Prelude for practice talk:I have outdated numbers for the D Hadronic BR analysisI have the papers and a week so will fix soon.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.

D Hadronic Branching FractionsAnd Vub

Dan Cronin-HennessyUniversity of Minnesota

CLEO CollaborationMay 27, 2005

CLEO-c Program

First Results on D Hadronic Branching Fractions

Weak Annihilation Limits from CLEOII/IIV

Outline

CESRCESR @ Cornell

Cornell Electron-positron Storage Ring

e+ e- collisions: sqrt(s): 1.8 – 5.6 GeVLow energy running: Natural damping of beam lost (1/20).

CESR-c: First demonstration of wiggler dominant ring.

CLEO CsIElectromagnetic

Calorimeter(End Cap)

CsIElectromagnetic

Calorimeter

RICH

Drift ChamberOuter Endplate

Drift Chamber EndplateSmall Radius Section

cos = 0.93

Interaction Point

CESR

ZD Inner Drift Chamber

3560603-002

RICH

Kaon eff = 0.8Kaon eff = 0.85Kaon eff = 0.9

CLEO-c

B physics

Ring Imaging Cherenkov DetectorDesigned for B decays.Clean separation in charm region.

K- separation shown.

CLEO-c

(3770) – 3 fb-1 ((3770) DD ~ =6 nb)Hadronic D decaysSemileptonic D decay (D decay constant, form factors, Vcs,Vcd, Mixing, CPV, rare/nonSM) Accumulated Luminosity: ~ 280/pbResults Today: 60/pb (pilot sample)

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.

Hadronic D Branching Fractions

e

D

e

D

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)

D K

Single tags are clean

Double TagsS = 2*(*BR)*NDD D = (*BR)2*NDD

NDD = S2/4D

DD = NDD/L (do not need , BR)

Doubly Tagged D+K-++, D-K+--

Prelim.DATA ~60 pb-1

Simple description

Analysis

9 Decay modes measured

•Simultaneous fit for all BR and cross sections.

•All correlations taken into account.

iiDDi BNN 2

jiij

ijji

DD NNN

N2

ijj

jij

i NN

B

ijjiDDij BBNN

Single tags:

Double tags:

To first order Bi independent of tag modesand efficiencies.

Syst unc cancels.

FitsD0D+

Line shapes include ISR, FSR, resolution, beam energy spread.Efficiencies include FSR correction.

Systematics

Data

Tracking systematic determined using recoil mass:Reconstruct from ’.Peak at mass2.

MC

Pion found Pion not found

ResultsD0 Modes

D+ Modes

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.

Cross SectionsBranching 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.

Charge to Neutral Ratio

sqrt(s) MeV

Rc/

n

Predicted

Measured

Prediction: M. Voloshin (hep-ph/0402170)

These (and other) data-theorydiscrepancies have prompted speculation of 4-quark component of(3770). See hep-ph/0504197

Transition SlideUnitarity ConstraintsToday

With 1000/pb from B factories and CLEO-c lattice calibration

CLEO-c will allow B factory measurements to reach full potentialby calibrating lattice QCD. form factor measurements (see Feng Liu’s talk) D meson decay constant (fD) (Zhongchao Li’s talk)

CLEO II/IIV analyses at Y(4S) energiescontinue to improve our knowledge

of CKM constraints…

PRL 88 231803

2002

Lepton energy spectrum

BXu l Vub Inclusive: Isolating bu component requiresmeasurement in restricted kinematic regions.Must know fraction of b u events in acceptanceregion.Progress has been made in last five years by using b to s g to understand b quark fermi motionand b quark mass. This essentially trades modelinguncertainties 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.

Weak Annihilation*Annihilation of valence quarks (leptonic).

*Hadronization of residual “brown muck”.

*Estimates of rate suggest small contributionfrom these processes. (Order ~ 1/mH

3)

*However, if rate is distributed differently thanthe more dominant bu production processes then the impact on Vub can be significant.

*Extreme example: Leptonic decay, B l placesrate at the kinematic endpoint.

Weak Annihilation

Are there methods of quantifying WA experimentally?

*High statistics of B-factories will allow comparisonof charge and neutral measurements.

*D meson analyses at CLEO-c provide additional opportunities (m3 dependence suggests effects may be larger in charm sector (D0/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 (q2 spectrum). Look for anomalous rate in high q2 region. Bump hunting yes but with a model as a guide.

WA Search

Expected Contributions:

*B Xc l Kinematically limited well below B Xu l but still contributes due to experimental resolution.

*Continuum

*B Xu l (b u l )

*Weak annihilation?

WA Search

bu 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

WA SearchWeak annihilation model:*Invented for this analysis.*Leptons carry most momentum.*Soft hadronic component, X Ex, Mx, px ~ QCD

q2 ~ MB2 - MB

Distribution function for Mx and px.Flat distribution of width x.Exponential drop dictated by

q2 for various PDF parameters

WA Search

q2 for various PDF parameters

30 models used.

WA fits

Strategy:

Binned 2 fit.30 bins in q2.

3 bins in pl..

Fakes and continuum normalization known/fixed.

Normalizations for bc, bu, and WA float.

Results in N bc, N bu & NWA.

WA fitsSample fit projections.

WA fitsSample fit projections.All but bu and WA subtracted

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 Vub. *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 Vub).

We quote our results in terms of the “impact” on a “typical” endpoint analysis rather than in terms of WA rates. Ra = “Impact Ratio”

Results

EndpointEl>2.2 GeV

Mx

Mx<1.55 GeV

Pl>1.0 GeV/c

q2 and Mx

q2>8.0 GeV2

Mx<1.7 GeV Pl>1.0 GeV/cShape function regime

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.

Summary

Vub:

•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 Vub.

•The measurement is statistics limited and we are adding data from CLEOIII.

•We find that the impact on Vub 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.