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Prelude for practice talk:  I have outdated numbers for the D Hadronic BR analysis  I have the papers and a week so will fix soon.  Tables grabbed from.

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Presentation on theme: "Prelude for practice talk:  I have outdated numbers for the D Hadronic BR analysis  I have the papers and a week so will fix soon.  Tables grabbed from."— Presentation transcript:

1 Prelude for practice talk:  I have outdated numbers for the D Hadronic BR analysis  I have the papers and a week so will fix soon.  Tables grabbed from recent talks but they will be replaced.  Figures will be as they are presented today.  Need to add “preliminary” in some places (WA).  Some “fluff” at beginning will be removed as I think of more important things to say.  Talk is 40 minutes.

2 D Hadronic Branching Fractions And Vub Dan Cronin-Hennessy University of Minnesota CLEO Collaboration May 27, 2005

3  CLEO-c Program  First Results on D Hadronic Branching Fractions  Weak Annihilation Limits from CLEOII/IIV Outline

4 CESR CESR @ Cornell Cornell Electron-positron Storage Ring  e + e - collisions: sqrt(s): 1.8 – 5.6 GeV  Low energy running: Natural damping of beam lost (1/20).  CESR-c: First demonstration of wiggler dominant ring.

5 CLEO

6 RICH Kaon eff = 0.8 Kaon eff = 0.85 Kaon eff = 0.9 CLEO-c B physics Ring Imaging Cherenkov Detector  Designed for B decays.  Clean separation in charm region. K-  separation shown.

7 CLEO-c  (3770) – 3 fb -1 (  (3770)  DD ~  =6 nb) Hadronic D decays Semileptonic D decay (D decay constant, form factors, Vcs,Vcd, Mixing, CPV, rare/nonSM) Accumulated Luminosity: ~ 280/pb Results Today: 60/pb (pilot sample)

8 Hadronic D Branching Fractions Motivation:  Provide most precise measurement of D hadronic BRs.  Many current measurements determined with respect to normalizing modes (e.g. D  K , D  K  ).  CLEO-c will provide absolute measurements.  Counting D mesons provides DD production cross sections.  First step toward improved constraints on D mixing parameters.

9 Hadronic D Branching Fractions Basic Strategy: (for most CLEO-c analyses) D Tagging  Full reconstruction of one D meson (Tag D).  Search remainder of event for signal D decay.  Continuum,  pair, radiative return events suppressed significantly.  Efficiency is analysis dependent -15% to 20%. (Large BR of D mesons and low multiplicity) Single tags are clean

10 Double Tags S = 2*(  *BR)*N DD D = (  *BR) 2 *N DD N DD = S 2 /4D  DD = N DD /L (do not need , BR) Doubly Tagged D +  K -  +  +, D -  K +  -  - Prelim. DATA ~60 pb -1 Simple description

11 Analysis 9 Decay modes measured Simultaneous fit for all BR and cross sections. All correlations taken into account. Single tags: Double tags: To first order B i independent of tag modes and efficiencies. Syst unc cancels.

12 Fits D0 D+ Line shapes include ISR, FSR, resolution, beam energy spread. Efficiencies include FSR correction.

13 Systematics Data Tracking systematic determined using recoil mass: Reconstruct  from  ’     . Peak at  mass 2. MC Pion foundPion not found

14 Results D 0 Modes D + Modes

15 Results *Results from CLEO-c pilot data sample. *Luminosity ~60/pb *Statistical and Systematic unc comparable for some modes. *Expect systematics to scale with luminosity since many of these are determined from data. Agreement with PDG. PDG numbers are correlated among modes. CLEO-c numbers correlated (from simultaneous fit). CLEO-c include FSR correction.

16 Cross Sections Branching fraction analysis fringe benfit: Precision measurement of DD production cross sections. Interesting to note: PDG:  ee and    (  (3770)  hadrons) ~ 10 nb But only a 2 sigma effect at this time. CLEO-c will provide a significantly improved cross section measurement that will allow measurement of non-DDbar y(3770) decays at or below a nb.

