Measurements of Hadronic, Semileptonic and Leptonic Decays of D Mesons at E cm =3.77 GeV in CLEO

Measurements of Hadronic, Semileptonic and Leptonic Decays of D Mesons at Ecm=3.77 GeV in CLEOSteven BluskSyracuse UniversityOutline Introduction Hadronic Branching Fractions Semileptonic Decays D+m +nm ConclusionCLEO-c

CESR-c/CLEO-cInner Drift ChamberCLEO-cThe CLEO program has migrated from running on the resonances to the region around the y(3770) Charm factory to study D, Ds mesons -- Broad program of charm physics (3 fb-1 goal) Additional running at J/y (search for exotics in radiative decay) in year 3Accelerator changes - installation of SC wigglers to improve damping higher Ly(3770)yEbeamCLEO-c detector largely same as CLEO-III,Silicon replaced with drift inner chamberB field reduced from 1.5T1.0T Tracking (93% of 4p):16 axial, 31 stereo layers sp/p ~ 0.6 %

CsI (93% of 4p): 6144 crystals (barrel only): sE/E ~ 5% at 100 MeV ~2.2% at 1 GeV Particle ID RICH (80% of 4p) + dE/dxeK>90% for p fake

Some highlights of the CLEO-c Charm Program Precision measurements of D branching fractions

Precise measurements of fD and fDs, the D decay constants. When combined with LQCD will enable ~5% determinations of Vtd and Vts

Pave the road for a more accurate extraction of Vub Measurements of Dpln and Drln form factors will provide tested lattice QCD predictions on heavy-to-light FFs. Extraction of |Vcd|, |Vcs|

Unitarity Triangle Once Vub& Vtd are measured to O(5%) Allows for a stringent test of CKM angles (ie., sin2b) vs sides

CLEO & D TaggingDtagDsigKppTag one D meson in a selected tag mode.Dictates whether final state is D+D- or D0D0Study decays of other D, (signal D)ED Ebeam improves mass resolution by ~10Xe+e- Pure DD final state, no additional particles (ED = Ebeam). Low particle multiplicity ~ 5-6 charged particles/event Good coverage to reconstruct n in semileptonic decays Pure JPC = 1- - initial state Hadronic BF: Use double-tagged and single-tagged yields Semileptonic decays: Dtag + (Dsig Xene), reconstruct ne using Pmiss Leptonic Decays: Dtag + (Dsig mnm)Analysis PreviewAnalyses shown today based on 57 pb-1

Absolute D Hadronic Branching FractionsD+ K-p+p+D+ K-p+ p+p0 D+ Ksp+D+ Ksp+p0D+ Ksp+p+p-D+ K-K+p+D0 K-p+D0 K-p+p0 D0 K-p+p+p-D- K+p-p-D- K+p- p-p0 D- Ksp-D- Ksp-p0D- Ksp-p-p+D- K-K+p-Single Tags: Reconstructed one D meson Double Tags: Reconstruct both D mesons

Fits to DataD0 ModesD+ ModesKpKpp0KpppKppKppp0KspKspp0KspppKKpSignal shape includes: y(3770) line shape, ISR, beam energy spread & momentum resolution* Efficiency includes FSR losses

ModeND (x103)ND (x103)eD (%)Kp5.110.075.150.0765.70.3Kpp09.510.119.470.1133.20.1Kppp7.440.097.430.0944.60.2Kpp7.560.097.560.0951.70.2Kppp02.450.072.390.0727.20.2Ksp1.100.041.130.0445.60.4Kspp02.590.072.500.0723.40.2Ksppp1.630.061.580.0631.40.2KKp0.640.030.610.0342.60.5

Systematic Uncertainties For pion: Look at mass recoiling against J/yp in yJ/yp+p- events Peak at Mp2 for J/yp+p-. Count the number of times the track is found versus not found. Tracking, p0 and Ks all use similar missing mass technique.MCDATAp track foundp track not foundUncertainty 0.7% / (p/K)

