1. July, 2006 Selected Topics on Open Charm Physics from CLEO-c 1 Selected Topics on Open Charm Physics at CLEO-c Batbold Sanghi Purdue University ( CLEO Collaboration ) K-K-  - - e+e+ K+K+  (3770)  D 0 D 0 D 0  K +  -, D 0  K - e + Main topics: Overview the CLEO-c experiment and its physics program Absolute Hadronic D 0 and D + Branching Fractions Preliminary Results for Absolute Branching Fractions and Form Factor Measurements in and

2. July, 2006 Selected Topics on Open Charm Physics from CLEO-c2 CLEO-c and the CKM Matrix Recent status Status with theory errors reduced) The CKM matrix provides the only mechanism for CP violation in the SM An important goal of flavor physics is to measure and (over)constrain the parameters in the CKM matrix (4 parameters) to test the SM Non-perturbative hadronic effects limit our ability to extract fundamental parameters from experimental measurements CLEO-c provides unique measurements in the charm sector that test theory and help reduce hadronic uncertainties CLEO-c tested theory can then be applied to B decay processes to extract CKM matrix elements (especially V ub and V td )

3. July, 2006 Selected Topics on Open Charm Physics from CLEO-c3 An example of a test of Lattice QCD Measure form factors in D  l at CLEO-c Theories of Strong Interactions (LQCD) validate LQCD calculations for form factors use LQCD to extract  V ub  from B  l

4. July, 2006 Selected Topics on Open Charm Physics from CLEO-c4 An example of a test of Lattice QCD  m is well measured But |V td | from  m has a large uncertainties from f B measure f D in D  l validate theoretical calculations f B ~f B (LQCD)/ f D (LQCD) f D Use f B to extract |V td | Theories of Strong Interactions (LQCD)

5. July, 2006 Selected Topics on Open Charm Physics from CLEO-c5 CLEO-c impact CLEO-c + Lattice QCD +B factories CLEO-c CLEO-c + Lattice QCD +B factories + ppbar  Vub/Vub 15% l B  l D   Vcd/Vcd 7% l D   Vcs/Vcs =16% l B D  Vcb/Vcb 5% BdBd BdBd  Vtd/Vtd =36% BsBs BsBs  Vts/Vts 39%  Vtb/Vtb 29%  Vus/Vus =1%   l  Vud/Vud 0.1% e p n t b W D hadronic branching fractions (Analysis by Cornell, Purdue and CMU) Including: and D semileptonic B ’s and form factors in ( Analysis by Purdue and SMU, my main thesis topic) I will focus on two CLEO-c analyses that have impact on Vcd, Vcs, Vub and Vcd: D and D s leptonic branching fraction

6. July, 2006 Selected Topics on Open Charm Physics from CLEO-c6 The CLEO-c detector Over 20 years of data taking at Y (4S) An event taken at  (4S) The main components of the CLEO-c detector were developed for B physics at the Y(4S). Minor modifications  Replaced silicon with 6 layer inner drift chamber  B field 1.5 T  1.0 T  P/P = 0.6% at 1GeV  E/E = 2% at 1GeV = 5% at 100MeV Excelent electron and hadron ID Advantages at  (3770)  Pure DD, no additional particle  Low multiplicity  High tagging efficiency Started data taking in the fall of 2003 Note: Log Scale

7. July, 2006 Selected Topics on Open Charm Physics from CLEO-c7 Three generations of CLEO-c analyses at the  (3770): Oct-03 through Jan-04: Luminosity = 56 pb  1 all results are published(D hadronic branching fraction) Sep-04 through Apr-05: Luminosity = 225 pb  1 most analyses are on-going(D semileptonic B ’s and form factors) Future running: projected total Luminosity = 750 pb  1 CLEO-c is also collecting data above the D s D s bar production threshold (goal 750 pb  1 ) and lower energies at the  (2S). CLEO-c data samples

8. July, 2006 Selected Topics on Open Charm Physics from CLEO-c 8 Absolute Hadronic D 0 and D + Branching Fractions Introduction and Overview of the Analysis Measurements of Absolute Hadronic Branching Fractions Summary

9. July, 2006 Selected Topics on Open Charm Physics from CLEO-c9 Overview of Technique e+e+ ee K+K+  ++ K-K- Single tagged D Double tagged D e+e+ ee K+K+  Use 3 D 0 modes and 6 D + modes  K -  +, K -  +,  0, K -  +,  +  -  K -  +  +, K -  +  +  0, K s  +, K s  +  0, K s  +  0, K s  +  +  +, K - K +  +  Reference modes D  K   + and K   +  + normalize many B measurements from other experiments.

