[PPT] - Precision Measurement of the W Boson Mass at CDF Bodhitha PowerPoint Presentation

SLIDE 1

Precision Measurement of the W Boson Mass at CDF

Bodhitha Jayatilaka Duke University Particle Physics Seminar University of Birmingham 10th October 2012

SLIDE 2

Birmingham Seminar, 10/10/12 Bo Jayatilaka

Motivation: a picture to start with

The standard model
Describes known particles and

interactions

Does not (yet) verifiably describe
Spontaneous symmetry breaking of

U(1)×SU(2)

Fermion masses
Does not describe gravity

2

SLIDE 3

Birmingham Seminar, 10/10/12 Bo Jayatilaka

Motivation: a picture to start with

The standard model
Describes known particles and

interactions

Does not (yet) verifiably describe
Spontaneous symmetry breaking of

U(1)×SU(2)

Fermion masses
Does not describe gravity
Simple explanation: Higgs mechanism
Explains EWSB and fermion masses
Physical manifestation of Higgs boson

2

SLIDE 4

Birmingham Seminar, 10/10/12 Bo Jayatilaka

Motivation: a picture to start with

The standard model
Describes known particles and

interactions

Does not (yet) verifiably describe
Spontaneous symmetry breaking of

U(1)×SU(2)

Fermion masses
Does not describe gravity
Simple explanation: Higgs mechanism
Explains EWSB and fermion masses
Physical manifestation of Higgs boson
Alternatively: ????

2

SLIDE 5

Birmingham Seminar, 10/10/12 Bo Jayatilaka

Cracking/checking the picture with colliders

1. Direct searches. e.g.:
2. Precision measurements

3

]

2

[TeV/c

D

M

2 2.5 3 3.5 4 4.5 5

(pb) σ

1

10 10

3

10

95% CL Expected limits 95% CL Observed limits Theory prediction LO Theory prediction NLO σ +/- 1 σ +/- 2

CMS Preliminary

=7 TeV s at

1

L dt = 4.7 fb

∫

=2 δ ADD

[GeV]

1

R 200 220 240 260 280 300 ) [pb]

±

µ

±

µ B ( × σ 0.05 0.1 0.15 0.2 0.25 0.3

Observed Limit Expected Limit 1 SD Expected ± 2 SD Expected ± Theoretical

1

DØ Run II, L = 7.3 fb

10 10 2 10 3 10 4 10 5 20 40 60 80 100 120 140 160 180 200 220 Centre-of-mass energy (GeV) Cross-section (pb)

CESR DORIS PEP PETRA TRISTAN KEKB PEP-II

SLC LEP I LEP II

Z W+W-

e+e−→hadrons

SLIDE 6

Electroweak sector of the standard model (SM) is constrained by
These inputs give a prediction of mW
Radiative corrections Δr dominated by top and Higgs loops
Precision measurements of mW and mtop constrain SM Higgs mass

Where should the Higgs be?

Birmingham Seminar, 10/10/12 Bo Jayatilaka

What the W mass tells us

4

sin θ2

W = 1 − m2 W

m2

Z

m2

W =

παem √ 2GF sin2 θW (1 − ∆r)

GF = 1.16637(1) × 10−5 GeV−2

αEM(Q2 = M 2

Z) = 1/127.918(18)

mZ = 91.1876(21) GeV/c2

SLIDE 7

)

2

W boson mass (MeV/c 80000 80100 80200 80300 80400 80500 80600 1.5

World Average (2009)

23 ± 80399

Tevatron

31 ± 80420

D0 II

43 ± 80401

CDF II

48 ± 80413

D0 I

84 ± 80483

CDF I

79 ± 80433

LEP2

33 ± 80376

ALEPH

51 ± 80440

OPAL

53 ± 80416

L3

55 ± 80270

DELPHI

67 ± 80336

Birmingham Seminar, 10/10/12 Bo Jayatilaka

Measurements of MW

State-of-the-art (Jan 2012)
DØ MW=80401±43 MeV [1 fb-1, e]

PRL 103:141801 (2009)

CDF MW=80413±48 MeV [200 pb-1, e+µ]

PRL 99:151801 (2007) PRD 77:112001 (2008)

Combining with LEP ∆MW = 23 MeV
Achieved: exceed precision of e+e- machine

measurements with hadron collider

Goal: match precision of all previous

measurements with single CDF measurement

5

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Birmingham Seminar, 10/10/12 Bo Jayatilaka

The top quark mass

mtop = 173.2 ± 0.9 GeV
Equivalent to ∆mW = 6 MeV on mH fit
mW is limiting factor on mH prediction!