SourceValue (%)Tracking / Ks / p00.7 / 3.0 /2.0Particle IDp (0.3) / K (1.3)DE selection1.5G(3770)0.6Final State Radiation0.5 ST / 1.0 DTResonant Substructure0.4 1.5Double DCSD Interf.0.8Fit functions 0.5Data Processing0.3

Preliminary ResultsD0 ModesD+ ModesAs many of the systematics are evaluated using data, they will shrink as LNormalized to PDGto be submitted to PRL

ParameterFitted Value (%)N(D+D-)(1.5580.038012)x105B (D+K-p+p+ )(9.520.250.27) %B (D+K-p+ p+p0 )(6.040.180.22) %B (D+Ksp+)(1.550.050.06) %B (D+Ksp+p0 )(7.170.210.38) %B (D+Ksp+p+p- )(3.200.110.16) %B (D+K+K-p+ )(0.970.040.04) %

ParameterFitted Value (%)N(D0D0)(2.0060.038016)x105B (D0K-p+)(3.910.080.09) %B (D0K-p+p0)(14.94 0.300.47) %B (D0K-p+p+p- )(8.290.170.32) %

Semileptonic Decaysce+eW+|Vcs| , |Vcd| Test LQCD on shape of f+(q2) Use tested Lattice for norm. From B(DXen) extract |Vcd|

Dp FF related to Bp FF by HQS Precise Dp FFs can lead to reduced stheory in |Vub| at B factories Similar for DVln, except 3 FFs enter Can also form ratios, where theory should be more preciseLQCD, PRL 94, 011601 (2005)

Basic TechniqueD0 Tag ModesMBC

Vector Modes: D VeneU = Emiss |Pmiss| (GeV)(~30 events)(~400 events)U = Emiss |Pmiss| (GeV)cs Cabibbo Favoredcd Cabibbo Suppressed(~90 events)(~30 events)First Observation

(~8 events)First Observations(5s)57 pb-1 Data

Preliminary Resultsto be submitted to PRL

Inclusive SemileptonicElectron SpectraCLEO-c PreliminaryD0& D+

Leptonic DecayGoal: Extract fD, and eventually fDs (with precision) Test LQCD, if it passes then trust it in predicting fB, fBs Critical to measuring |Vtd|/|Vts|, one of the sides of the UTG(Btn) ~ 10-4 10-5 difficult

The Technique

ResultsCLEO-c Yellow Book: 1 fb-1Mostly KLp backgroundDATA8 events

BackgroundsModeBF(%)# Eventsp+p00.130.020.310.04K0p+2.770.180.060.05t+n (tp+n)2.64*B(D+m+n)0.30 0.07p0m+n0.250.15negligibleD0/D00.160.16Continuum-0.170.17Total1.000.25

Summary CLEO-c is off to a great start.

With only 57 pb-1 on y(3770) (3 fb-1 proposed), measurements are already comparable or better than world average.

Many more analyses are in the pipeline which I havent had time to discuss. Many more exclusive BRs being investigated Several variants of inclusive and exclusive SL analyses Techniques for estimating systematics established using data. With more data, they will be reduced. Look forward to many precision results in charm physics coming from CLEO.

Backup Slides

Particle ID Use modes where the particle content is unambiguous. For p: D+K-p+p+, D0 Kspp, D0 Kpp0 For K: D+K-p+p+, D0 Kpp0 Then apply tagging requirements If both p & K hypotheses analyzed, 3s dE/dx consistency, and D = ( s(dE/dx)p2 - s(dE/dx)K2 + LogLik(p)- LogLik(K)< 0 (Ng>2) Drop RICH if: RICHDONE is false, or, p(p)0.8Correction applied: (0.30.3)% for p and (1.31.3)% for K