10. July, 2006 Selected Topics on Open Charm Physics from CLEO-c10 Overview of Technique Determine separately the and yields  18=2  (3+6) single tags(ST) and 45(=3 2 + 6 2 ) double tag yields(DT) In a combined  2 fitter ( physics/0503050 ), we extract 9 branching ratios and and yields :  Include both statistical and systematic errors (with correlations):  All experimental inputs treated consistently.  Efficiency, cross-feed, background corrections performed directly in fit.  Some systematic errors for and completely cancelled Branching fractions are independent of L and cross-sections. The main variables used in the reconstruction are:

11. July, 2006 Selected Topics on Open Charm Physics from CLEO-c11 Yield Fits Unbinned ML fits to M BC (1D for ST, 2D for DT)  Signal function includes ISR,  (3770) line shape, beam energy smearing, and detector resolution.  Signal parameters from DT fits, then apply to ST.  Background: phase space (“ARGUS function”). D and D yields and efficiencies separated.c M BC (log scale) for ST modes: ISR & beam energy DT signal shape Detector resolution All D 0 DT 2484 ± 51 All D + DT 1650 ± 42 Two dimensional fit allows to separate  ISR and beam energy spread (causes correlated shifts in the mass of the two D’s)  Detector resolution (uncorrelated among these D’s )

12. July, 2006 Selected Topics on Open Charm Physics from CLEO-c12 Systematic uncertainties Dominant error: MC simulation of tracking, K 0 S, and  0 finding efficiencies:  Correlated errors among all particles of a given type add up quickly.  Missing mass technique measure syst errors by comparing data and MC:  Fully reconstruct entire event, but deliberately leave out one particle.  Fraction of MM peak where the last particle is found = efficiency. Example: K  efficiency from D 0  K   +  ≈ 91% in fiducial volume K found (MC) K not found (MC)  K -  +  0, etc. SourceUncertainty (%) Tracking/K 0 s /  0 0.7/3.0/2.0 Particle ID 0.3  /1.3 K Trigger  < 0.2  E cut 1.0—2.5 per D FSR0.5 ST / 1.0 DT  (3770) width 0.6 Resonant substructure 0.4—1.5 Event environment0.0—1.3 Yield fit functions0.5 Data processing0.3 Double DCSD0.8

13. July, 2006 Selected Topics on Open Charm Physics from CLEO-c13 Fit Results (PRL 95,121801) Precision comparable to PDG-04. Statistical errors: ~2.0% neutral, ~2.5% charged from total DT yields.  (systematic) ~  (statistical).  Many systematic errors are measured in data and will be improved with time. Our MC simulation includes FSR  Using efficiencies without FSR would lead to lower B. N DD includes continuum and resonant production. The CLEO-c measurement is the single most precise measurement for every mode

14. July, 2006 Selected Topics on Open Charm Physics from CLEO-c14 Comparisons with other measurements B(D0  K-+)B(D0  K-+) B (D +  K -  +  + ) Other direct meas. Overall C.L 25.9% Reasonable agreement with PDG for all modes  Measurements and errors normalized to PDG. PDG numbers are correlated among modes  PDG global fit includes ratios to K -  + or K -  +  +. No FSR corrections in PDG measurements Our measurements are also correlated (through statistics and efficiency systematics).

15. July, 2006 Selected Topics on Open Charm Physics from CLEO-c15 Results for D cross sections Using a measurement of the luminosity of the data sample (55.8/pb), we obtain CLEO-c inclusive: PRL 96, 092002 Our cross sections are in good agreement with BES [ Phys.Lett. B 241, 278(1990) ] and higher than those of MARKIII [ Phys.Rev.Lett. 60, 89 (1988) ]

16. July, 2006 Selected Topics on Open Charm Physics from CLEO-c 16 Absolute Branching Fractions and Form Factor Measurements in and Introduction and Overview of the Analysis Measurements of Absolute Branching Fractions Measurements of Form Factors Summary

17. July, 2006 Selected Topics on Open Charm Physics from CLEO-c17 Introduction Semileptonic decays are an excellent laboratory to study  Weak physics  QCD physics Gold-plated modes are P  P semileptonic transitions as they are the simplest modes for both theory and experiment:  Cabibbo favored :  Cabibbo suppressed : Main goals of the analysis:  Measure efficiency-corrected absolutely-normalized decay rate distributions and form factors  Measure form factor parameters to test LQCD and model predictions We analyze both D 0 and D + decays. By isospin invariance . This is a nice cross check and adds statistics to improve statistical precision.

