QCD +B factories CLEO-c + Lattice QCD +B factories + ppbar CLEO-c The Goal: Measure all CKM matrix elements and associated phases in order to over-constrain the unitary triangles. Vus/Vus 1% Vud/Vud 0.1% Vub/Vub 15% Vcb/Vcb 5% Vcd/Vcd 7% Vcs/Vcs 16% Vtb/Vtb 29% Vtd/Vtd 36% Vts/Vts 39% CLEO / Doris Kim

  6. (3770) Analysis Techniques  K- K+ Fully reconstruct 1st D “the tag”, then analyze decay of 2nd D to extract exclusive or inclusive properties. - e+ (3770) ~ DDbar threshold • No extra fragmentation = simpler geometry / combination • Clean neutrino reconstruction • High tagging efficiency at 25% of all D’s produced. CLEO / Doris Kim

  7. Examples of CLEO-c Tagged D samples ~60,000 tagged D0 decays From Dec 03 to Mar 04, we collected the first 60pb-1 @ 3770 MeV with 6 wigglers, corresponding to 360,000 DDbar pairs. Basic selection / fit variables are … Signal: Gaussian + bifurcated GaussianBackground: ARGUS function Preliminary MBC plots from semileptonic BF study CLEO / Doris Kim

  8. A “D hadronic tag” is required. An additional charged track as m+ and no extra shower > 250 MeV as a signal. Fit “missing-mass”2 II. Leptonic Decays: D+m+n Tag D n m+ Signal D ~60 pb–1 Yellow Book Phys. Rev. D, 70, 112004 (2004) 8 signal candidates 1fb-1 CLEO / Doris Kim

  9. fD from Absolute Br(D+  m+n) |fD|2 |VCKM|2 Vcd (1.1%) from 3 generation unitarity tD+ (0.3%)well-measured • The first CLEO-c paper published.Phys. Rev. D, 70, 112004 (2004) • Based on 60 pb–1, 28651 tags and 8 signal events. • Background is ~ one event. • BES • Lattice 2004 • CLEO-c • Isospin Mass Splittings • Potential Model • Rel. Quark Model • QCD Sum Rules • QCD Spectral Sum Rules • MILC • UKQCD Mark III <290 MeV BES I: 1 event (1998) BES II: 3 events (2004)fD ~ 371 MeV ICHEP 2004 CLEO / Doris Kim

  10. III. Exclusive Semileptonic BF.  e+ W+ Vcq Analysis Techniques c MC Fit to U q D P, V Fit to MBC • Reconstruct one hadronic D tag. • Reconstruct a semileptonic signal candidate from the remaining tracks/showers. • Fit kinematic variable U( = Emiss – |Pmiss| ) for the missing neutrino of the signal. Decay rate for D  P Latest LQCD, PRL 94, 011601 (2005) CLEO / Doris Kim

  11. Signal Candidates of Neutral Semileptonic Modes. Cabibbo favored modes Cabibbo suppressed modes The first 60pb-1 (~1400 events) (~110 events) First Observation (~90 events) (~30 events) Preliminary U ( = Emiss – |Pmiss| ) plots CLEO / Doris Kim

  12. Signal Candidates of Charged Semileptonic Modes. Cabibbo suppressed modes Cabibbo favored modes (~60 events) (~500 events) Events / ( 10 MeV ) Events / ( 10 MeV ) (~400 events) Events / ( 10 MeV ) Events / ( 10 MeV ) (~30 events) Preliminary U ( = Emiss – |Pmiss| ) plots The first 60pb-1 CLEO / Doris Kim

  13. The Preliminary Exclusive BF. (8 events) World First Observation Events / ( 10 MeV ) The first 60pb-1 Preliminary Preliminary U( = Emiss – |Pmiss| ) CLEO / Doris Kim

