1. 1 Absolute Hadronic D 0 and D + Branching Fractions at CLEO-c Werner Sun, Cornell University for the CLEO-c Collaboration Particles and Nuclei International Conference 24-28 October 2005, Santa Fe, NM Introduction to analysis techniques Results from three analyses Future directions

2. PANIC05, 24-28 October 2005, Santa Fe, NMWerner Sun, Cornell University 2 Overview of Techniques  e  e    (3770)  DD  Kinematics analogous to  (4S)  BB: identify D with   (M BC ) ~ 1.3 MeV, x2 with  0   (  E) ~ 7—10 MeV, x2 with  0  Single tag (ST): n i = N DD B i  i  Double tag (DT) : n ij = N DD B i B j  ij  Take advantage of low multiplicity, low backgrounds.  Example: MC tracking, K 0 S, and  0 efficiency systematics:  Missing mass (MM) technique to compare data and MC.  Fully reconstruct entire event, but deliberately leave out one particle.  Fraction of MM peak where the last particle is found = efficiency. K found (MC) K not found (MC) Example: K  eff from D 0  K   +  ≈ 91% in fiducial volume  note different scales DD X i DD j i

3. PANIC05, 24-28 October 2005, Santa Fe, NMWerner Sun, Cornell University 3 Three Analyses  MARK III double tag technique, using 55.8 pb -1  Independent of L and cross sections.  Correlated systematic uncertainties cancel.  Combine ST and DT yields in  2 fit for B and N DD.  Published in PRL 95, 121801 (2005).  D + → K 0  +, using 281 pb -1  Reconstruct K 0 inclusively, search for K 0 S /K 0 L asymmetry.  Presented at EPS2005, abstract #185.  D → n(  + ) m(  0 ), using 281 pb -1  Cabibbo-suppressed transitions, low statistics.  Isospin analysis of D → . D0D0 K+K+ K+K+ K++K++ D+D+ K++K++ K++0K++0 KS+KS+ K0S+0K0S+0 K0S+-+K0S+-+ K+K+K+K+ PRELIMINARY Reduce error on V cb Probe strong phases

4. PANIC05, 24-28 October 2005, Santa Fe, NMWerner Sun, Cornell University 4 M BC (log scale) for ST modes: D+D Double Tag Analysis  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.  Background: phase space (“ARGUS function”).  D and D yields and efficiencies separated. ISR & beam energy DT signal shape Detector resolution ModeN D (10 3 )  D  (%) KK 5.11±0.075.15±0.0765.1±0.2 K   9.51±0.119.47±0.1131.6±0.1 K  7.44±0.097.43±0.0943.8±0.1 K  7.56±0.09 51.0±0.1 K   2.45±0.072.39±0.0725.7±0.1 K0sK0s 1.10±0.041.13±0.0445.7±0.3 K 0 s   2.59±0.072.50±0.0722.4±0.1 K 0 s  1.63±0.061.58±0.0631.2±0.1 KK  0.64±0.030.61±0.0341.1±0.4 All D 0 DT 2484 ± 51 All D + DT 1650 ± 42

5. PANIC05, 24-28 October 2005, Santa Fe, NMWerner Sun, Cornell University 5 Double Tag Analysis: Fit Results  Fit includes both statistical and systematic errors (with correlations) [arXiv:physics/0503050].  Precision comparable to PDG WA.   (systematic) ~  (statistical).  Many systematics measured in data, will improve with time.  Simulation includes FSR, so we measure B (final state + n  ).  Using efficiencies without FSR correction would lower B.  N DD includes continuum and resonant production.  L = (55.8 ± 0.6) pb -1 → cross sections  Consistent with BES measurements. ParameterValue no  FSR NDDNDD (2.01±0.04±0.02)x10 5 -0.2% B(K+)B(K+) (3.91±0.08±0.09)%-2.0% B(K+)B(K+) (14.9±0.3±0.5)%-0.8% B(K++)B(K++) (8.3±0.2±0.3)%-1.7% ND+D-ND+D- (1.56±0.04±0.01)x10 5 -0.2% B(K++)B(K++) (9.5±0.2±0.3)%-2.2% B(K++0)B(K++0) (6.0±0.2±0.2)%-0.6% B(KS+)B(KS+) (1.55±0.05±0.06)%-1.8% B(K0S+0)B(K0S+0) (7.2±0.2±0.4)%-0.8% B(K0S+-+)B(K0S+-+) (3.2±0.1±0.2)%-1.4% B(K+K+)B(K+K+) (0.97±0.04±0.04)%-0.9% (D0D0)(D0D0) (3.60±0.07 +0.07 -0.05 ) nb -0.2% (D+D-)(D+D-) (2.79±0.07 +0.10 -0.04 ) nb -0.2%  (+-)/  (00) 0.776±0.024 +0.014 -0.008 +0.0%

