CDF

1
CDF???????

• Yuji Takeuchi (Tsukuba)
• for CDF collaborations
• ?????? ?64?????
• Mar. 28th, 2009

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Tevatron Run IIStill at the Energy Frontier
Chicago
CDF
D0
TEVATRON
MAIN INJECTOR

• Tevatron
• The world's highest-energy particle collider
• Proton-antiproton collisions at vs 1.96 TeV
• Tevatron is performing really well
• Reach 6 fb-1 and 78 fb-1 expected by the end of
  2009.

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The CDF II Detector

• Silicon vertex detector (152 layers)
• Central drift chamber (8 super layers)
• 1.4T solenoid
• Good particle identification (K,p)
• Central/Wall/Plug calorimeters
• Scintillator drift chamber muon detectors

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CDF Collaboration

• 700 physicists from
• 12 nations and 61 institutions

Canada
Spain
USA
McGill Univ. Univ. of Toronto
Argonne National Lab. Baylor Univ. Brandeis
Univ. UC Davis UC Los Angeles UC San Diego UC
Santa Barbara Carnegie Mellon Univ. Univ. of
Chicago Duke Univ. Fermilab Univ. of
Florida Harvard Univ. Univ. of Illinois The Johns
Hopkins Univ. LBNL MIT Michigan State Univ. Univ.
of Michigan Univ. of New Mexico Northwestern
Univ. The Ohio State Univ. Univ. of
Pennsylvania Univ. of Pittsburgh Purdue
Univ. Univ. of Rochester Rockefeller
Univ. Rutgers Univ. Texas AM Univ. Tufts
Univ. Wayne State Univ. Univ. of Wisconsin Yale
Univ.
IFAE, Barcelona CIEMAT, Madrid Univ. of Cantabria
Russia
France
JINR, Dubna ITEP, Moscow
LPNHE, Paris
Germany
Korea
Univ. Karlsruhe
KHCL
Switzerland
Japan
Univ. of Geneva
KEK Okayama Univ. Osaka City Univ. Univ. of
Tsukuba Waseda Univ.
UK
Glasgow Univ. Univ. of Liverpool Univ. of
Oxford Univ. College London
Taiwan
Academia Sinica
Italy
Univ. of Bologna, INFN Frascati, INFN Univ. di
Padova, INFN Pisa, INFN Univ. di Roma,
INFN INFN-Trieste Univ. di Udine
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Tevatron Status

• Continually establishing new records!
• Peak luminosity
• 3.51032 cm-2 s-1
• Weekly integrated luminosity
• 78 pb-1/week
• Annual integrated luminosity
• 1.8 fb-1 (US FY 2008)
• Average pbar accumulation rate
• 211010 pbar/ hour
• Very stable operation
• Maximizing integrated luminosity
• 12 weeks shutdown in 2009 summer

FY08
FY07
FY06
FY05
FY04
FY03
FY02
FY09
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Integrated Luminosity

• Integrated luminosities for each FY
• Extrapolation for FY2009 2 fb-1
• Data taking efficiency
• Typically 85

FY08
FY09
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Tevatron Prospects

• FY2009
• Run continues
• 2 fb-1, total 7 fb-1
• Shutdown 12 weeks from June

• FY2010
• Fermilab plans to run (Budget approved) and
  CDF/DØ are ready
• Another 2.5 fb-1,total ??9 fb-1

9.32 fb-1
9
FY10 start
7.78 fb-1
Highest Int. Lum
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Integrated luminosity (fb-1)
Lowest Int. Lum
1.8 fb-1 delivered in FY08
FY09 start
FY08 start
0
time since FY04
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Physics Programs at Tevatron

• New SM process
• WZ,ZZ, Single-Top, ...
• Top quark physics
• Precise measurement
• W mass, ...
• Heavy flavor phyics
• ?(bb)??50?s
• Higgs search
• Search for new physics
• First exploration of TeV scale

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Top Quark Physics
Single top ?????????????(??)????
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Top Pair production
Dominant process
1020
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Top Pair Signature

• All Hadronic
• 6jet(2bjet)

• LeptonJet
• 1lepton
• 4jet(2bjet)
• MET

• Dilepton
• 2 lepton
• 2 bjet
• MET

• Top quark decays as a bare quark
• Information on spin polarization and momentum is
  directly transferred to decay products

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Top Pair Production Cross-section

• Now better than theoretical uncertainties
• Luminosity is dominant source of uncertainty

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?(ttbar)/?(Z) in lepton jet channel
new

• Event selection
• High PT lepton
• ?3jet, MET
• NN technique
• Trained to separate ttbar from Wjets bkg

• The total uncertainty is decreased by 10 by
  taking the ratio of the top pair to the Z cross
  sections

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Top Quark Mass
update
Goal before Run-II started 3 GeV/c2 with 2
fb-1
0.9 precision!
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Two Breakthroughs in Top Mass Measurements

• in-situ W?jj JES calib.
• JES (jet energy scale) calibration using di-jet
  invariant mass from W
• Incorporate JES into likelihood function
• L(Mt)?L(Mt,JES)
• Turn JES systematics into statistics
• Reduced with statistics of top events