  14. Or We Can Do Without D Tagging! Signal MC Background MC With D Tag, we have cleaner signal sample, but we loose statistics. What if we do not use D Tagging? Let’s try for D  K/p e n decays. • Require a signal: one e± and one K or p • Assume the other tracks/showeres are coming from the other D, ID them using dE/dx, RICH and EM calorimeter information.  Calculate Pmiss • Fit on E, MBC CLEO / Doris Kim

  15. Semileptonic Events without D Tagging Data Data K en p en p e n K e n Bkgd Bkgd p0 e n p0 e n KS(p+p-) e n KS(p+p-) e n K0other e n K0other e n D+D- Bkgd D+D- Bkgd tMC tMC Cont MC Cont MC Fakes Fakes Data Data KS(p+p-)en p 0en p0 e n KS(p+p-) e n Bkgd Bkgd p e n p e n K e n K± e n K0other e n K0other e n D+D- Bkgd D+D- Bkgd tMC tMC Cont MC Cont MC Fakes Fakes Preliminary CLEO / Doris Kim

  16. IV. Inclusive Semileptonic BF. Preliminary P(e+) spectra PDG(2004) B(D0 X e+n) = 6.87 ± 0.28 % PDG(2004) B(D+ X e+n) = 17.2 ± 1.9 % Analysis Techniques • Reconstruct one hadronic D tag. • Signal e+ : ID’d by dE/dx, RICH and E/p calorimeter • Right/Wrong sign defined by K charge for D0, signal side charge for D+  background subtraction by wrong sign events. CLEO-c (in D rest frame) Cut-off CLEO / Doris Kim

  17. Expected Uncertainty from the First 60 pb-1 tag mode tag mode Preliminary No BR yet CLEO / Doris Kim

  18. V: Inclusive BF of D Xln, ln Low Q2 s e+ W+* Low Q2 s e+ W+* Electron and Neutrino Spectra are Different! Conservation of angular momentum  nget boost from W+ in the lab frame. Analysis Techniques • Reconstruct one hadronic D tag. • Signal side: ID’d by dE/dx, RICH and E/p calorimeter, than add all. • Get Pmiss and Mmiss^2. • KL suppression is important. CLEO / Doris Kim

  19. MC Example of Emiss Spectra Red = signal Blue = background Black = Red + Blue D0 MC D± MC D±  ln Emiss(GeV) Emiss(GeV) CLEO / Doris Kim

  20. The Inclusive D  Xln, ln Candidates MC Data 60 pb-1 Missing Energy (GeV) KL Background KL Background Signal Signal CLEO / Doris Kim

  21. VI. CPV search in D0  Ksp+p- from CLEO II.V D0 + D0bar D0 - D0bar • PRL 92, 142001 (2004) • D0 / D0bar tagged by D*  D0p+(slow). • Standard Model prediction at 10–6 for this channel from K mixing.  sensitive to new physics • Dalitz technique studies decay amplitude, not decay rate.  sensitivity increase. M(Ksp-) M((p+p-) M(Ksp+) CLEO / Doris Kim

  22. VII: Summary and Future • New results on BF D+mnand fD • (2) Exclusive BF of semileptonic decays coming (pretty) soon. • With just 60 pb-1, stastistical power of many decay modes already at the world best. • The world first events of and • We have two analysis options available: With and wo DTag • (3)Inclusive BF of D Xen and D Xln, ln coming. • (4) Currently we are running at (3770) with 12 “8-pole” wigglers. More data is coming on (3770), Ds threshold, etc. fDs CLEO / Doris Kim

  23. Question slides CLEO / Doris Kim

  24. CLEO-c Impacts on the Unitarity Triangle Now: Theory Uncertainties Dominate Future: With CLEO-c, improved LQCD and 500 fb-1 each from the B factories CLEO / Doris Kim

  25. Electron Spectrum of Inclusive Events time Very Preliminary CLEO-c (in D rest frame) CLEO / Doris Kim

  26. Charged D Meson Tags – Distributions of Mbc ~30,000 tagged D± decays Preliminary MBC plots from semileptonic BF study CLEO / Doris Kim

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