CLEO-c

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CLEO-c CESR-c Probing Physics Behind Beyond
the Standard ModelMats Selen, University of
Illinois2002 Aspen Winter Conference on
Particle Physics
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What is CESR-c CLEO-c

• CLEO-III detector
• CESR running at lower energies

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CLEO-c Detector
Detector Works Great! Presently running on
?(1S) (Ecm 9460 MeV)
RICH 83 of 4p 87 Kaon ID with
0.2 p fake _at_0.9GeV
Solenoid 1.5 T now,... 1.0T later
Tracking 93 of 4p sp/p 0.35 _at_1GeV dE/dx
5.7 p _at_minI
Calorimeter 93 of 4p sE/E 2 _at_1GeV
4 _at_100MeV
85 of 4p For pgt1 GeV
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The Run Plan (More or Less)
2002 Prologue Upsilons 1-2 fb-1 each at
Y(1S),Y(2S),Y(3S), Spectroscopy,
matrix element, Gee, ?B hb 10-20 times
the existing worlds data (started Nov 2001)

2003 y(3770) 3 fb-1 30 million DD
events, 6 million tagged D decays (310
times MARK III)
C L E O c
2004 MeV 3 fb-1
1.5 million DsDs events, 0.3 million tagged Ds
decays (480 times MARK III, 130 times
BES)
2005 y(3100), 1 fb-1 y(3686) 1
Billion J/y decays (170 times MARK III,
20 times BES II)
A 3 year program
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The CESR machine group is good
One day scan of the ?(1/29/02)
L 1 x 1030(BES)
Ecm L (1032 cm-2 s-1)
3.1 GeV 2.0
3.77 GeV 3.0
4.1 GeV 3.6
When weadd Wigglers
?Ebeam 1.2 MeV at J/?
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The Big Idea Tagging

• Very clean events !
• Flavor ID
• Unambiguous Reconstruction

MC
Log scale!


Beam constrained mass

• Even though we will have less data, our final
  errors in many important charm analyses will be
  significantly smaller than those possible at the
  b-factories.

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Why CLEO-c ? Why Now ?

• We expect great advances in flavor and
  electroweak physics during the next decade
• Tevatron (CDF, D0, BTeV,CKM).
• B-Factories (BaBar, Belle).
• LHC (CMS, ATLAS, LHC-b).
• Linear Collider (?).
• What could CLEO-c possibly have to offer this
  program?

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• CLEO-c will play three important roles
• We will perform a suite of measurements whose
  results will significantly increase the precision
  of Standard Model tests being done by all
  experiments.
• We will directly probe physics within and beyond
  the Standard Model.
• We perform a comprehensive experimental study of
  non-perturbative QCD.

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• Measurements that will enable precision
  Standard Model tests by us as well as other
  experiments
• fD and fDs at 2 level.
• Keystone absolute hadronic charm branching ratios
  with 1-2 errors.
• Precision form-factors in semileptonic P?P and
  P?V decays (few accuracy).
• Lengthy list of exclusive charm semileptonic
  branching fractions with 1-2 errors.

1.
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Goal for this decade high precision measurements
of Vub, Vcb, Vts, Vtd, Vcs, Vcd, and associated
phases. Over-constrain the various Unitarity
Triangles - Inconsistencies ? New Insights
! Many experiments will contribute to
these measurements. CLEO-c will enable precise
new measurements to be translated into greatly
improved CKM precision!
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Flavor Physics
CLEO-c will improve precision Example
Length of this side
Lattice predicts fB/fD fBs/fDs with small
errors. If precision measurements of fD fDs
existed (i.e. CLEO-c), we could obtain precision
estimates of fB fBs. This is also needed for
precision determinations of Vtd and
Vts. Similarly, fD/fDs checks LQCD fB/fBs
calcultation.
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fDs from Absolute Br(Ds ? mn)

• Measure absolute Br (Ds ? mn)
• Fully reconstruct one D (tag)
• Require one additional charged track and no
  additional photons.
• Compute MM2

MC
Ds ? mn
Vcs, (Vcd) known from unitarity to 0.1 (1.1)
Reaction Energy(MeV) L fb-1 PDG CLEO-c
f Ds Ds ? mn 4140 3 17 1.7
f Ds Ds ? tn 4140 3 33 1.6
f D D ? mn 3770 3 UL 2.3
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The importance of absolute Charm BRs
Vcb from zero recoil in B ? Dl?
CLEO LP01
Stat 3.1 Sys 4.3 theory 4.6 Dominant Sys
??slow, form factors
B(D?K?) dB/B1.3
Vub/Vcb from at
hadron machines requires

