Top Quark and W Boson Mass at CDF

Top Quark and W Boson Mass at CDFTop 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

4th Workshop on Mass Origin & Supersymmetry: Mar 6-8, 2006, Tsukuba Young-Kee Kim, Univ. of Chicago 2

Nothing in the universe Something in the universe

Higgs Particles:Higgs Particles:Coupling strength to Higgs

is proportional to mass.

xx

x

xxx

x

xx xxx

x

Photon

Electron

Z,W Boson

Top Quark

There might be something (new particle?!) in the universethat gives mass to particles.

Origin of Mass

The importance of MW and Mtop

Precision Electroweak Measurements

probe the Higgs bosons indirectly

by means of quantum corrections.


Quantum Corrections

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

Different quantum corrections to MW and MZ

top

top

top

bottom

W Z

With precision (better than ~1%) MW, MZ, cosW measurements,we can predict top quark mass.


Mtop: Measurements vs. Prediction

Now

Top Mass Predictionfrom the global fit to EW observables

Limits from direct searches with e+e- and pp

Direct measurementsfrom CDF and D0


Quantum Corrections

W

W

top

bottom

Higgs

Secondary contributions are from the Higgs.

MW = MW0 + C1 Mtop

2 + C2 ln(MHiggs2)

Mtop (GeV)

MW

(GeV

)

150 175 200

80.5

80.4

80.3

M higgs

= 1

00 G

eV20

0 GeV

300

GeV50

0 GeV

1000

GeV

Inputs:s, em(MZ

2), MZ

For equal weights in 2 fits for MHiggs,

MW = 0.007 Mtop (Mtop = 2 GeV, MW = 14 MeV)


MW - Mtop - MHiggs

Mtop (GeV)

MW

(GeV

)

150 175 200

80.5

80.4

80.3

Higgs Mass: Will the Tevatron’s prediction agree with what LHC measures?

MHiggs (GeV)

5 D

isco

very

Lum

inos

ity (

fb-1)

hard hard

easy100 200 300 500 800

(LP’05)


Importance of MW and Mtop in MSSM

Additional quantum corrections from SUSY partners

(Summer 05)

Higher precision MW and Mtop measurements will enable to distinguishbetween the Standard Model, Light SUSY, and Heavy SUSY


Importance of Mtop in MSSM

Mtop

G. Degrassi, S.. Heinemeyer, W. Hollik, P. Slavich, G. WeigleinEur. Phys. Jour. C28 (2003) 133, hep-ph/0212020

Mtop plays a key role in determining Mh in MSSM.

LEP2 95%CLSM Higgs Limit

Mtop helps constraining MSSM models.

You should go to the masseslearn from them, and

synthesize their experienceinto better, articulated principles and

methods, ….

- Mao


Tevatron Performance (Run II)

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

2002 2003 2004 2005 2002 2003 2004 2005

Peak Luminosity Int. Lum. (delivered) / Experiment

shutdown

LP’05

Today


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


Tevatron MW and Mtop Status in Lepton-Photon 2005

Run I

W Mass Top MassTevatron Run I (~110 pb-1) Tevatron Run I (~110 pb-1) + Run II (320-350 pb-1)

W Mass Measurements

q

q g

W, Z

q

e, e, e,

W Z


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 MeVMB = 0.2 MeV

p / p = - (0.03 ± 0.01)%

+- mass (GeV) near Upsilon

p / p = - (0.10 ± 0.01)%

pp_

1 / pT(GeV-1)

J/+- mass vs 1/pT

E / p of W electrons

DataMC

p(tracking)

E(EM cal)

beampipe, silicon

e

e

CDF Preliminary


Run II MW StatusRun II W e Run II W

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)

Run II 200 pb-1 (Run Ib 90 pb-1) Integrated Luminosity [fb-1]

MW [M

eV]

CDF Run II

W Transverse Mass [GeV/c2] W Transverse Mass [GeV/c2]

DataMC

Top Mass Measurements

q

q g

t

tq

W+

b

b

W-

g

all jets: 44%

e+jets:15%

+jets: 15%

: 21%

ee,e,: 5%

e/+jets is most powerful Large Br, 1 - better than dilepton Sig / Bgrnd - better than all jetsB tagging Secondary vertex, Jet Prob., Soft e/

b

b

q

q

e+ ,

g


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.


