First Results from CLEO-c

1
First Results from CLEO-c
Thomas Coan
Southern Methodist University
CLEO Collaboration

• CLEO-c Physics Program

• D?? ?? Decays

• Absolute Br(D ? hadrons)

• ee- ? ? (DD)

• Summary

2
CLEO-c Physics Focus
Heavy Flavor Physics overcome QCD roadblock

• CLEO-c precision charm absolute Br measurements

Leptonic decays ? decay constants
Semileptonic decays ?Vcd, Vcs, V_CKM unitarity
check, form factors
Absolute D Brs normalize B physics
Test QCD techniques in c sector, apply to b sector
? improved Vub, Vcb, Vtd, Vts
Physics beyond SM will have nonperturbative
sectors

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

Physics beyond SM where is it?

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

3
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

4
CLEO-c Run Plan
2004 y(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 y(3100) 1 fb-1 1 Billion J/y
decays (170 times MARK III, 15 times
BES II)
5
Tagging Technology
Pure DD/DsDs production ?(3770) ? DD
?s
4140 ? DsDs Large branching fractions (1-15)
High reconstruction efficiency ? High net
tagging efficiency 20
MC
MC
M(D)
6
Absolute Brs w/ Double Tags
Zero bkgnd in hadronic modes
D0 ? K???
w/ D0 ? tag
w/ D? ? tag
D? ? K?????
MC
MC
M(D) (GeV/c2)
w/ 3 fb?1
Mode ?s (GeV) PDG2k CLEOc
(dB/B ) (dB/B ) D0 ?K-p
3770 2.4 0.6 D ? K- pp
3770 7.2 0.7 Ds ?fp 4140
25 1.9
7
fDq from Leptonic Decays
? ( Dq ? l ? ) ? ?f_Dq?2 ?V_cq?2
MC
KL??
Ds ? mn
??
D ? mn
w/ 3 fb-1 3-gen CKM unitarity
CLEO-c ?f/f
PDG ?f/f
Reaction
Decay Constant
f Ds
Ds ? mn
12
1.9
f Ds
Ds ? ?n
33
1.6
f D
D ? mn
50
2.3
8
Semileptonic Decays
MC
MC
1 fb-1
1 fb-1
D0 ? p l n
Measure?f(q2)?2
Kl?
q2 (GeV2)
UE_miss ? P_miss
Mode
PDG04 (?B/B)
CLEOc (?B/B)
? ?Vcd/Vcd ?Vcs/Vcs ? 1.6 ?Vcd/Vcd
5.4 (PDG04) ?Vcs/Vcs 9.3 (PDG04)
3
D0 ? K l n
0.4
D0 ? p l n
16
1.0
D? ? p l n
48
2.0
Ds ? ? l n
25
3.1
9
Probing QCD

• Gluons carry color charge ? binding Glueballs
  ?gg ? and Hybrids ?qqg ?

• Radiative ? decays ideal glue factory

• CLEO-c ?10? J/? decays ? ? 60M J/? ? ?X

Partial Wave Analysis
MC
Absolute Brs ??, KK, pp, ??, ...
?? ?

• E.g. fJ(2220)

?CLEO-c find/debunk fJ(2220)
MC
MC
????
K? K
10
CLEO-c Detector
93 of 4p sE/E 2 _at_1GeV 4 _at_100MeV
B1.0 T
83 of 4p 87 Kaon ID with 0.2 p fake _at_0.9GeV
93 of 4p sp/p 0.3 _at_1GeV dE/dx 5.7 p _at_minI
Data Acquisition Event size 25kB Thruput ?
6MB/s
Trigger Tracks Showers Pipelined Latency
2.5 ms
85 of 4p pgt1 GeV
11
Leptonic Decays D ? ? ??
Br(Dq ? l?)
Seek to measure fD

• fD provides iron post of observation for
  Lattice QCD

• fD useful for checking potential models

• Calibrated Lattice QCD (fB/fD) fD ? fB

• fB B-mixing mments ? Vtd/Vts precision

12
Single D? Tag
ee? ? ?(3770)
?
?
DD?
D-Tag side
Signal side
?

• ?L dt 57 pb?1 _at_ ?s ???????