18. July, 2006 Selected Topics on Open Charm Physics from CLEO-c18 Overview of the analysis Reconstruct one of the two D’s in a hadronic decay channel. It is called a tagging D or a tag. Two key variables in the tagging D reconstruction are:  Reconstruct from the remaining tracks and showers the observable particles in the final state of a semileptonic decay. Define an observable that can be used to separate signal and background as where E miss and P miss are the missing energy and momentum in the event, approximating the neutrino E and P. The signal peaks at zero in U. Branching fractions are obtained as K-K-  - - e+e+ K+K+  (3770)  D 0 D 0 D 0  K +  -, D 0  K - e + Obtained from Fits to U Obtained from Fits to M bc

19. July, 2006 Selected Topics on Open Charm Physics from CLEO-c19 D 0 and D + tag yields in 281/pb of DATA ~30% event tagging efficiency ~20% event tagging efficiency Examples of M bc for tag modes in the data Tagging provides a beam of D mesons allowing semileptonic decays to be reconstructed with no kinematic ambiguity

20. July, 2006 Selected Topics on Open Charm Physics from CLEO-c20 Measurements of Absolute Semileptonic Branching Fractions

21. July, 2006 Selected Topics on Open Charm Physics from CLEO-c21 Fits to U in 281 pb -1 of Data for Main backgrounds for  Main backgrounds for   Electron fakes from kaons N~7000 N~700

22. July, 2006 Selected Topics on Open Charm Physics from CLEO-c22 Fits to U in 281 pb -1 of Data for Main backgrounds for  Main Backgrounds for  N~2900 N~290

23. July, 2006 Selected Topics on Open Charm Physics from CLEO-c23 Preliminary Results for BFs

24. July, 2006 Selected Topics on Open Charm Physics from CLEO-c24 Reasonable agreement Systematically limitedStatistically limited Comparisons with other experiments and projections for 750 pb -1

25. July, 2006 Selected Topics on Open Charm Physics from CLEO-c25 Measurements of Semileptonic Form Factors

26. July, 2006 Selected Topics on Open Charm Physics from CLEO-c26 Two Fitting Methods: Fit A and Fit B Fit A is a fit to efficiency-corrected and absolutely-normalized d  /dq 2 distributions. This fit is a good match for CLEO-c data as the q 2 resolution is excellent. Fit A is our primary fit as the main goal of our analysis is to obtain d  /dq 2 and f + (q 2 ). Fit B is a fit to the observed decay rate according to a procedure described in D.M.Schmidt, R.J.Morrison and M.S.Witherell in Nucl. Instr. and Meth. A328 547(1993). The technique makes possible a (multidimensional) fit to variables modified by experimental acceptance and resolution. This method has been used by CLEO several times before, for example, to measure form factor ratios in  c  e and B  D * l. Both fitting methods were tested using large Monte Carlo samples. Two fits provide cross-checks. The observed decay rate is related to the true decay rate in the following way: in terms of Acceptance and Smearing functions. The fit has to take into account both effects. We have developed and tested two types of fits.

27. July, 2006 Selected Topics on Open Charm Physics from CLEO-c27 D 0 →K - e + ν D0→π-e+νD0→π-e+ν 700 events S/B ~40/1 CLEOIII(Y(4S):  q 2 ~ 0.4 GeV 2 CLEO-c(  (3770)):  q 2 ~ 0.012GeV 2  q2 ~ 0.012GeV 2  q2 ~ 0.011GeV 2 Raw q 2 distributionq 2 resolution q 2 resolutions and Raw q 2 distributions Note the background in blue 7000 events S/B > 300/1 D0→π-e+νD0→π-e+ν D 0 →K - e + ν

28. July, 2006 Selected Topics on Open Charm Physics from CLEO-c28 Efficiency corrected and absolutely normalized decay rates (DATA) D0→K-e+νD0→K-e+νD+→Kse+νD+→Kse+ν D0→π-e+νD0→π-e+ν D+→π0e+νD+→π0e+ν Subtracting background and applying efficiency corrections (matrices) we find absolute decay rates in bins of q 2 ( The bin width is equal q 2 max /10, the last bins for D 0   e + and D +  0 e + are 2 and 3 times wider ):

29. July, 2006 Selected Topics on Open Charm Physics from CLEO-c29 Efficiency corrected and absolutely normalized decay rates (DATA) These rates can be fit to any form factor model w/o knowing CLEO acceptance and resolution The spectra on the last slide are tabulated here:

30. July, 2006 Selected Topics on Open Charm Physics from CLEO-c30 Form Factor Models Simple pole model : Modified pole model (BK) [Phys.Lett.B 52, 478,417(2000) ] : Series parameterization [.Becher and R.Hill, hep-ph/0509090 ] ISGW2 [ Phys.Rev.D 52,2783,(1985) ] :

