CDF Status

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CDF Status

• April 4, 2003
• Luciano Ristori

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The CDF Collaboration


North America
Europe

Asia


3 Natl. Labs 28 Universities 2 Universities
1 Research Lab 6 Universities 1 University 4
Universities 2 Research Labs 1 University 1
University 1 University
4 Universities 1 Research Lab 1 University 3
Universities

• 112 countries
• 59 institutions
• 706 physicists

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Outline

• Overview of detector and offline operations
• Highlights of Run 2 physics analyses
• QCD with jets
• Electroweak physics with W and Z bosons
• Re-discovering the top quark
• Beauty and charm
• New phenomena searches

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Detector and Offline Operations
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The CDF Detector showingRun 2a Upgrades
New L1, L2, L3 Triggers DAQ System Monitoring
Cherenkov Luminosity Monitor
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Store 2271 February 24-25, 2003

Integrated luminosity
delivered recorded

• 10.84 pb-1 delivered
• 10.75 pb-1 written to tape
• 989 eff. for store

DAQ run 16 hours
Time into store
Silicon Detectors integrated quickly after
Tevatron scraping
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commissioning
physics
March 2003
180 pb-1 delivered
March 2002
130 pb-1 recorded (including early data used for
commissioning)

Integrated Luminosity pb-1
85 pb-1 QCD 72 pb-1 EW 56 pb-1 top tagged
90 efficiency
Data Recording Efficiency
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Trigger Table and Rates

• Complete physics trigger table
• 140 triggers (e, m, t, n, g, jets, displaced
  track)
• Dynamically prescaling some hadronic B triggers
  of lower purity
• L1, L2, L3 trigger rates
• With luminosity of 3 x1031 cm-2 s-1
• L1 11.5 kHz
• L2 250 Hz
• L3 50 Hz
• Total trigger dead time lt 1
• L1 rate limitation at 12 kHz
• is being removed

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Central Outer Tracker (COT) used to select high
Pt tracks at L1 Extremely Fast Tracker (XFT)

Use COT axial track segments
XFT Pt turn on
Measured XFT DPt/Pt2 1.65 Measured angular
resolution 5.1 mrad.
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Silicon Trackers

Stable data taking since June shutdown gt90 of
the Silicon is integrated
Sub-detector Running S/N rF (z)
L00 97.0 S/N 101
SVXII 92.5 S/N 141(121)
ISL 89.0 S/N 12/1(121)

• Now working on minimizing
• inefficiency at the beginning of each store
• Error rate
• Upcoming Challenges
• Higher trigger rates
• A good maintenance plan for stable operations in
  the years to come

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Improvement of Silicon Coverage
March 2003
June 2002
z

phi
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Silicon Vertex trigger (SVT) Selects secondary
vertices at L2

Impact parameter distribution
This distribution is the convolution of the
actual transverse size of the beam spot with the
impact parameter resolution of the SVT
sigma 50 um 43 um 25 um
SVT resolution
beam spot size
cm
Impact parameter do measured at L2
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Offline data processing

• L3 Farm 8 output streams split based on L3
  decisions
• 230 dual CPUs, 20 Mbytes/s to tape, event size
  300 Kbytes
• Offline production split into 35 datasets
• 170 dual CPUs, 3-5 seconds/event, event size
  200Kbytes
• 35 datasets split on L3 trigger bits
• Process 5 million events/day sustained, 10
  million/day peak
• Data analysis system
• 300 dual Athlon CPUs (1.4-1.7 MHz) with 100
  Tbytes of disk
• Robotic tape storage (StorageTeK) accessed over
  network
• Data handling via Enstore (tapes) and DCACHE
  (disk)

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Offline data processing

• Monte Carlo event simulation
• Have used excess processing capacity on
  reconstruction farms
• Moving to a distributed model of MC event
  generation in US, UK, Canada, Italy, Germany, )
• Physics analysis for Winter Conferences
• All physics quality data up to January 2003
  shutdown reprocessed

300 million
Red events from DAQ Blue events reconstructed
200 million
Events processed by offline reconstruction
Feb. 2002
Feb. 2003
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Physics Analyses