D? ? K????, K??????, Ks??, Ks??????, Ks????

• D tag side

• ??/K? ID dE/dx RICH

• ?0 recon ? shower shape/location in CsI

• Ks recon ?? kinematic fit to displaced vertex

• Signal side

• 1 track from event vertex, min_I in CsI

• small (lt 250 MeV) neutral ?E in CsI

• no reconstructed Ks

• Key analysis variables

13
MD Distribution v. D Tag
Data
Data
K?????0
K????
Data
Data
Ks??
Ks?????
Data
Ks????
S 28575 ? 286
B 8765 ? 784
14
MM2 Distribution v. D Tag
MC
MC
MC
MC
MC
15
Leptonic Decays Signal Region
? ? 0.024?0.002 GeV2
?Scale MC ?(MM2) w/ data
? (0.024/0.021)?0.025 0.028 GeV2
? ? 0.021?0.001 GeV2
8 evts
D ? K0?
16
Background Results
Background estimates via MC

• D? Background

• ee? ? continuum 0.17 ? 0.17 events

? Oall Bkg 1.07 ? 0.25 events ? 1.07 ? 1.07
events
? 69.9 for D ??? recon.
Br(D ? ???
Preliminary
17
Br(D) ?(DD) Mment _at_ ?s ?(3770)
K
X
Single Tag
Double Tag
??
?
?
e?
e
e?
e
?
?
D0
D0
K?
K?
?
?
S 2NDD B?1
D NDD B2?2
i.e., B ? independent
18
Single and Double Tags

• 10 Single Tag 13 Double Tag modes

D0 ? K??, K???0, K????? c.c.
D ? K???, Ks? c.c.

• Event selection similar to fD analysis

• Key analysis variables

• ?E Ebeam? ?Ei

19
Single and Double Tag Yields

• N(single tags) from ML fit to M_BC

• Line shape parameters from MC

D0 ? K??
D0 ? K??
Data

• N(double tags) from 2-D ML fit to 2-D M_BC

K???0 v. K???0
Data
20
Fit Results for Br(D) and ?(DD)

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

• Fit Output Br(D0 ? K??) , Br(D0 ? K???0),
  Br(D0 ? K?????)

• Fit Input S.T. D.T. yields, ?_tag, ?_bkg
  errors

• ?2/ndof 9.0/16, C.L. 91.4

CLEO-c Preliminary
PDG04
Br(D0 ? K??) 0.039 ? ? ? ?
Br(D0 ? K???0) 0.130 ? ? ? ?
Need pdg comp
Br(D0 ? K?????) 0.081 ? ? ? ?
Br(D ? K???) 0.098 ? ? ? ?
Br(D ? Ks ?) 0.016 ? ? ? ?
N(D0D0) 1.98 x105 ? ?(D0D0) 3.47 ? 0.07 ?
0.15 nb
N(DD?) 1.48 x105 ? ?(DD?) 2.50 ? 0.11 ?
0.11 nb
?(DD) 6.06 ? 0.13 ? 0.22 nb
21
Summary
I need nicer plots for Br(D ? hadrons)
22
Backup
23
1.5 T ? 1.0T
83 of 4p 87 Kaon ID with 0.2 p fake _at_0.9GeV
93 of 4p sp/p 0.35 _at_1GeV dE/dx 5.7 p _at_minI
93 of 4p sE/E 2 _at_1GeV 4 _at_100MeV
CLEO III Detector ? CLEO-c Detector
Trigger Tracks Showers Pipelined Latency
2.5 ms
Data Acquisition Event size 25kB Thruput ?
6MB/s
85 of 4p pgt1 GeV
24
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