B(/\c?pKp) poorly known 9.7 gt B gt3.0 at 90
C.L
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The importance of absolute Charm BRs

• HQET spin symmetry test

Test factorization with B ? DDs
Understanding charm content of B decay (nc)
Precision Z ?bb and Z ?cc (Rb Rc)

At LHC/LC H ? bb H ? cc
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Absolute Branching Ratios
Zero background in hadronic tag modes Measure
absolute Br (D? X) with double tags Br of X/
of D tags
MC
CLEO-c sets absolute scale for all heavy quark
measurements
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Compare B factories CLEO-C
CLEO-c 3 fb-1
BaBar 400 fb-1
Current
abcdefghi
Statistics limited
Systematics Background limited

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Semileptonic Form Factors.
VCKM2
f(q2)2

Absolute magnitude shape of form factors is a
great test of theory.
?
B
l ?
i.e.
u
b
HQET
?
l ?
D
c
d
1) Measure D?? form factor in D??l? (CLEO-c)
Calibrate LQCD to 1. 2) Extract Vub at
BaBar/Belle using calibrated LQCD calc. of B??
form factor. 3) Precise (5) Vub is a vital CKM
cross check of sin2?. 4) Absolute rate gives
direct measurements of Vcd and Vcs.
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Semileptonic dB/B, Vcd, Vcs
D0 ?pln
D0 ?Kln
Use CLEO-c validated lattice B
factory B?r/p/h/lv for ultra precise Vub
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2.

• CLEO-c Standard Model tests
• 1-2 measurements of Vcd and Vcs.
• D??l? / D?Kl? semileptonic analyses.
• Mixing sensitivity at the 1 level.
• CP violation sensitivity at the 1-2 level.
• A variety of rare D decays at the 10-6 level.

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Charm Mixing
Consider time integrated ratios of rates to
various final states.
See hep-ph/0103110Gronau, Grossman Rosner
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Charm Mixing
One example (many to choose from)
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CP Violation
ee- ? ? ? D0D0
JPC 1--
i.e. CP
Suppose both D0s decay to CP eigestates f1 and
f2 These can NOT have the same CP
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3.

• Comprehensive study of non-perturbative QCD
• ? and ? spectroscopy.
• Masses fine structure.
• Leptonic width of S states.
• EM transition matrix elements.
• New forms of matter
• Glueballs (gg)
• Hybrids (gqq)

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Gluonic Matter

• Gluons carry color charge should bind!
• CLEO-c 1st high statistics experiment covering
  1.5-2.5 GeV mass range.
• Radiative y decays are ideal
• glue factory

• But, like Jim Morrison, glueballs have been
  sighted
• too many times without confirmation....

Inclusive g spectrum (CLEO-c)
Example fJ(2220)
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Additional topics
Likely to be added to run plan

• ? spectroscopy (10 8 decays) ?chc
• tt- at threshold (0.25 fb-1)
• measure mt to 0.1 MeV
• heavy lepton, exotics searches
• LcLc at threshold (1 fb-1)
• calibrate absolute BR(Lc?pKp)
• Rs(ee- ? hadrons)/s(ee- ? mm-)
• spot checks

If time permits
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CLEO-c Physics Impact (what Snowmass said)

• Crucial Validation of Lattice QCD Lattice QCD
  will be able to calculate with accuracies of
  1-2. The CLEO-c decay constant and semileptonic
  data will provide a golden, timely test. QCD
  charmonium data provide additional benchmarks.
  (E2 SnowmassWG)

Now

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CLEO-c Physics Impact (what Snowmass said)

• Knowledge of absolute charm branching fractions
  is now contributing significant errors to
  measurements involving bs. CLEO-c can also
  resolve this problem in a timely fashion

PDG
Vcd Vcs Vcb Vub Vtd Vts
7 16 5 25 36 39
1.7 1.6 3 5 5 5
B FactoryData withCLEO-c LatticeValidation
CLEO-c data and LQCD
The potential to observe new forms of matter
glueballs, hybrids, etc and new physics- charm
mixing, CP violation, and rare decays
provides a discovery component to the program
Also endorsed by HEPAP.
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Proposal Timeline

• CLEO-C workshop (May 2001) successful
• 120 participants, 60 non-CLEO
• Snowmass working groups E2/P2/P5 acclaimed
  CLEO-c
• HEPAP endorsed CLEO-c
• CESR/CLEO PAC Endorsed CLEO-c (Sept/01)
• Proposal submission to NSF was on October 15.

• Site visit planned for March/02
• Science Board March/02,
• Expect approval shortly thereafter
• See http//www.lns.cornell.edu/CLEO/CLEO-C/
  for project description
• We welcome discussion and new members