6

)

2

(GeV/c

top

m 150 160 170 180 190 200 15

CDF March’07

2.7 ± 12.4

2.2) ± 1.5 ± (

Tevatron combination *

0.9 ± 173.2

0.8) ± 0.6 ± (

syst) ± stat ± (

CDF-II MET+Jets *

2.6 ± 172.3

1.8) ± 1.8 ± (

CDF-II track

9.5 ± 166.9

2.9) ± 9.0 ± (

CDF-II alljets *

2.1 ± 172.5

1.5) ± 1.4 ± (

CDF-I alljets

11.5 ± 186.0

5.7) ± 10.0 ± (

DØ-II lepton+jets

1.5 ± 174.9

1.2) ± 0.8 ± (

CDF-II lepton+jets

1.2 ± 173.0

1.1) ± 0.6 ± (

DØ-I lepton+jets

5.3 ± 180.1

3.6) ± 3.9 ± (

CDF-I lepton+jets

7.4 ± 176.1

5.3) ± 5.1 ± (

DØ-II dilepton

3.1 ± 174.0

2.5) ± 1.8 ± (

CDF-II dilepton

3.8 ± 170.6

3.1) ± 2.2 ± (

DØ-I dilepton

12.8 ± 168.4

3.6) ± 12.3 ± (

CDF-I dilepton

11.4 ± 167.4

4.9) ± 10.3 ± (

Mass of the Top Quark

(* preliminary)

July 2011

/dof = 8.3/11 (68.5%)

2

Combination does not (yet) include

)

2

(GeV/c

top

M 170.5 171 171.5 172 172.5 173 173.5 174 174.5 175 )

2

(GeV/c

top

M 170.5 171 171.5 172 172.5 173 173.5 174 174.5 175 )

c

(

JES

0.4
0.2

0.2 0.4 0.6

log(L) = 0.5

log(L) = 2.0
log(L) = 4.5
1

CDF II Preliminary 8.7 fb

Impressive results from LHC Single best measurement mtop = 172.8±1.1 GeV [CDF]

SLIDE 9

(GeV)

top

m (GeV)

W

m

< 127 GeV

H

115 < m < 1000 GeV

H

600 < m

155 160 165 170 175 180 185 190 195 80.3 80.35 80.4 80.45 80.5

top

(2009), m

W

68% CL (by area) m & direct Higgs exclusion)

top

, m

W

LEPEWWG (2011) 68% CL (excluding m

Birmingham Seminar, 10/10/12 Bo Jayatilaka

Putting it together

7

As of July 2011: mH = 92+34-26 GeV mH < 161 GeV @95% CL

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Birmingham Seminar, 10/10/12 Bo Jayatilaka

Since then...

8

ATLAS and CMS observe a boson with mass ~125-126 GeV
CDF and DØ see evidence of a boson decaying to bbar
Do precision measurements indicate a Higgs boson with this mass?

SLIDE 11

Analysis strategy

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Birmingham Seminar, 10/10/12 Bo Jayatilaka

The Tevatron at Fermilab

1.96 TeV ppbar collider
Highest energy collider in the world
Typical inst. lumi.: 3x1032 cm-2s-1
2011 LHC: ~3x1033 cm-2s-1
Bunch spacing: 396 ns
2011 LHC: 50 ns
Ceased operations Sep 30, 2011
~12 fb-1 delivered to CDF and DØ
Analysis presented utilizes 2.2 fb-1

10

CDF D0

p-pbar

^

SLIDE 13

.5 1.0 1.5 2.0 .5 1.0 1.5 2.0 2.5

SVX Intermediate Silicon Layers

m

3.0

End Wall

Had. Cal.

3 3 0

= 1.0 = 2.0 = 3.0 n n n m

End Plug Hadron Calorimeter

End Plug EM Cal. Central Outer Tracker 1.4 Tesla Solenoid

Birmingham Seminar, 10/10/12 Bo Jayatilaka

CDF II (2001-2011)

11

Central EM calorimeter Central hadronic calorimeter Muon drift chambers

n = 1.0

(COT)

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Birmingham Seminar, 10/10/12 Bo Jayatilaka

Precision?