31. July, 2006 Selected Topics on Open Charm Physics from CLEO-c31 D 0  K - e + 7000 events D 0   - e + 700 events C-R Prediction Our Fits The efficiency of fits is tested using the Cramer-Rao inequality: The fitter is consistent with being fully efficient. The fitter is consistent with being unbiased. M pole (GeV) Example: The fitting techniques were tested by making ensembles of fits to mock data samples with the number of signal events equal to the expected number of events in the data. We have tested:  Fits for all 4 form factor models  simultaneous fits to isospin conjugate modes  fit with two free parameters [f + (0)V cs and a form factor shape parameter] Tests of Fit A and B

32. July, 2006 Selected Topics on Open Charm Physics from CLEO-c32 Example of a fit (DATA) D0→K-e+νD0→K-e+νD+→Kse+νD+→Kse+ν D0→π-e+νD0→π-e+ν D+→π0e+νD+→π0e+ν Modified Pole (BK) Model:

33. July, 2006 Selected Topics on Open Charm Physics from CLEO-c33 By isospin invariance: The q 2 spectra for isospin conjugate modes are consistent. The plots show: f + (q 2 )V cd D0→πe+νD0→πe+ν D+→π0e+νD+→π0e+ν q 2 (GeV 2 ) D+→KSe+νD+→KSe+ν D0→Ke+νD0→Ke+ν f + (q 2 )V cs q 2 (GeV 2 ) DATA Cross Check 1

34. July, 2006 Selected Topics on Open Charm Physics from CLEO-c34 Cross check 2: Hadron & Electron Spectra & W Helicity D0→K-e+νD0→K-e+ν D+→Kse+νD+→Kse+νD0→π-e+νD0→π-e+νD+→π0e+νD+→π0e+ν Hadron Momentum Electron Momentum cos  W Quantities that are not constrained in the fit are well described

35. July, 2006 Selected Topics on Open Charm Physics from CLEO-c35 Systematic Uncertainties for Form Factor Shape Parameters P K (GeV) Systematic uncertainties that are independent of q 2 (ex: tag M bc fit function) do not change the decay rate shape and hence have a negligible contribution to the shape parameter uncertainty P e (GeV) eff Lepton momentum vs q 2 q 2 (GeV) Kaon ID efficiency P K ~ 100MeV Few events This correlation is not as strong as the hadron momentum correlation Kaon momentum vs q 2 Systematic effects correlated with the hadron (K/K S /  /  0 ) momentum, change the decay rate distribution and lead to modest systematic uncertainties Our studies indicate that the total systematic uncertainty is much smaller than the statistical uncertainty for each semileptonic mode

36. July, 2006 Selected Topics on Open Charm Physics from CLEO-c36 Fit results with two parameters The shape parameters for modified pole, simple pole model and series parameterization with two parameters : The normalization parameter for modified pole model and series parameterization with two parameters :

37. July, 2006 Selected Topics on Open Charm Physics from CLEO-c37 First measurements of form factors for the D + modes; CLEO-c is the most precise for D→πe + D → K e + ν D → π e + ν Comparison with Other Measurements

38. July, 2006 Selected Topics on Open Charm Physics from CLEO-c38 First measurements of form factors for the D + modes; CLEO-c is the most precise for D→πe + D → K e + ν D → π e + ν Comparison with Other Measurements

39. July, 2006 Selected Topics on Open Charm Physics from CLEO-c39 Confidence levels for fits results with 2 parameters The confidence levels for fits with 2 parameters : Which parameterization does the data prefer? The confidence levels for all parameterizations are comparable, as the functional forms for the parameterization are similar and the shape parameters are not fixed. However, the CLEO-c data exclude the ISGW2 (K/  ), pole (K) and modified pole (K) parameterizations when the shape parameters are fixed to the physical values.

40. July, 2006 Selected Topics on Open Charm Physics from CLEO-c40 Data vs. physical basis for shape parameters #1: ISGW2 OutputPhysical value for ISGW2 D 0  K - e + 1.567 ± 0.0451.131 D 0   - e + 1.997 ± 0.1141.410 D +  K 0 e + 1.476 ± 0.0701.131 D +   -0 e + 1.806 ± 0.2091.410 Form factor shape parameters in the data for ISGW2 are inconsistent with the model predictions #2: Pole #3: Modified Pole OutputPhysical value for pole D 0  K - e + 1.94 ± 0.042.112 OutputPhysical Value for effective pole D 0  K - e + 0.26 ± 0.06~1.75 Because the data do not support the physical interpretation of these three parameterizations we use the series parameterization