6. PANIC05, 24-28 October 2005, Santa Fe, NMWerner Sun, Cornell University 6 Comparison with PDG 2004  Measurements and errors normalized to PDG.  PDG global fit includes ratios to K -  + or K -  +  +.  No FSR corrections in PDG measurements.  Our measurements also correlated (statistics and efficiency systematics). B(D0  K-+)B(D0  K-+) B (D +  K -  +  + ) Other direct meas. Overall C.L 25.9%

7. PANIC05, 24-28 October 2005, Santa Fe, NMWerner Sun, Cornell University 7 D + → K 0 S,L  +  Search for asymmetry between K 0 S and K 0 L branching fractions.  Caused by interference: constructive for K 0 L, destructive for K 0 S.  O(10%) predicted by Bigi & Yamamoto [PLB 349 (1995) 363-366].  Depends on relative strong phases between amplitudes.  D + → K 0 S  + already measured in double tag analysis.  Now, reconstruct K 0 s + K 0 L inclusively in missing mass (MM) recoiling against  +. c d w+w+ s d u d D+D+ ++ K0K0 Cabibbo-favored c d s d u d D+D+ ++ K0K0 w+w+ Color-suppressed c d d s u d D+D+ ++ K0K0 w+w+ DCS and color-suppressed S,L tag side signal side inferred from missing mass DATA ++ KK  D  → K 0 S,L   K 0 S,L D+ → K++D+ → K++ ++ fully reconstructed

8. PANIC05, 24-28 October 2005, Santa Fe, NMWerner Sun, Cornell University 8 D + → K 0 S,L  + : Results  B (D + → K 0 S  + ) + B (D + → K 0 L  + ) = (3.06 ± 0.06 ± 0.16)%  Asymmetry = (K 0 L  K 0 S )/(K 0 L + K 0 S ) =  0.01 ± 0.04 ± 0.07  Consistent with O(10%) prediction.  Also, B (D + →  + ) = (0.39 ± 0.03 ± 0.03)% [ PDG2004 has (0.30 ± 0.06)% ].  Dominant background from  +.  Many small backgrounds from other D + decays.  All shapes determined from MC.  Statistical error 1.9%  Systematic error 5.2% PRELIMINARY D + → K 0  + (3879 ± 71 events) D + →  + (487 ± 38 events) D + →  +  D + →  0  + (176 ± 13 events) (Missing mass) 2 (GeV 2 ) DATA

9. PANIC05, 24-28 October 2005, Santa Fe, NMWerner Sun, Cornell University 9 M BC distributions in  E signal region and  E sidebands D → n(  + ) m(  0 )  Study Cabibbo-suppressed D decays with single tags only.  Double tag technique not as profitable—statistics too low.  Normalize B s to reference modes.  MC tuned to match  mass spectra in data.  Background from Cabibbo-favored decays with K 0 S →  +  -,  0  0.  Veto M(  ) near K 0 S mass. D0D0 D+D+ M(+-)M(+-) M(00)M(00) Reference modes

10. PANIC05, 24-28 October 2005, Santa Fe, NMWerner Sun, Cornell University 10 D → n(  + ) m(  0 ): Results  Some first observations (circled).  Use PDG04 + CLEO-c for reference B s.  Also search for substructure: ,   Compare M(  +  -  0 ) in  E signal and sideband regions.  B (   ) consistent with MM analysis.  Isospin analysis of  :  A 2 /A 0 = 0.423 ± 0.014 ± 0.055  cos  = 0.10 ± 0.05 ± 0.11  Evidence for final state interactions. D + →  +  +  -  0 Mode B (x10 -3 ) PDG (x10 -3 )  1.40±0.04±0.031.38±0.05  0.78±0.05±0.040.84±0.22  13.3±0.2±0.511±4  < 0.30---         7.42±0.14±0.277.3±0.5         10.2±0.6±0.7---           4.31±0.44±0.18---  1.23±0.06±0.061.33±0.22  3.36±0.10±0.163.1±0.4  4.80±0.27±0.34---  11.7±0.4±0.7---           1.67±0.18±0.171.82±0.25   3.56±0.24±0.213.0±0.6   0.61±0.14±0.05---     1.66±0.47±0.10--- PRELIMINARY    

11. PANIC05, 24-28 October 2005, Santa Fe, NMWerner Sun, Cornell University 11 Summary and Future Directions  One major goal of CLEO-c: measure hadronic D branching fractions.  Reduce error on V cb.  Test CKM unitarity.  Provide insight on strong interactions (long- and short-distance).  Branching fractions in current data sample competitive with world averages.  B (D 0  K -  + ) measured to 3.1% (PDG 2.4%).  B (D +  K -  +  + ) measured to 3.9% (PDG 6.5%).  First observations of some multibody pionic channels.  Two+ more years of data taking.  Will lower statistical and systematic errors.  D s branching fractions with √s ~ 4 GeV running.