Start with clean, low-background events
i.e., no taus, no hadronic decays
Lepton pT carries most information
Precision achieved: 0.01%
Hadronic recoil affects inference of neutrino energy
Calibrate to ~0.5%
Reduce impact by requiring pT(W) << MW
Need:
Accurate theoretical model
Including boson pT model and QED radiation
Tunable fast simulation
Parameterized detector description for study of

systematic effects

Large data samples of well-measured states
Various dimuon resonances
Z boson

12

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Birmingham Seminar, 10/10/12 Bo Jayatilaka

Measurement strategy (broadly speaking)

Maximize internal constraints and cross-checks
Why?
1. Robustness: Constrain the same parameter multiple ways
2. Precision: After demonstrating 1), combine independent measurements

13

SLIDE 16

Perform COT alignment with cosmic ray data
Calibrate track momentum scale using dimuon

resonances (J/ψ, Υ).

Cross-check with Z mass measurement and

add as further calibration point

Calibrate calorimeter energy using E/p of W and Z

decays

Cross-check with Z mass measurement
Calibrate hadronic recoil with Z decays to µ, e
Cross-check with W recoil distributions
Perform fits to e/µ pT, ν pT, and transverse mass
Binned maximum likelihood fit to templates from

tuned simulation

Combine all six fits to yield final answer

Birmingham Seminar, 10/10/12 Bo Jayatilaka

Measurement strategy (more specifically)

14

mT =

2p⇤

T p T (1 − cos ∆θ⇤)

(GeV)

T

m 60 65 70 75 80 85 90 95 100 0.005 0.01 0.015 0.02 0.025

80 GeV 81 GeV

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Birmingham Seminar, 10/10/12 Bo Jayatilaka

Selecting W (and Z) bosons at CDF

15

Select eν and µν decays with high-pT lepton trigger Production dominated by qq (~80%) Lepton candidates: Electron ET>30 GeV (track pT>18 GeV)

r Muon pT>30 GeV

W boson candidates: 1 lepton passing cuts |u| < 15 GeV pTv > 30 GeV 60 < mT < 100 GeV Z boson candidates: 2 lepton passing cuts 66 < mll < 116 GeV Analysis dataset: 2.2 fb-1 Candidate events: W: 470126 (e), 624708 (µ) Z: 16134 (e), 59738 (µ)

SLIDE 18

Theoretical model

SLIDE 19

ee) (GeV)

(Z

T

p 5 10 15 20 25 30 events / GeV 200 400 600 800 1000 1200 1400 1600 1800 data 0.052 GeV ± = 8.856 µ 0.037 GeV ± = 6.698

1

2.2 fb

L dt
CDF II preliminary

MC = 8.921 GeV µ = 6.693 GeV

/ DoF = 18.7 / 29

2

) (GeV)

µ µ

(Z

T

p 5 10 15 20 25 30 events / GeV 1000 2000 3000 4000 5000 6000 data 0.027 GeV ± = 8.891 µ 0.019 GeV ± = 6.699

1

2.2 fb

L dt
CDF II preliminary

MC = 8.907 GeV µ = 6.676 GeV

/ DoF = 31.9 / 29

2

Birmingham Seminar, 10/10/12

Bo Jayatilaka

Event generation and boson pT

Generator level simulation from RESBOS1
QCD effects, tunable parameters for non-

perturbative regime (low-pT)

QED radiation simulated by PHOTOS2
FSR multiphoton simulation
Fit parameters in boson pT shape
Low pT sensitive to g2
Intermediate-high pT sensitive to αs
Tuning with Z data applied to Ws

17

}∆MW =5 MeV

Data Simulation Data Simulation

1C Balazs and C-P Yuan, PRD 55, 5558 (1997) 2P

. Golonka and Z. Was, Eur. J. Phys. C 45, 97 (2006)

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Birmingham Seminar, 10/10/12 Bo Jayatilaka

QED Radiation

Extensive studies of QED effects using HORACE1
Leading log approximation vs. exact single photon

calculation

Multi-photon calculations
Higher-order soft/virtual corrections
e+e- pair creation
ISR/FSR interference
Dependence on electroweak parameters/scheme
Detailed comparison of HORACE and PHOTOS
Use PHOTOS in final model
Total systematic uncertainty due to QED ∆MW = 4 MeV
c.f. ∆MW=11 MeV in 200/pb measurement

(uncertainty dominated by subleading photons)

