Top Quark and W Boson Mass at CDF

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Top Quark and W Boson Mass at CDF

• Young-Kee Kim
• The University of Chicago
• Forth Workshop on Mass Origin and Supersymmetry
  Physics
• March 6-8, 2006
• Tsukuba, Japan

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Origin of Mass
There might be something (new particle?!) in the
universe that gives mass to particles.
Nothing in the universe
Something in the universe
Higgs Particles
Coupling strength to Higgs
is proportional to mass.
Photon Electron Z,W Boson Top Quark
x
x
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The importance of MW and Mtop

• Precision Electroweak Measurements
• probe the Higgs bosons indirectly
• by means of quantum corrections.

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Quantum Corrections

• Large quantum corrections to Electroweak
  observables come from the top quark.

top top
top bottom
W
Z
Different quantum corrections to MW and MZ
With precision (better than 1) MW, MZ, cos?W
measurements, we can predict top quark mass.
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Mtop Measurements vs. Prediction
Top Mass Prediction from the global fit to EW
observables
Direct measurements from CDF and D0
Limits from direct searches with ee- and pp
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Quantum Corrections

• Secondary contributions are from the Higgs.
• MW MW0 C1 Mtop2 C2 ln(MHiggs2)

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MW - Mtop - MHiggs
Higgs Mass Will the Tevatrons prediction agree
with what LHC measures?
(LP05)
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Importance of MW and Mtop in MSSM
Additional quantum corrections from SUSY partners
(Summer 05)
Higher precision MW and Mtop measurements will
enable to distinguish between the Standard Model,
Light SUSY, and Heavy SUSY
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Importance of Mtop in MSSM
G. Degrassi, S.. Heinemeyer, W. Hollik, P.
Slavich, G. Weiglein Eur. Phys. Jour. C28 (2003)
133, hep-ph/0212020
Mtop
Mtop plays a key role in determining Mh in MSSM.
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You should go to the masseslearn from them,
andsynthesize their experienceinto better,
articulated principles andmethods, . - Mao
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Tevatron Performance (Run II)
Peak Luminosity
Int. Lum. (delivered) / Experiment
2002 2003 2004 2005
2002 2003 2004 2005
shutdown

• Peak luminosity record 1.8 ? 1032 cm-2 s-1
• Integrated luminosity
• weekly record 27 pb-1 / week / expt
• total delivered 1.5 fb-1 / expt, total recorded
  1.3 fb-1 / expt
• Doubling time 1 year
• Future 2 fb-1 by 2006, 4 fb-1 by 2007, 8 fb-1
  by 2009

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Tevatron Detectors
CDF
DZero
Excellent Detectors - tracking, b-tagging,
calorimeter, muon CDF Strength momentum
resolution and particle ID(K,?) DZero Strength
muon coverage and energy resolution
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Tevatron MW and Mtop Status in Lepton-Photon 2005
W Mass
Top Mass Tevatron Run I
(110 pb-1) Tevatron Run
I (110 pb-1)
Run
II (320-350 pb-1)
Run I
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W Mass Measurements
W Z
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Lepton Momentum and Energy Scale

• Understand passive material well
• Flatness of J/? ????- mass
• over a large pT range
• E/p tail - data vs. simulation
• ??MJ/? 0.05 MeV
• ???MB 0.2 MeV

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Run II MW Status
Run II W ? e?
Run II W ? ??
Data MC
W Transverse Mass GeV/c2
W Transverse Mass GeV/c2
Run II 200 pb-1 (Run Ib 90 pb-1)
Integrated Luminosity fb-1
Uncert.Source e? II (Ib) ?? II(Ib)
Statistics 45 (65) 50(100)
e/? p Scale 70 (80) 30 (87)
Recoil Energy 50 (37) 50 (35)
Backgrounds 20 (5) 20 (25)
Prod. Decay 30 (30) 30 (30)
Total 105(110) 85(140)
?MW MeV
CDF Run II
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Top Mass Measurements
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Mtop Analysis Method Template

• Select jet-parton assignment that gives the best
  ?2
• for M(2 jets) MW and M(top) M(anti-top)
• Reconstruct top mass
• tt-bar MC templates with different Mtop values
• background templates
• data
• Perform maximum likelihood fit to extract
  measured mass.

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Mtop Analysis Method Matrix Element
Each curve is a probability function from one
Monte Carlo event.

• Originally proposed in 1988 by Kuni Kondo
• J. Phys. Soc. 57, 4126
• For each event,
• All jet-parton assignments are considered and
  weighted by comparing that to the leading order
  Matrix element calculation.
• A probability distribution is produced.