QCD Electroweak Top Beauty and Charm Exotics
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Integrated Luminosity for Physics

• Total data recorded to tape (130 pb-1) includes
  that taken early in Run 2 when detector was not
  fully commissioned.
• Data acquired over past year 100 pb-1
• As of end of January 2003 Ldt for physics
• Jet measurements 85 pb-1
• High Et electrons 72 pb-1
• Top lepton plus jets with B tags 56 pb-1
• Since October 2002 the silicon detectors are
  integrated into physics data taking 98 of the
  time for clean stores.
• Now working on improving recorded data -gt physics
  data efficiency

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QCD Physics with Jets

• Jet structure
• High Et probes with inclusive jets
• Particle searches with di-jets

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Jet structure

Measure ET with calorimeter towers and tracking
chambers
Study Y(r) and jet energy flow Compare to
PYTHIA(6.203) 2-gt2 processes plus CDF detector
simulation
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Jet structure
Central Jets Good agreement with PYTHIA and
detector simulation
Forward Jets New plug calorimeter Needs some
simulation tuning.

CDF Run II Preliminary
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Inclusive high Et jets
Corrected Et spectra compared to NLO (EKS)
predictions With CTEQ6.1 PDFs

Inclusive jet ET in h bins
CDF Run II Preliminary
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Di-jet studies

Dijet Mass 1146 GeV
ET 528 GeV h -0.55
ET 538 GeV h 0.20
gt 500 GeV cross section larger by x3 Due to
increased COM energy
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Particle Searches with Di-jets

CDF Run II Preliminary
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Electroweak Physics

• W and Z boson production
• e e- forward-backward asymmetry

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W and Z boson inclusive production

• Clean signals of inclusive W and Z bosons are the
  first step in CDFs precision electroweak physics
  program
• Measurements based upon 72 pb-1 of data
• W -gt e n, m n and t n
• Z -gt e e and m m
• The W -gt t n channel allows clean study of tau
  lepton identification

Compare s(W)BR(W-gtt n) to s(W)BR(W-gte
n) gt / ge 0.99 0.04
Charged particle multiplicity from W -gt t
n candidates
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W -gt m n
Z -gt m m

• Backgrounds low
• Detector simulation
• reproduces data

W -gt e n
Z -gt e e
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W, Z production and G(W)
sW BR(W?en) 2.640.01stat0.09syst 0.16lum
nb sW BR(W?mn) 2.640.02stat0.12syst
0.16lum nb sW BR(W?t n) 2.620.07stat0.21syst
0.16lum nb

NNLO Prediction 2.69 nb
sZ BR(Z?ee) 267 6stat 15syst 0.16lum
pb sZ BR(Z?mm) 246 6stat 12syst
0.15lum pb sZ BR(Z?tt) in progress
NNLO Prediction 252 pb
Measure R(e) s(W)BR(W-gte n)/ s(Z)BR(Z-gte e)
and R(m)
G(W) 2.29 0.12 GeV from R(e) G(W) 2.11
0.09 GeV from R(m)
PDG value 2.11 0.04 GeV
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ee- forward-backward asymmetry
Sensitive to new neutral gauge bosons

Data e with Et gt 20 GeV, h lt 3.0
SM ZGRAD, Pythia with CTEQ5L
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Top Physics

• top pair production using eemmem s 0.05
  s(t t)
• top pair production using e, m jets s 0.30
  s(t t)
• first look at top mass in Run 2

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Top physics in Run 2
s 7 pb

85

• Major focus of Run 2
• Worlds knowledge based on 100 events
• Top is special among known particles

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s 3.4 pb
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70
4
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Top studies from di-leptons

• Measurement based on channels with eemmem
  s 0.057pb
• Kinematics selection cuts
• e and m central and isolated with ET gt 20 GeV
• At least 2 jets with ET gt 10 GeV within h lt 2.0
• Missing Et gt 25 GeV
• HT (scalar sum of ET , leptons, jets) gt 200 GeV
• plus various background rejection cuts ( Z veto,
  jets and leptons away from ET )

s(tt) acceptance 0.520.05 Signal/background
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Data 5 events SM tt backg. 2.8 0.3
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Top studies from di-leptons
Di-muon top candidate with a B jet tag