18 HORACE PHOTOS HORACE PHOTOS

1C.M. Carloni Calame, G. Montagna, O. Nicrosini and A. Vicini, JHEP 0710:109 (2007)

SLIDE 21

Tracker alignment

SLIDE 22

Birmingham Seminar, 10/10/12 Bo Jayatilaka

COT alignment with cosmic rays

COT consists of ~30k wires organized

into ~2400 “cells”

Accurate measure of wire positions

crucial for precision track pT

Use in-situ cosmic ray data for

alignment

Fit of COT hits on either side of

vertex to single helix

A. Kotwal, H. Gerberich, C. Hays,

NIM A 506, 110 (2003)

20

SLIDE 23

Cell number (φ) Before alignment

CDFII preliminary

Birmingham Seminar, 10/10/12 Bo Jayatilaka

Tracker alignment

Improve relative alignment precision from ~50µm to ~2µm

21

After alignment

25

25

SLIDE 24

Track momentum scale

SLIDE 25

)

1

> ( GeV

µ T

<1/p 0.2 0.4 0.6 p/p

0.0016
0.0014
0.0012
0.001
1

2.2 fb

L dt
CDF II preliminary
3

10 × 0.022) ± Scale correction = (-1.299 GeV

5

10 × 6.4) ± Slope = (0.8 data µ µ

J/

(GeV)

µ µ

m 3 3.2 3.4 events / 2.5 MeV 5000 10000

3

) x 10

stat

0.024 ± p/p = (-1.284

/dof = 95 / 86

2

1

2.2 fb

L dt
CDF II preliminary

Birmingham Seminar, 10/10/12 Bo Jayatilaka

Track momentum scale: J/ψ

Utilize large samples of µµ resonances (J/ψ, Υ, Z) to set overall scale
Size of J/ψ sample allows subsample fits
Fit J/ψ mass in bins of <1/pT(µ)> and apply material scale calibration (4%)

to remove dependence

Apply calibration from J/ψ to Υ

23 Data Simulation

SLIDE 26

(GeV)

µ µ

m 9 9.5 10 events / 7.5 MeV 5000 10000 15000

3

) x 10

stat

0.02 ± p/p = (-1.185

/dof = 48 / 38

2

1

2.2 fb

L dt
CDF II preliminary

(GeV)

µ µ

m 9 9.5 10 events / 7.5 MeV 5000 10000 15000

3

) x 10

stat

0.025 ± p/p = (-1.335

/dof = 59 / 48

2

1

2.2 fb

L dt
CDF II preliminary

Birmingham Seminar, 10/10/12 Bo Jayatilaka

Track momentum scale: Υ

Υ sample provides higher-pT sample
Υs produced promptly: validation of beam-constraining (BC) procedure
Perform fit with BC and non-BC tracks
Take average of two fits, assign systematic
Combine J/ψ and Υ scales and apply to Zs

24 Data Simulation Data Simulation

Beam constrained tracks Non-beam constrained tracks

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Birmingham Seminar, 10/10/12 Bo Jayatilaka

Track momentum scale: systematic uncertainties

Dominated by QED and B-field non-uniformity
BC vs NBC comparison contributes additional 0.036x10-3

25

Source J/ψ (·10−3) NBC-Υ (·10−3) common (·10−3) QED 0.080 0.045 0.045 B field non-uniformity 0.032 0.034 0.032 Ionizing material 0.022 0.014 0.014 Resolution 0.010 0.005 0.005 Backgrounds 0.011 0.005 0.005 Misalignment 0.009 0.018 0.009 Trigger efficiency 0.004 0.005 0.004 Fitting window 0.004 0.005 0.004 ∆p/p step size 0.002 0.003 World-average 0.004 0.027 Total systematic 0.092 0.068 0.058 Statistical 0.004 0.025 Total 0.092 0.072 0.058

SLIDE 28

Birmingham Seminar, 10/10/12 Bo Jayatilaka

Track momentum scale: systematic uncertainties

Dominated by QED and B-field non-uniformity
BC vs NBC comparison contributes additional 0.036x10-3

25

Source J/ψ (·10−3) NBC-Υ (·10−3) common (·10−3) QED 0.080 0.045 0.045 B field non-uniformity 0.032 0.034 0.032 Ionizing material 0.022 0.014 0.014 Resolution 0.010 0.005 0.005 Backgrounds 0.011 0.005 0.005 Misalignment 0.009 0.018 0.009 Trigger efficiency 0.004 0.005 0.004 Fitting window 0.004 0.005 0.004 ∆p/p step size 0.002 0.003 World-average 0.004 0.027 Total systematic 0.092 0.068 0.058 Statistical 0.004 0.025 Total 0.092 0.072 0.058

