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First Results from CLEO-c

Thomas Coan

• CLEO-c Physics Program

• D++ Decays

• Absolute Br(D hadrons)

• e+e- (DD)

Southern Methodist University

CLEO Collaboration

• Summary

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CLEO-c Physics Focus

Heavy Flavor Physics: “overcome QCD roadblock”

Leptonic decays decay constants

Semileptonic decays Vcd, Vcs, V_CKM unitarity check, form factors

Absolute D Br’s normalize B physics

Test QCD techniques in c sector, apply to b sector improved Vub, Vcb, Vtd, Vts

Physics beyond SM: where is it?

• CLEO-c: D-mixing, charm CPV, charm/tau rare decays.

• CLEO-c: precision charm absolute Br measurements

• CLEO-c: precise measurements of quarkonia spectroscopy &decay provide essential data to calibrate theory.

Physics beyond SM will have nonperturbative sectors

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Why Charm Threshold?

• Large production , low decay multiplicity

• Pure initial state (DD): “no” fragmentation• Double tag events: “no” background

• Clean neutrino reconstruction

• Quantum coherence:

aids D-D mixing and CPV studies

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CLEO-c Run Plan

2004: (3770) – 3 fb-1

18M DD events, w/ 3.6M tagged D decays (150 times MARK III)

2005: s 4100 MeV – 3 fb-1

1.5M DsDs events, w/ 0.3M tagged Ds decays (480 times MARK III, 130 times BES)

2006: (3100) – 1 fb-1

1 Billion J/ decays (170 times MARK III, 15 times BES II)

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Tagging Technology

Pure DD/DsDs production: (3770) DD s ~4140 DsDs

Large branching fractions (~1-15%) High reconstruction efficiency

High net tagging efficiency ~20%

M(D)

MC

MC

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Absolute Br’s w/ Double Tags

~ Zero bkgnd in hadronic modes

Mode s (GeV) PDG2k CLEOc (B/B %) (B/B %)

D0 K-+ 3770 2.4 0.6D+ K- ++ 3770 7.2 0.7Ds 4140 25 1.9

MCMC

M(D) (GeV/c2)

D0 K D K

w/ 3 fb1

w/ D0 tag w/ D tag

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fDq from Leptonic Decays

( Dq l ) f_Dq2 V_cq2

w/ 3 fb-1 & 3-gen CKM unitarity:

CLEO-cf/f

PDGf/f

ReactionDecay Constant

f Ds Ds+ 12% 1.9%

f D D+ ~50% 2.3%

f Ds Ds+ 33% 1.6%

Ds+

D+

KL

|fD|2

l

|VCKM|2

MC

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Semileptonic Decays |VCKM|2

|f(q2)|2= = V_cq2Br ( D P l ) / D

V_cq2 f(q2)2d ( D P l ) / dq2

MC MC

D0 l

Kl

U=E_miss P_miss

1 fb-1 1 fb-1

q2 (GeV2)

Measuref(q2)2

D0 l D l

D0 K l

Ds l

Mode PDG04 (B/B%) CLEOc (B/B%)

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3 0.4

4825

1.02.03.1

Vcd/Vcd & Vcs/Vcs 1.6%

Vcd/Vcd = 5.4% (PDG04)

Vcs/Vcs = 9.3% (PDG04)

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Probing QCD• Gluons carry color charge binding: Glueballs = gg and Hybrids = qqg

X

cc̄

• Radiative decays: ideal glue factory

• CLEO-c: 10 J/ decays 60M J/ X

Partial Wave Analysis

Absolute Br’s: , KK, pp, , ...

• E.g.: fJ(2220)

MC

MCMC

CLEO-c: find/debunk fJ(2220)

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CLEO-c Detector

B=1.0 T93% of 4E/E = 2% @1GeV = 4% @100MeV

85% of 4p>1 GeV

83% of 4% Kaon ID with 0.2% fake @0.9GeV

Data Acquisition:Event size = 25kBThruput 6MB/s

Trigger : Tracks & Showers PipelinedLatency = 2.5 s

93% of 4p/p = 0.3% @1GeVdE/dx: 5.7% @minI

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Leptonic Decays: D+ +

Br(Dq l) =m

2

l2

m_Dq

(1 - ) f_Dq|Vcq| _Dq

2 22

l8GF

2

m_Dqm

Strong Physics

Weak Physics

• fD+ provides “iron post of observation” for Lattice QCD

• “Calibrated” Lattice QCD (fB/fD) + fD fB

• fD+ useful for checking potential models

Seek to measure fD+

• fB + B-mixing m’ments |Vtd/Vts| precision

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Single D Tag

L dt = 57 pb1 @ s =

D tag side: D K+, K+, Ks, Ks, Ks

• /K ID: dE/dx + RICH

• 0 recon: shower shape/location in CsI

• Ks recon: kinematic fit to displaced vertex

Key analysis variables:

MM2 = (Ebeam E)2 ( pD p )2

MD = Ebeam ( pi)222

Signal side:• 1 track from event vertex, min_I in CsI• “small” (< 250 MeV) neutral E in CsI• no reconstructed Ks

e+e (3770)

D+D D-Tag side

Signal side

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K+

Ks

K+0

Ks+

Ks

Data Data

DataData

Data

MD Distribution v. D Tag

S: 28575 286B: 8765 784

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MM2 Distribution v. D Tag

MC

MC

MCMC

MC

(MM2) 0.025 GeV2

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Leptonic Decays: Signal Region

Data

Ks++ Tag

8 evts

0.0240.002 GeV2

0.0210.001 GeV2

D KsCheck MC (MM2) w/ data:

D+ K0+

Scale MC (MM2) w/ data:

= (0.024/0.021)0.025 = 0.028 GeV2

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Background + Results

Br(D+ + = Ntag

Nsig

Br(D+ + = (3.5 1.4 0.6) x 104

fD+ = (201 41 17) MeV

D Background:Mode # of Events

D+ +D+ K+

D+ +D+ +

0.31 0.040.06 0.050.36 0.08negligible

D0D0 Background: 0.16 0.16 events

Background estimates via MC

e+e continuum: 0.17 0.17 events

O’all Bkg: 1.07 0.25 events 1.07 1.07 events

Preliminary

& = 69.9% for D+ + recon.

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Br(D) & (DD) M’ment @ s = (3770)

K +

ee+

X

D0

D0

K +

ee+

D0

D0

K+

Single Tag Double Tag

S = 2NDD B1 D = NDD B22

w/ 2 1 :2 NDD =

S2

4D

S2

4DL (DD) = i.e., B & independent

B = 2DS

1

2

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Single and Double Tags

D0 K+, K+0, K++ + c.c.

D+ K++, Ks+ + c.c.

Determine 5 Br’s and (e+e D0D0) & (e+e D+D)

10 Single Tag + 13 Double Tag modes

Event selection similar to fD+ analysis

Key analysis variables:

E = Ebeam Ei

MBC = (Ebeam ( pi)2)2

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Single and Double Tag Yields

• N(single tags) from ML fit to M_BC • Line shape parameters from MC

MC

D0 K+

Data

D0 K+

• D and D fit together: same signal param’s, indep. bkg.

Data

• N(double tags) from 2-D ML fit to 2-D M_BC K+0 v. K+0

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Fit Results for Br(D) and (DD)

• Fit Input: S.T. & D.T. yields, _tag, _bkg + errors

• 2/ndof = 9.0/16, C.L. = 91.4%

• 2 fit to account for correlations btwn single/double tags, bkg

• Fit Output: Br(D0 K+) , Br(D0 K+0), Br(D0 K++)

Br(D+ K++), Br(D+ Ks+) and N(D0D0), N(D+D)

Br(D0 K+) = 0.039 ? ?

Br(D0 K+0) = 0.130 ? ?

Br(D0 K++) = 0.081 ? ?

Br(D+ K++) = 0.098 ? ?

PDG04CLEO-c Preliminary

N(D0D0) = 1.98 x105 (D0D0) = 3.47 0.07 0.15 nb

N(D+D) = 1.48 x105 (D+D) = 2.50 0.11 0.11 nb

Br(D+ Ks +) = 0.016 ? ?

(DD) = 6.06 0.13 0.22 nb

Need pdg comp

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Summary

I need nicer plots for Br(D hadrons)

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Backup

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1.5 T 1.0T

93% of 4p/p = 0.35% @1GeVdE/dx: 5.7% @minI93% of 4E/E = 2% @1GeV = 4% @100MeV

83% of 4% Kaon ID with 0.2% fake @0.9GeV

85% of 4p>1 GeV

Trigger : Tracks & Showers PipelinedLatency = 2.5 s

Data Acquisition:Event size = 25kBThruput 6MB/s

CLEO III Detector CLEO-c Detector

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J/ X Inclusive - Spectrum

MC

• Inclusive -spectrum

Search for monochromatic E.g., 24% efficient for fJ(2220) 10 sensitivity for narrow resonances

• Modern 4 detector

Suppress hadronic bkgnd: J/X

• Huge data set

Plus and (1S) data

Determine JPC and gluonic content