41. July, 2006 Selected Topics on Open Charm Physics from CLEO-c41 Fit results with 3 parameters Our main form factor shape and intercept results are for the series parameterization : The series is expected to converge rapidly, so only the 1 st few terms are expected to be measurable: we test for three

42. July, 2006 Selected Topics on Open Charm Physics from CLEO-c42 The fit results for 2 and 3 parameters are consistent with each other; Noticeable improvement for  2 for D→Ke + ν with 3 parameters; The  modes do not show this trend as they lack the statistics to probe the third term in the expansion; For D → Ke + ν the 3 rd term b 2 is a order of magnitude larger than b 1. This cannot be interpreted as a lack of convergence if the series because both are consistent with zero indicating that the data does not yet have the sensitivity to determine three parameters simultaneously. Interpretation

43. July, 2006 Selected Topics on Open Charm Physics from CLEO-c43 Comparison Between Parameterizations D0→K-e+νD0→K-e+ν D+→Kse+νD+→Kse+ν D0→π-e+νD0→π-e+νD+→π0e+νD+→π0e+ν --- Simple pole --- Modified Pole --- Series with 2 par  Series with 3 par  Data Data and Fit results are normalized to the fit results for the series parameterization with 3 parameters.

44. July, 2006 Selected Topics on Open Charm Physics from CLEO-c44 Plotted LQCD results (blue) are recent results of FNAL+MILC unquenched three flavor LQCD [ C. Aubin et al., PRL 94 011601 (2005) ]  Lattice systematic uncertainties dominate:  The green lines are our fits to CLEO-c data The dashed lines show 1  (stat+syst) regions DATA FIT LQCD DATA FIT LQCD Form Factors as a Stringent Test of LQCD V cd = 0.2238  0.0029(CKM unitarity, i.e V cd = V us ) V cs = 0.9745  0.0008(CKM unitarity)

45. July, 2006 Selected Topics on Open Charm Physics from CLEO-c45 In these plots, the central values for our projections are equal to the central values from the LQCD results The anticipated precision for a larger 750 pb  1 data sample to be collected in the future D0→K-e+νD0→K-e+ν D0→π-e+νD0→π-e+ν Projections for  and f + (0)

46. July, 2006 Selected Topics on Open Charm Physics from CLEO-c46 V cs(d) and f + (0) determination Using V cs = 0.9745  0.0008 (CKM unitarity) V cd = 0.2238  0.0029 (CKM unitarity, i.e V cd = V us ) Using LQCD results [C. Aubin et al., PRL 94 011601 (2005)]:

47. July, 2006 Selected Topics on Open Charm Physics from CLEO-c47 Summary for D semileptonic studies I have shown preliminary results for D  K/  e + branching fractions and form factor measurements from the 280/pb data sample collected at  (3770). Results of this analysis include:  the most precise branching fraction measurements for these decays  the most precise or first measurements of form factors for these modes  the most precise or first measurements of the efficiency corrected and absolutely normalized decay rates  a stringent test of LQCD calculations of semileptonic form factors

48. July, 2006 Selected Topics on Open Charm Physics from CLEO-c48 Thank you In summary, CLEO-c provides: unique input to test LQCD, the theory capable of solving strongly couple field theory equations, and input to other experiments that help improve their measurements

49. July, 2006 Selected Topics on Open Charm Physics from CLEO-c49 Fit A: a  2 fit to efficiency corrected d  /dq 2 A brief description of the procedure for making Fit A:  Create an N x N efficiency matrix, where N is the number of q 2 bins  Invert the efficiency matrix  Measure raw background subtracted q 2 distributions  Use the inverted efficiency matrix to obtain efficiency-corrected and absolutely- normalized d  /dq 2 (or the form factor) We make fits for form factor parameters to efficiency-corrected and absolutely- normalized d  /dq 2 (or the form factor), using the  2 fitter which includes both statistical and systematic errors (with correlations) :  bin migrations, background uncertainty, and efficiency corrections. The low number of events in the high q 2 bins can lead to biases in  2 fits, we find that the - the decay rate Bias, if any, is SMALL [~0.10  (stat. data) ] - the decay rate estimated from a form factor - the correlation matrix

50. July, 2006 Selected Topics on Open Charm Physics from CLEO-c50 Efficiency Matrices Full efficiency matrix for Efficiency matrices in a truncated form for 10 bins 9 bins 8 bins We use 10 q 2 bins for and. For and we use 9 and 8 bins, respectively. The last bin for these two modes are two or three times wider than other bins. Do not need to read these tables