∆MW ~ 6 MeV

SLIDE 29

(GeV)

µ µ

m

70 80 90 100 110

events / 0.5 GeV

2000 4000

) MeV

stat

12 ± = (91180

Z

M /dof = 30 / 30

2

1

2.2 fb

L dt
CDF II preliminary

Birmingham Seminar, 10/10/12 Bo Jayatilaka

Muon Z mass measurement

Perform independent measurement of Z mass using tuned momentum scale
Fit central value kept blind during scale calibration
MZ = 91180±12stat±9p-scale±5QED±2alignment=91180±16 MeV
Excellent agreement with world average (91188±2 MeV)

26

SLIDE 30

Birmingham Seminar, 10/10/12 Bo Jayatilaka

Final momentum scale

Add Z data as final calibration point for momentum scale
∆p/pfinal = (-1.29±0.07stat±0.05QED±0.02align)×10-3
Apply scale to W muons and E/p calibration
Systematic uncertainty ∆MW = 7 MeV

27

)

1

> (GeV

µ T

<1/p 0.2 0.4 0.6 p/p

0.002
0.0015
0.001
1

2.2 fb

L dt
CDF II preliminary

data (stat. only) µ µ

J/

data (stat. only) µ µ

data (stat. only)

µ µ

Z

events

µ
syst.) for W
p/p (stat.
combined

SLIDE 31

EM calorimeter scale

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Birmingham Seminar, 10/10/12 Bo Jayatilaka

Simulation for electrons and photons

EM energy loss studied using detailed

GEANT4-based simulation

Leakage into hadronic calorimeter
Absorption into coil
Dependence on incident angle and ET
Improved model of Landau-Pomeranchuk-

Migdal (LPM) suppression of bremsstrahlung

Sophisticated material map for tracker

region of detector

29

SLIDE 33

)

e
E/p (W

1 1.2 1.4 1.6

events / 0.01

10000 20000

/dof = 18 / 22

2

1

2.2 fb

L dt
CDF II preliminary

)

e
E/p (W

1 1.2 1.4 1.6

events / 0.33

100 200 300

3

10 ×

/dof = 1.4 / 1

2

1

2.2 fb

L dt
CDF II preliminary

Birmingham Seminar, 10/10/12 Bo Jayatilaka

Energy scale calibration

Calibrate EM calorimeter response using W and Z E/p distributions
Fit to peak to obtain scale (central value of 1 by construction)
∆SE = (9stat±5non-linearity±5mat±9p-scale)×10-5
Fit to tail to tune amount of radiative material
Apply scale factor to material model SX0=1.026±0.003stat±0.002bkg
Systematic uncertainty ∆MW=13 MeV

30 Data Simulation Data Simulation

SLIDE 34

)

e
(e) (GeV) (W

T

E

30 32 34 36 38 40 42 44 46 48

E

S

0.998 0.999 1 1.001 1.002

1

2.2 fb

L dt
CDF II preliminary

/dof = 6.8 / 5

2

ee)
(e) (GeV) (Z

T

E

30 32 34 36 38 40 42 44 46 48 50

E

S

0.996 0.998 1 1.002

1

2.2 fb

L dt
CDF II preliminary

/dof = 5.6 / 3

2

Birmingham Seminar, 10/10/12

Bo Jayatilaka

EM scale non-linearity

Fit E/p in bins of electron ET
Parameterize non-linearity as SE = 1 + β log(ET/39 GeV)
Tune using W and Z data and obtain β = (5.2±0.7stat)x10-3
∆MW = 4 MeV
Obtain flat response in ET after tuning

31

SLIDE 35

Birmingham Seminar, 10/10/12 Bo Jayatilaka

Electron Z mass and final EM energy scale

Perform independent measurement of Z mass using calibrated EM scale
MZ = 91230±30stat±10E/p±8p-scale±5QED±2alignment=91230±33 MeV
Excellent agreement with world average MZ = 91188±2 MeV
Combine E/p calibration with MZ to obtain final EM calibration
Systematic uncertainty ∆MW =10 MeV

