M Cremonesi - Moriond QCD - March 22, 2015

Recent Top Quark Properties Results from the Tevatron

Matteo Cremonesi FNAL

Accelerator

• Proton-antiproton collider √s = 1.96 GeV

• Two experiments: CDF & D0

• Run II (2001 - 2011) ~10 fb-1/experiment recorded

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Experiments

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Top Discovery

• Discovery announced March 2nd, 1995

• Happy birthday!!!

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Top at Twenty

For more information, visit: http://indico.fnal.gov/event/TopAtTwenty15

Program CommitteeTiziano Camporesi, CERN, SwitzerlandDave Charlton, University of Birmingham, UKMatteo Cremonesi, Fermilab, USADmitri Denisov, Fermilab, USAKeith Ellis, Fermilab, USAPaul Grannis, Stony Brook University, USAAndreas Jung, Fermilab, USAAlison Lister, University of British Columbia, CanadaLuca Malgeri, CERN, SwitzerlandMichelangelo Mangano, CERN, SwitzerlandAndreas Meyer, DESY, Germany

Mark Owen, University of Glasgow, UKDavid Toback, Texas A&M University and Mitchell Institute, USABoris Tuchming, Irfu-CEA Saclay, FranceCostas Vellidis, Fermilab, USAJonathan Wilson, Texas A&M University and Mitchell Institute, USA

Local OrganizersCynthia Sazama, Fermilab, USAMelody Saperston, Fermilab, USASuzanne Weber, Fermilab, USA

Workshop April 9-10, 2015Fermilab, Batavia, IL USA

To celebrate the 20th anniversary of the discovery of the top quark,we will review observations and discoveries made at both

the Tevatron and the LHC, the theoretical context and explorethe indications for physics beyond the standard model.

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Top Quark

• Heaviest know elementary particle

• 174.34 ± 0.76 GeV

• Short lifetime (≈ 5x10-25 s)

• it decays ~ 100% of the times in Wb

• Large Yukawa coupling to the Higgs (~1)

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Properties

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Channels• Strong production of top pairs:

• dominates at the Tevatron

• distinctive kinematic properties

=> S/B ~ 1 or larger

• Channels determined by the W boson decay

τ+τ 1%τ+µ 2%

τ+e 2%

µ+µ 1%

µ+e 2%

e+e 1%

e+jets 15%

µ+jets 15%

τ+jets 15%

"alljets" 46%

"lepton+jets""dileptons"

Top Pair Branching Fractions

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Branching Ratio

Measuring R

• In SM R~1 constrained by CKM unitarity

• In a top-pair production event, 2 b-quarks are expected

=> technique: comparing cross section vs number of b-tags

Measurement of |Vtb|

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R Dileptons

R = 0.87 ± 0.07 (stat.+syst)

|Vtb| = 0.93 ± 0.04 (stat.+syst)

PRL 112 221801

Number of b-tagged jets0 1 2

Num

ber o

f Eve

nts

020406080

100120140160180200

-1Dilepton final state CDF Run II Preliminary 8.7 fbBackgroundsData , R=0.5tt, R=0.87tt, R=1tt

Wq)→BR(t Wb)→BR(t R =

0.07±R = 0.87

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Top Mass

Measuring Top Mass

• Stringent SM self-consistency test

• Precision is crucial

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JES in situ Calibration

• W boson fully reconstructed

• Constrain to the value of the known W boson mass

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Methods

• Matrix Element method: calculate event probability densities using the matrix element of the hard process

• Template method: compares histograms in data to simulations

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• Data driven QCD model, neural network based event selection

• S/B ~1 after selection

• Template method:

• Mtop and MW templates from kinematic fit

Top Mass Alljets/1

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outNN0.5 0.6 0.7 0.8 0.9 1 1.1 1.2

Even

ts/(0

.01)