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Kinematics of di-lepton tt candidates
Run 1 p p at 1.80 TeV
Run 2 preliminary p p at 1.96 TeV

• (t t)
• 8.4

s (t t) 13.2 5.9stat 1.5sys
Expect x 1.35
4.5
pb
- 3.5
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Top studies from lepton plus jets

• Measurement based on e and m plus jets channels
  s 0.307pb
• Select W-gte n and m n using standard cuts
• e and m central and isolated with ET gt 20 GeV
• Missing Et gt 20 GeV
• Select jets with ET gt 15 GeV within h lt 2.0
• Use silicon SVXII detector to tag the jets with b
  decays
• Backgrounds determined from data and SM Monte
  Carlo simulations
• Fake Ws
• W bb, W cc and fake tags
• W c
• WW WZ
• Z-gt t t
• Z bb Z cc
• Single top

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Top studies from lepton plus jets
W events with b tagged jets from 57.5 pb-1 of data
Use excess events in gt 3 jets bins to measure the
top cross section

Data 15 events Background 3.8 0.5
s (t t) 5.3 1.9stat 0.8sys 0.8lum
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First Look at top mass in Run 2

• Sample e/m gt 3 jets
• 24 combinations
• 12 correspond to the jet-parton match
• every combination has two solutions for pz?
• with 1 b-tagged jet goes down to 12
• with 2 b-tagged jets to 4
• Impose MtMt , M(j,j)M(l,?)MW,
• 2-C fit applied, lower ?? is chosen for top mass
• Model the shape of the reconstructed top mass
• distribution and the background
• Extract top quark mass using maximum Likelihood

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Top Mass from e/m jets channel
33 events without b-tagging ? 4 jets with
Et gt 15 GeV 13 t t events plus 20 background
events
11 events with a b-tagging 3 jets
Et gt 15, 4th jet Et gt 8 GeV) 9 t t events plus 2
background events

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Heavy Flavor Physics

• Lots of charm particles
• Establishing robust beauty signals

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First CDF Run II PublicationSubmitted

M(Ds-D) 99.28 0.43(stat) 0.27(syst)
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Cabibbo suppressed D0 decays

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Search for FCNC decay D0 ? m m-
Select events using the SVT two-track-trigger
Normalization Do -gt p p-
Blind search for Do -gt m m-

Pt gt 2 GeV/c 120 m lt do lt 1 mm
BR(Do -gt m m-) lt 3.1 x10-6 95 CL (factor of 2
below previous best limit)

• SM prediction
• BR(Do -gt m m-) 10-13
• clean territory for new
• physics search

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B physics basics

t(B) 1.57 0.07 0.02 ps
t(Bo) 1.42 0.09 0.02 ps
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Exclusive beauty meson decays

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B ? h h-
A mixture of Bd ? pp Bd ? Kp Bs ? Kp Bs ? KK
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Bs ? Ds p
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Beauty baryon decays
Lb -gt Lc p-

Lb -gt J/y L
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New Phenomena Searches

• Z
• Randell Sundrum Graviton
• Leptoquarks
• Doubly charged Higgs bosons

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Z and RS-Graviton Search
Run II 650 GeV/c2 Run I 640 GeV/c2
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Lepto-quarks and H
M(LQ) gt 230 GeV/c2 _at_ 95 CL Run I gt 220 GeV/c2 0
events observed (Scalar) LQLQ?eejj
Same sign dielectrons-10 mass bin 0 Events
Observed Background Z,dijet,W/Zjet
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Summary Conclusions

• All detector components are recording physics
  quality data
• Have re-established the Tevatron Collider physics
  program
• Early results demonstrate the broad physics
  potential of Run II
• From charm particles to top quarks and beyond
• Summer Conferences 2003 (Lepton-Photon, etc.)
• Look for many measurements that will supercede
  Run I results