32

(GeV)

ee

m

70 80 90 100 110

events / 0.5 GeV

500 1000

) MeV

stat

30 ± = (91230

Z

M /dof = 42 / 38

2

1

2.2 fb

L dt
CDF II preliminary

Data Simulation

SLIDE 36

(GeV)

ee

track m

70 80 90 100 110

events / 0.5 GeV

200 400

) MeV

stat

47 ± = (91268

Z

M /dof = 62 / 46

2

1

2.2 fb

L dt
CDF II preliminary

Birmingham Seminar, 10/10/12 Bo Jayatilaka

Z mass with electron tracks

Measurement made with only track momenta of Z electrons
Validates material model and application of momentum scale to high-pT

electron tracks

33

SLIDE 37

Muons
Track resolution determined by uncertainty on beamspot size (35±1 µm)

and track hit resolution (150±1 µm)

Tuned using widths of Z and Υ peaks
Electrons
EM calorimeter resolution defined by sampling term and constant term
Constant term tuned using E/p distribution κ = (0.58±0.05)%
Apply secondary constant term for radiative electrons (E/p > 1.1)
κγ =(7.4±1.8)%
Resolution terms total ∆MW = 4 MeV

Birmingham Seminar, 10/10/12 Bo Jayatilaka

Lepton resolution

34

σ/E = 12.6% p ET /GeV ⊕ κ

SLIDE 38

Hadronic recoil

SLIDE 39

Birmingham Seminar, 10/10/12 Bo Jayatilaka

Hadronic recoil: lepton removal

Hadronic recoil u is vector sum of all calorimeter towers minus towers

containing lepton energy

Some underlying event energy removed with “lepton towers”
Estimate using rotated lepton removal windows
Systematic uncertainty ∆MW = 2 MeV

36

12 12 12 12 12 12 12 12 12 11 12 12 11 11 12 12 12 75 12 12 12 12 12 12 1282 14 12 12 12 12 12 406 13 12 12 12 12 12 13 12 11 12 12 12 12 12 12 12 12

3
2
1

1 2 3

3
2
1

1 2 3

Muon Hadronic (MeV)

T

E

Tower
Tower

45 46 46 46 46 45 45 46 46 47 47 47 45 46 46 46 47 164 51 47 46 47 50 63 38443 161 53 48 47 47 50 1219 73 48 47 46 46 47 53 48 47 46 46 46 46 47 47 46 46

3
2
1

1 2 3

3
2
1

1 2 3

Electron Electromagnetic (MeV)

T

E

Tower
Tower

Electron channel W data: Mean EM calorimeter deposition (MeV) Muon channel W data: Mean hadronic calorimeter deposition (MeV)

Central lepton tower Default towers removed

SLIDE 40

Birmingham Seminar, 10/10/12 Bo Jayatilaka

Recoil model

Parametrize recoil model and tune using data
Two components
1. Soft “spectator interaction” component
Randomly oriented (~2 additional interactions per event)
Model using minimum-bias data

2.Hard “jet” component

Boson pT dependent response and resolution
Tune by balancing boson pT and recoil

37

SLIDE 41

ee) (GeV)

(Z

T

p 5 10 15 20 25 30

rec

R 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 / DoF = 35.3 / 29

2

1

2.2 fb

L dt
CDF II preliminary

Birmingham Seminar, 10/10/12 Bo Jayatilaka

Calibrating recoil response

Recoil scale R=umeas/utrue
Calibrate by balancing Z pT against pT+u along

eta axis ∆MW = 4 MeV

38

+

l T

p

l

T

p

ee) (GeV)
(Z

T

p 5 10 15 20 25 30 (GeV)

+ u

Z

0.65p
3
2
1

1 2 3 / DoF = 15.6 / 9

2

1

2.2 fb

L dt
CDF II preliminary

Data Simulation Data Simulation

SLIDE 42

Birmingham Seminar, 10/10/12 Bo Jayatilaka

Calibrating recoil resolution

Recoil resolution
Calibrate balancing Z pT against rms(pT+u)

along both axes ∆MW = 4 MeV

39

) (GeV) µ µ

(Z

T

p 5 10 15 20 25 30 ) (GeV)

+ u

Z

( 0.65p
3.5

4 4.5 5 5.5 6 / DoF = 8.9 / 9

2

1

2.2 fb

L dt
CDF II preliminary

) (GeV) µ µ

(Z

T

p 5 10 15 20 25 30 ) (GeV)