0

100

200

300

400

500

600

700

800 Data

JES= 0.0)∆, 2=172.5 GeV/ctop

(Mt Bkg + t

Bkg 2 tags events≥

< 1.50out0.50 < NN

)-1 - Preliminary (9.3 fbtopCDF Run II - All Hadronic M

Top Mass Alljets/2

]2 [GeV/crectm

100 150 200 250 300

)2Ev

ents

/(5.0

GeV

/c

0

100

200

300

400

500 1-tag events≥

)-1 Data (9.3 fb

t Fitted Bkg + t Fitted Bkg

)-1 - Preliminary (9.3 fbtopCDF Run II - All Hadronic M

]2 [GeV/crecWm

20 40 60 80 100 120 140 160 180 200 220

)2Ev

ents

/(5.0

GeV

/c

0

100

200

300

400

500

600

700

800

900 1-tag events≥

)-1 Data (9.3 fb

t Fitted Bkg + t Fitted Bkg

)-1 - Preliminary (9.3 fbtopCDF Run II - All Hadronic M

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Mtop = 175.07±1.58(stat)±1.15(syst) GeV (1.1% rel. unc.)

PRD 90 09110116

Top Mass Dileptons\1

• Template method:

Mhyb = wMtreco + (1-w)Mlbalt

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Top Mass Dileptons\2

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Mtop = 171.5 ± 1.9 (stat) ± 2.5(syst) GeV (1.9% rel. unc.)

CDF Conf. Note 1107218

Top Mass CDF Combination

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)2 (GeV/ctM150 160 170 180 190 200

0

11

CDF March’07 2.66± 12.40 2.20)±1.50 ±(

CDF combination * 0.93± 173.16 0.74)±0.57 ±( syst)± stat ±(

CDF-II MET+jets 1.85± 173.93 1.35)±1.26 ±(

CDF-II track 9.46± 166.90 2.90)±9.00 ±(

CDF-II alljets * 1.96± 175.07 1.56)±1.19 ±(

CDF-I alljets 11.51± 186.00 5.70)±10.00 ±(

CDF-II lepton+jets 1.11± 172.85 0.98)±0.52 ±(

CDF-I lepton+jets 7.36± 176.10 5.30)±5.10 ±(

CDF-II dilepton * 3.25± 170.80 2.69)±1.83 ±(

CDF-I dilepton 11.41± 167.40 4.90)±10.30 ±(

Mass of the Top Quark(* CDF preliminary)March 2014

/dof = 5.6/7 (58%)2χ

0.58% rel. unc., CDF Conf. Note 1108019

Top Mass Lepton+jets\1

• ME measurement

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Top Mass Lepton+jets\2

• Systematic uncertainties:

• improved object IDs (e, µ, b)

• new detector calibration

• Measure ratio of b-jets to light jets

=> cross-check of b-JES on data

• increase in MC statistics

=> statistical component 0.25 → 0.05 GeV

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Top Mass Lepton+jets\3

• 2D likelihood fit to extract KJES and mt

• most precise single measurement (0.43% rel. unc.)

• PRL 113 032002 (2014)

• PRL "Editors' Suggestion”

• Nature "News and Views"

• Long write-up sub. to PRD, arXiv:1501.07912

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Top Mass Tev Combination

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)2 (GeV/ctM150 160 170 180 190 200

0

15

CDF March’07 2.66± 12.40 2.20)±1.50 ±(

Tevatron combination * 0.64± 174.34 0.52)±0.37 ±( syst)± stat ±(

CDF-II MET+Jets 1.85± 173.93 1.36)±1.26 ±(

CDF-II track 9.43± 166.90 2.82)±9.00 ±(

CDF-II alljets * 1.95± 175.07 1.55)±1.19 ±(

CDF-I alljets 11.51± 186.00 5.70)±10.00 ±(

DØ-II lepton+jets 0.76± 174.98 0.63)±0.41 ±(

CDF-II lepton+jets 1.12± 172.85 0.98)±0.52 ±(

DØ-I lepton+jets 5.31± 180.10 3.60)±3.90 ±(

CDF-I lepton+jets 7.36± 176.10 5.30)±5.10 ±(

DØ-II dilepton 2.80± 174.00 1.49)±2.36 ±(

CDF-II dilepton * 3.26± 170.80 2.69)±1.83 ±(

DØ-I dilepton 12.82± 168.40 3.60)±12.30 ±(

CDF-I dilepton 11.41± 167.40 4.90)±10.30 ±(

Mass of the Top Quark(* preliminary)July 2014

/dof = 10.8/11 (46%)2χ

0.37% rel. unc., arxiv:1407.2682 23

Summary

• 20 years of top quark properties measurements at the Tevatron

• Top quark Tevatron program almost complete

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