17 Charge to Neutral Ratio sqrt(s) MeV Rc/n Predicted Measured Prediction: M. Voloshin (hep-ph/0402170) These (and other) data-theory discrepancies have prompted speculation of 4-quark component of  (3770). See hep-ph/0504197

18 Transition Slide Unitarity Constraints Today With 1000/pb from B factories and CLEO-c lattice calibration CLEO-c will allow B factory measurements to reach full potential by calibrating lattice QCD.  form factor measurements (see Feng Liu’s talk)  D meson decay constant (f D ) (Zhongchao Li’s talk) CLEO II/IIV analyses at Y(4S) energies continue to improve our knowledge of CKM constraints …

19 PRL 88 231803 2002 Lepton energy spectrum B  X u l V ub Inclusive:  Isolating b  u component requires measurement in restricted kinematic regions.  Must know fraction of b  u events in acceptance region.  Progress has been made in last five years by using b to s g to understand b quark fermi motion and b quark mass. This essentially trades modeling uncertainties for experimental uncertainties and has resulted in precision Vub extraction.  Does not remove all sources of theoretical uncertainties.  Must find other ways to limit these uncertainties using additional measurements.

20 Weak Annihilation *Annihilation of valence quarks (leptonic). *Hadronization of residual “brown muck”. *Estimates of rate suggest small contribution from these processes. (Order ~ 1/m H 3 ) *However, if rate is distributed differently than the more dominant b  u production processes then the impact on Vub can be significant. *Extreme example: Leptonic decay, B  l  places rate at the kinematic endpoint.

21 Weak Annihilation Are there methods of quantifying WA experimentally? *High statistics of B-factories will allow comparison of charge and neutral measurements. *D meson analyses at CLEO-c provide additional opportunities (m 3 dependence suggests effects may be larger in charm sector (D 0 /D + width difference) *Or… we can just look directly for WA kinematic signature in available B samples: We have looked. Using CLEOII/IIV data (~10/fb). Approach: Traditional inclusive B semileptonic analysis. Lepton identification plus neutrino recontruction. Observable of interest is lepton-neutrino mass (q 2 spectrum). Look for anomalous rate in high q 2 region. Bump hunting yes but with a model as a guide.

22 WA Search Expected Contributions: *B  X c l Kinematically limited well below B  X u l but still contributes due to experimental resolution. *Continuum *B  X u l (b  u l ) *Weak annihilation?

23 WA Search b  u model: “Hybrid” model which includes resonant and non-resonant modes. Known branching ratios and form factors for resonances. Combined resonant and non- resonant modes follow HQET expectations (with constraints on HQET parameters imposed by b  s  measurements). DeFazio-Neubert: JHEP 99, 017

24 WA Search Weak annihilation model: *Invented for this analysis. *Leptons carry most momentum. *Soft hadronic component, X E x, M x, p x ~  QCD q 2 ~ M B 2 -  M B Distribution function for M x and p x. Flat distribution of width x. Exponential drop dictated by  q 2 for various PDF parameters

25 WA Search q 2 for various PDF parameters 30 models used.

26 WA fits Strategy: Binned  2 fit. 30 bins in q 2. 3 bins in p l.. Fakes and continuum normalization known/fixed. Normalizations for b  c, b  u, and WA float. Results in N b  c, N b  u & N WA.

27 WA fits Sample fit projections.

28 WA fits Sample fit projections. All but b  u and WA subtracted

29 Results Key points: 1)This is a lousy method for measuring the WA rate. The WA model has too much freedom in the kinematics. 2)This a good method for quantifying the impact of WA on V ub. * This analysis is sensitive to WA when these processes contribute significantly in the endpoint region. When such is the case the impact on Vub is large. *If WA processes are spread over a large region of phase space we are not sensitive (and neither is the extraction of V ub ). We quote our results in terms of the “impact” on a “typical” endpoint analysis rather than in terms of WA rates. Ra = “Impact Ratio”

30 Results Endpoint E l >2.2 GeV M x M x <1.55 GeV P l >1.0 GeV/c q 2 and M x q 2 >8.0 GeV 2 M x <1.7 GeV P l >1.0 GeV/c Shape function regime

31 Summary D Hadronic Branching Fractions: I have presented first results from CLEO-c on D hadronic BR fractions. With the pilot data sample (60/pb) we have agreement with PDG and comparable superior uncertainties. Expect significant improvement with new data samples already accumulated (and future data). We have measured 9 D decay modes with double tagging method which provides absolute BRs. We have provided new/improved measurements for critical normalizing modes. We are at the level where careful treatment of radiative corrections is required. DD cross sections and the charge to neutral ratios measured. Future extensions of this analysis will provide new D mixing constraints.

32 Summary V ub : I have presented a preliminary measurement from CLEOII/IIV (10/fb) that allow us to set experimental limits on WA contamination of analyses that extract V ub. The measurement is statistics limited and we are adding data from CLEOIII. We find that the impact on V ub is well below current uncertainties. This approach could be improved with better WA modeling (need help from theory). We have invented our own model which use  QCD as the relevant energy scale for the hadronic component.


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