+ u

Z

( 0.65p
3.5

4 4.5 5 5.5 6 / DoF = 7.3 / 9

2

1

2.2 fb

L dt
CDF II preliminary

Data Simulation Data Simulation

+

l T

p

l

T

p

SLIDE 43

) (GeV)

e
(W

u

15
10
5

5 10 15 events / 2 GeV 20 40 60 80 100

3

10 × data 0.007 GeV ± = 0.023 µ 0.005 GeV ± = 5.078

1

2.2 fb

L dt
CDF II preliminary

MC = 0.002 GeV µ = 5.073 GeV

) (GeV)
µ
(W

u

15
10
5

5 10 15 events / 2 GeV 20 40 60 80 100 120 140

3

10 × data 0.006 GeV ± = -0.313 µ 0.004 GeV ± = 4.664

1

2.2 fb

L dt
CDF II preliminary

MC = -0.321 GeV µ = 4.665 GeV

Birmingham Seminar, 10/10/12

Bo Jayatilaka

Recoil validation

Test recoil model with W events
Compare measured recoil in data to model tuned with Z

40

Recoil projection in direction of lepton (muons) Recoil projection perpendicular to lepton (electrons)

Data Simulation Data Simulation

for u ≪ pTl : mT ≈ 2pTl + u||, pTv ≈ 2pTl + 2u||

SLIDE 44

) (GeV)

e
(W

u

15
10
5

5 10 15 events / 2 GeV 20 40 60 80 100

3

10 × data 0.007 GeV ± = 0.023 µ 0.005 GeV ± = 5.078

1

2.2 fb

L dt
CDF II preliminary

MC = 0.002 GeV µ = 5.073 GeV

) (GeV)
µ
(W

u

15
10
5

5 10 15 events / 2 GeV 20 40 60 80 100 120 140

3

10 × data 0.006 GeV ± = -0.313 µ 0.004 GeV ± = 4.664

1

2.2 fb

L dt
CDF II preliminary

MC = -0.321 GeV µ = 4.665 GeV

Birmingham Seminar, 10/10/12

Bo Jayatilaka

Recoil validation

Test recoil model with W events
Compare measured recoil in data to model tuned with Z

40

Recoil projection in direction of lepton (muons) Recoil projection perpendicular to lepton (electrons)

Data Simulation Data Simulation

for u ≪ pTl : mT ≈ 2pTl + u||, pTv ≈ 2pTl + 2u||

15
10
5

5 10 15 2000 4000 6000 8000 10000 12000 Data 0.02 GeV ± = -0.44 µ 0.01 GeV ± = 4.42

MC

0.01 GeV ± = -0.46 µ 0.03 GeV ± = 4.42

||

u

µ
W

(GeV) Events/2 GeV

200 pb-1 [PRD77:112001,2008]

SLIDE 45

Birmingham Seminar, 10/10/12 Bo Jayatilaka

Parton distribution functions

Utilize CTEQ6.6 PDF as default
Evaluate 90% CL uncertainty eigenvectors for MSTW2008 and CTEQ6.6

(consistent)

Use 68% CL MSTW2008 to determine systematic ∆MW=10 MeV

41

Eigenvector

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

)

2

MW (MeV/c Δ

6
4
2

2 4 6

+ e

e

µ + µ

SLIDE 46

Birmingham Seminar, 10/10/12 Bo Jayatilaka

Backgrounds

Electroweak backgrounds (Z→ll, W →τν)
Model using standard CDF detector simulated MC
Tune recoil model and lepton response
QCD backgrounds (hadronic jets, meson decay-in-flight)
Model using control regions in data
Except Z→µµ (lost forward muon), backgrounds are small
Include all estimated background shapes in final templates

42

∆mW (MeV)

W (MeV)

Background Fraction of W data (%) Fraction of W data (%) mT mT pTl pTl pTv pTv Z→ll 7.35±0.09 0.139±0.014 2 1 4 2 5 1 W→τν 0.880±0.004 0.93±0.01 1 1 1 QCD 0.035±0.025 0.39±0.14 1 4 1 2 1 4 Decay-in-flight 0.24±0.02 1 3 1 Cosmic Rays 0.02±0.02 1 1 1 Total 3 4 5 3 6 4

electrons muons

SLIDE 47

Results

SLIDE 48

Birmingham Seminar, 10/10/12 Bo Jayatilaka

A word on blinding

During development of analysis, all fits blinded with random offset from

[-75,75] MeV

Common offset applied to all six mass fits
Allows for comparison and cross-check
During calibration of energy scales, separate offset applied to Z mass fits
Blinding offset removed only after analysis frozen
No changes made since removal