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Jet Energy Determination

• Jet energy resolution
• 84/vET
• Statistical uncertainty
• Jet energy scale
• 3 for jets from top decay
• Dominant systematic uncertainty
• New technique in Run II
• In-situ calibration
• using W ? 2 jets mass
• in leptonjets channel

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Mtop in leptonjets Template (680 pb-1)
Tsukuba group (Shinhong Kim, Taka Maruyama,
Tomonobu Tomura, Koji Sato) has been playing
key roles!!
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Mtop in leptonjets and dilepton Channels
Leptonjets Dilepton
Template
Matrix Element
Mtop (template) 173.4 2.5 (stat. jet E)
1.3 (syst.) GeV Mtop (matrix element) 174.1
2.5 (stat. jet E) 1.4 (syst.) GeV
Mtop (matrix element) 164.5 4.5 (stat.) 3.1
(jet E. syst.) GeV
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Mtop Uncertainty (Run II)
CDF Run II Preliminary
Source of Uncertainty leptonjets Template (680 pb-1) leptonjets Matrix Element (680 pb-1) dilepton Matrix Element (750 pb-1)
Statistics / Jet Energy Scale 2.5 2.5 4.5 / 2.6
Residual / Bgrnd Jet E Scale 0.8 0.42
Monte Carlo Statistics 0.3 0.04
Monte Carlo Generators 0.2 0.19 0.5
Initial State Gluon Radiation 0.5 0.72 0.5
Final State Gluon Radiation 0.2 0.76 0.5
Parton Distribution Functions 0.3 0.12 0.6
b-tagging 0.1 0.31
b jet Energy Scale 0.6 0.60
Background Modeling 0.5 0.21 1.1
Total 2.8 2.9 5.5
CDF Combined MtopCDF 172.0 1.6 2.2 GeV
172.0 2.7 GeV
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Mtop in ljets using Decay Length Technique

• B hadron decay length
• ? b-jet boost
• ? Mtop
• Difficult
• Measure slope of exponential
• But systematics dominated by tracking effects
• Small correlation with traditional measurements
• Statistics limited now
• Can make significant contribution at LHC

Mtop (Lxy) 183.9 15.7-13.9 (stat.) 5.6
(syst.) GeV
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Other CDF Mtop results (318 - 360 pb-1 data
through Aug. 04)

• Three template-style analyses in dilepton channel
• Combined result (340 - 360 pb-1)
• 170.1 6.0(stat.) 4.1(syst.) GeV
• Dynamical Likelihood method (Matrix Element)
• Leptonjets (318 pb-1)
• 173.2 2.6-2.4(stat.) 3.2(syst.) GeV
• (Kohei Yoritas Ph.D. Thesis)
• Dilepton (340 pb-1)
• 166.6 7.3-6.7(stat.) 3.2(syst.) GeV
• (Ryo Tsuchiyas Ph.D. Thesis)

63 events joint likelihood
All consistent with more recent measurements
reported here.
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Tevatron Top Mass Results
Summer 2005
New since Summer 2005
Dilepton
CDF-II MtopME 164.5 5.5
GeV LeptonJets
CDF-II MtopTemp 174.1 2.8 GeV
CDF-II MtopME 173.4 2.9 GeV CDF Combined
MtopCDF 172.0
1.6 2.2 GeV 172.0 2.7 GeV
Updated CDF DØ combined result is coming!
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Electroweak Projections
CDF Run II
CDF Run II
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Comments on Projections (e.g. Mtop)
CDF Top Mass Uncertainties
Run I Measured 110 pb-1
Run II (2fb-1) Projections in 1996
Run II Measured
318 pb-1
680 pb-1
Run II (8fb-1) Projections In 2005
Int. Lum pb-1
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MW, Mtop and Mhiggs in Tevatron/LHC/ILC
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Conclusions

• W Mass
• 1st Run II meas. - coming soon (by this summer)
  - better than Run I
• Top Mass
• MtopCDF 172.0 2.7 GeV/c2 (680 pb-1)
• CDF surpassed 2 fb-1 Run II goal of 3 GeV/c2
• Significant improvements in analysis techniques
• Matrix element method, in situ jet energy
  calibration
• Tevatron measurements in the LHC era
• By LHC turn-on, we expect ?Mtop2 GeV, ?MW30
  MeV.
• By the end of this decade, ?Mtop1.5 GeV, ?MW20
  MeV
• Comparable to LHC measurements
• Most likely be the best for quite some time.
• Higgs mass
• Will Tevatrons prediction agree with LHCs
  direct measurement?

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BACKUP
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MW Luminosity Effects
Effects of higher instantaneous luminosity on
uncertainty
? Transverse Momentum
W Transverse Mass
e, ?? Lepton Transverse Momentum