Mtop Analysis Method: Matrix Element

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.

Each curve is a probability functionfrom one Monte Carlo event.


Jet Energy Determination

Jet energy resolution

– 84%/√ET

– 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 lepton+jets channel


Mtop in lepton+jets: Template (680 pb-1)

Tsukuba group(Shinhong Kim, Taka Maruyama, Tomonobu Tomura, Koji Sato)

has been playing key roles!!


Mtop in lepton+jets and dilepton Channels

Mtop (template) = 173.4 ± 2.5 (stat. + jet E) ± 1.3 (syst.) GeVMtop (matrix element) = 174.1 ± 2.5 (stat. + jet E) ± 1.4 (syst.) GeV

Template Matrix Element

Mtop (matrix element) = 164.5 ± 4.5 (stat.) ± 3.1 (jet E. + syst.) GeV

Lepton+jets

Dilepton


Mtop Uncertainty (Run II)

Source of Uncertainty lepton+jets Template

(680 pb-1)

lepton+jets

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 Run II Preliminary

CDF Combined: MtopCDF = 172.0 ± 1.6 ± 2.2 GeV = 172.0 ± 2.7 GeV


Mtop in l+jets 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


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)– Lepton+jets (318 pb-1)

173.2 +2.6-2.4(stat.) ± 3.2(syst.) GeV

(Kohei Yorita’s Ph.D. Thesis)

– Dilepton (340 pb-1)

166.6 +7.3-6.7(stat.) ± 3.2(syst.) GeV

(Ryo Tsuchiya’s Ph.D. Thesis)

63 events joint likelihood

All consistent with more recent measurements reported here.


Tevatron Top Mass Results

Summer 2005

Dilepton: CDF-II Mtop

ME = 164.5 ± 5.5 GeV

Lepton+Jets: CDF-II Mtop

Temp = 174.1 ± 2.8 GeV CDF-II Mtop

ME = 173.4 ± 2.9 GeV

CDF Combined: Mtop

CDF = 172.0 ± 1.6 ± 2.2 GeV = 172.0 ± 2.7 GeV

New since Summer 2005

Updated CDF + DØ combined result is coming!


Electroweak Projections

MW [MeV] MTop [GeV] MHiggs / Mhiggs [%]

Luminosity / Experiment [fb-1] Luminosity / Experiment [fb-1] Luminosity / Experiment [fb-1]

10-1 1 1010-2 10-1 1 10

CDF Run II

CDF Run II


Comments on Projections (e.g. Mtop)

Run I Measured110 pb-1

Run II (2fb-1)Projections

in 1996318 pb-1

680 pb-1

Run IIMeasured

CDF Top Mass Uncertainties

Run II (8fb-1)ProjectionsIn 2005

Mtop = MtopRun I / √ LumRun II / LumRun

Int. Lum [pb-1]

We have been doing much better than we predicted. Data makes us smarter!


MW, Mtop and Mhiggs in Tevatron/LHC/ILC

Conclusions

W Mass: 1st Run II meas. - coming soon (by this summer) - better than Run I

Top Mass: Mtop

CDF = 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 Mtop~2 GeV, MW~30 MeV.

By the end of this decade, Mtop~1.5 GeV, MW~20 MeV

– Comparable to LHC measurements Most likely be the best for quite some time. Higgs mass:

– Will Tevatron’s prediction agree with LHC’s direct measurement?


BACKUP


MW Luminosity Effects

Effects of higher instantaneous luminosity on uncertainty

W Transverse Mass

e, LeptonTransverse Momentum

Transverse Momentum

Documents

Top Quark and W Boson Mass at CDF