ParticleData eID (%)MC eID (%)eDATA- eMC (%)

p97.570.1397.900.04-0.330.13K89.700.5790.840.10-1.140.58

D Hadronic Systematics DE requirement: compare yields with & without DE cut (1.5%) FSR: Validated using J/ymm, conservatively 0.5% for ST, 1% for DT G3770: Lowe from 30.6 MeV 23 MeV and take shift in data as systematic (0.6%) Resonant substructure: affects efficiencies, depending on mode: 0.4 1.5% Trigger efficiency: trigger simulation 0.1%(Ksp) & 0.2% (K-p+p0) Multiple candidates: Multiple candidates can result in choosing the wrong combination resulting in a loss in efficiency. MC does not model the number of multiple candidates/event well. Affects modes with p0s: 1.30% for Ksp+p0, 0.44% for K-p+ p+p0, 0.32 for K-p+p0 Double DCSD: Unknown relative phase between DCSD & CAD amplitudes (0.8%) Fit functions: 0.5% Data processing 0.3% Quantum (CP) correlations: Negligible

Yield Extraction in D HadronicSignals are fit using: y(3770) line shape, ISR, beam energy spread, momentum resolution (G3770 set to 30.6 MeV, as determined from data; reduced to WA for systematics) Fit double tags first, using DX / DX, then fit single tags with sig pars fixed Disentangle momentum resolution from beam energy spreadBeam Energy, inc. ISRSignal regionSignal Resolution (Signal MC) (5 parameters per D) 3 Gaussian widths (s1,s2,s3) 1.5s1< s2< 4s1 1.5s2< s3< 4s2 Two fractions: f2, f3, (1-f2-f3) Fixes resolution for double & single tag fits in MC & dataBackground 1 correct D +1 incorrect D (fsig * ARGUS) Mispartitioning of daughters ARGUS()*GAUSS(DM) Both Ds are background ARGUS(MD1)*ARGUS(MD2)All candidatesKpp0Kpp0Double Tag Fit to Signal MCCBX 05-06, A. Ryd.

Branching Fraction FittingCBX 04-36 (W. Sun) N = Fitted yields of single & double tags ~ NDD*Bi E = Efficiency matrix diagonal elements are efficiencies off-diagonal are cross-feed probabilities F = background probability matrix n = Raw yields of single & double tags b = estimated backgrounds from other D modesV is the variance matrix, and contains both statistical & systematic uncertaintiesSince eij ei ej, correlated systematics cancel in NDD To first order, Bi is independent of tag modes efficiencies. Corrected yields are given by:Test using Toy MC - 3 neutral + 2 charged modes - no biases - proper error estimation

BackgroundsCross-feedExternal Not simulated in MCBackgrounds that are dependent on fit parameters, ie., NDD, are updated after each iteration..Single TagsDouble Tags: assume only 1 fake contributes, since P(2 fakes) very small

Backgrounds - IIMBC distributions for generic MC after signal modes and backgrounds considered are removed MBC distributions for non-DD MC

Fit to Generic MC(50X Data!)Worst difference is 2.1s, for KppBut this is for 50X data Scale by 50 for data 0.3sstat. Deemed acceptable by committee, and noted in PRL.

Form Factor ShapesNo efficiency corrections, resolution ~ 0.025 GeV2Future goal: slopes ~ 4%, form factors over all q2

In storage rings, damping time is typically proportional to 1/gamma^3, and synchrotron power is proportional to gamma^4.So in reducing the energy from Upsilon Charm region, damping time increases by ~ (1/(1/3)^3) = 27 and synchrotron power decreases by (1/3)^4 = 1/81.

Inner drift chamber is 6 layersNote factor of 2 removed from single tags. N_I is the numberOf D0 tags, NOT number of D0 or D0-bar tags.ISR = Initial State RadiationG(3770) is set to 30.6 MeV as default (average of PDG+CLEO-c data).HQS = Heavy Quark SymmetryFF = form factorRatios in green should be unity, under isospin invariance.Factor of 2 is because of the pi0 wave function. 1/sqrt(2)*(u-ubar+d-dbar)IP Interaction PointData is 14% wider. We use a larger window of +- 0.028 GeV^2

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Measurements of Hadronic, Semileptonic and Leptonic Decays of D Mesons at E cm =3.77 GeV in CLEO