• Matrix Element Method
• Use information on leptons and jets maximally

Observables
Matrix element with a given top mass gives p.d.f.
of observables
Mjj?MW
Likelihood function of top mass for a given set
of observables
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Top Mass Measurement in Lepton Jet channel
update
World Best. Better than 1
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Measurement of ds/dMtt in Lepton Jet channel
update
Response matrix
Reconstructed Mtt
True Mtt vs Recons. Mtt
Unfolding
Unfolded dist.
?/MPl gt 0.16 (95 CL)
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Forward-Backward Asymmetry in ttbar production
LO Afb0 NLO Afb(5 ? 1.5)
Positive Asymmetry
Negative Asymmetry
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Forward-Backward Asymmetry in ttbar production
update
unfolding
2? away from NLO prediction 2.8 ? away from
null asymmetry
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B Physics
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Y(4140) in B ? J/?fK
new

• B?J/?fK is OZI suppressed

Yield 14?5 ?m 1046.3? 2.9 (stat)
MeV/c2 Width 11.7 8.3-5.0 (stat) MeV
Significance 3.8s
Mass 4143.0 ? 2.9 (stat)? 1.2 (syst) MeV/c2
(adding J/? mass) Width 11.7 8.3-5.0 (stat) ?
3.7(syst) MeV JPC?? tentatively name it
as Y(4140)
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SM Higgs Search
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Higgs cross-section and BR
High mass Higgs region mHgt135 GeV/c2 H ? WW
dominant decay. Gluon fusion production search
(gg ? H).
Low mass Higgs region mHlt135 GeV/c2 H ? bb
dominant decay. Search for associated W/Z
production.
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H ?WW ?l ?l- ?
update

• 2 opposite sign leptons MET
• WW from spin 0 higgs
• leptons tend to same direction
• ?fll is best discriminant

• Neural network technique
• ?fll, ?Rll, HT, ...

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H ?WW, WH ?WWW
update

• Also search for same sign leptons for WH ?WWW
  ?l?l ?X
• WH?WWW (2.7fb-1) ? Next talk (???? ???)
• Combine OS0j, OS1j, OS2j, and SS1j
• 95 CL Limit/SM 1.33 (1.45 expected)_at_ MH165
  GeV/c2

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WH?l?bb
???(??)
NN, 1 b-tag
Bkg Wbb, Wcc, Wqq, ttbar, ...

• Neutral network (NN) technique
• Limit lt 5.2 x SM _at_MH115GeV/c2
• Matrix element (ME) Boosted decision tree (BDT)
  technique
• Limit lt 5.24 x SM _at_MH115GeV/c2

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WH?l?bb (Combined)
update

• Updated on Nov 7, 2008
• Combined result of NN and MEBDT
• Improved by 15
• 95 CL Limit/SM 5.6 (4.8 expected) _at_MH115 GeV/c2

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Other Low Mass Higgs Searches

• MET 2b jets
• Limit/SM 5.6
• _at_MH115 GeV/c2

• 2lepton2b-jets
• Limit/SM 7.1
• _at_MH115 GeV/c2

• ? had ? lep2 jets
• Limit/SM 25
• _at_MH115 GeV/c2

???(???)
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CDF Combined Results
update
H?tt
ZH?llbb
WH?WWW
VH?bbMET
H?WW
WH?lnbb

• Updated on Mar 5, 2009
• 95 CL Limit/SM 3.64 (3.22 expected) _at_ MH115
  GeV/c2
• 95 CL Limit/SM 1.46 (1.61 expected) _at_ MH165
  GeV/c2

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Higgs Exclusion _at_ Tevatron
update
CDFDZero combination Updated on Mar 5, 2009
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Projections

• CDFDZero projections assuming they perform the
  same (2xCDF)
• Possible improvements (1.51.6x sensitivity)
• Acceptance, Analysis method, jet/MET
  resolutions, ...
• Good possibility to see 3? evidence to a Higgs of
  165 GeV/c2
• Doesnt take data already analyzed into account.
• Good possibility to see 2 ? excess to low mass
  higgs or to exclude at 95 CL if there is no
  higgs and with improvements.

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Constraining the Higgs boson mass
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Summary

• Tevatron is operating well. Better than ever!
• CDF is ready to run FY2010. ?Ldt gt 9 fb-1 is
  expected.
• CDF is still providing constantly update results
  as well as new topics.
• Top, Bottom, EWK, QCD, Higgs search, BSM search,
  ...
• CDFDØ Higgs exclusion 160-170GeV/c2 (95CL)
• Indirect measurement
• ????CDF???????????????????.
• Wh?WWW ???(????)
• Single top search ???(???)

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Backup
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Higgs Projections (low mass)
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Higgs Projections (High mass)
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What is a Boosted Decision Tree ?
S/B 52/48

• Weight Wi for each event( 1 to start)
• Purity P?Ws/(?Ws ?Wb)
• Split until minimal event reached or limit of
  purity reached
• if PgtPmin signal leaf
• if PltPmin background leaf
• Boosting
• if a signal event is on a bkg leaf or if a bkg
  event is on a signal leaf
• ? weight modified
• Then training re-performed with the new weights

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SM Higgs cross-section
Summer 2008