44

SLIDE 49

(e) (GeV)

T

E

30 40 50

events / 0.25 GeV

5000 10000

) MeV

stat

21 ± = (80393

W

M /dof = 60 / 62

2

1

2.2 fb

L dt
CDF II preliminary

) (GeV)

µ

(

T

m

60 70 80 90 100

events / 0.5 GeV

5000 10000 15000

) MeV

stat

16 ± = (80379

W

M /dof = 58 / 48

2

1

2.2 fb

L dt
CDF II preliminary

Birmingham Seminar, 10/10/12 Bo Jayatilaka

Example mass fits

45 Data Simulation Data Simulation

pTl: electrons mT: muons

SLIDE 50

)

2

W boson mass (MeV/c 80100 80200 80300 80400 80500 80600 6.5

T

Electrons: m

26 ± 80408

l T

Electrons: p

28 ± 80393

T

Electrons: p

33 ± 80431

T

Muons: m

23 ± 80379

l T

Muons: p

25 ± 80348

T

Muons: p

30 ± 80406

CDF II

1

L dt = 2.2 fb

Birmingham Seminar, 10/10/12

Bo Jayatilaka

All fits

46

Fit Fit result (MeV) χ2/dof W→eν (mT) 80408±19stat±18syst 52/48 W→eν (pTl) 80393±21stat±19syst 60/62 W→eν (pTν) 80431±25stat±22syst 71/62 W→µν (mT) 80379±16stat±16syst 58/48 W→µν (pTl) 80348±18stat±18syst 54/62 W→µν (pTν) 80406±22stat±20syst 79/62

SLIDE 51

Birmingham Seminar, 10/10/12 Bo Jayatilaka

Combined results

47

Combine using BLUE

L. Lyons, D. Gibaut, and P

. Clifford, NIM A 270, 110 (1988).

SLIDE 52

Birmingham Seminar, 10/10/12 Bo Jayatilaka

Combined results

All electron fits combined

MW = 80406 ± 25 MeV, χ2/dof = 1.4/2 (49%)

47

Combine using BLUE

L. Lyons, D. Gibaut, and P

. Clifford, NIM A 270, 110 (1988).

SLIDE 53

Birmingham Seminar, 10/10/12 Bo Jayatilaka

Combined results

All electron fits combined

MW = 80406 ± 25 MeV, χ2/dof = 1.4/2 (49%)

All muon fits combined

MW = 80374 ± 22 MeV, χ2/dof = 4/2 (12%)

47

Combine using BLUE

L. Lyons, D. Gibaut, and P

. Clifford, NIM A 270, 110 (1988).

SLIDE 54

Birmingham Seminar, 10/10/12 Bo Jayatilaka

Combined results

All electron fits combined

MW = 80406 ± 25 MeV, χ2/dof = 1.4/2 (49%)

All muon fits combined

MW = 80374 ± 22 MeV, χ2/dof = 4/2 (12%)

All fits combined

MW = 80387 ± 19 MeV, χ2/dof = 6.6/5 (25%)

47

Combine using BLUE

L. Lyons, D. Gibaut, and P

. Clifford, NIM A 270, 110 (1988).

SLIDE 55

Birmingham Seminar, 10/10/12 Bo Jayatilaka

Combined uncertainties

48

MW = 80387±12stat±15syst MeV/c2

Source Uncertainty 2.2 fb-1 (MeV) Lepton energy scale 7 Lepton energy resolution 2 Recoil energy scale 4 Recoil energy resolution 4 Lepton removal 2 Backgrounds 3 pT (W) model 5 PDFs 10 QED radiation 4 Total systematics 15 W statistics 12 Total 19

SLIDE 56

Birmingham Seminar, 10/10/12 Bo Jayatilaka

Combined uncertainties

48

MW = 80387±12stat±15syst MeV/c2

Source Uncertainty 2.2 fb-1 (MeV) Uncertainty 0.2 fb-1 (MeV) Lepton energy scale 7 23 Lepton energy resolution 2 4 Recoil energy scale 4 8 Recoil energy resolution 4 10 Lepton removal 2 6 Backgrounds 3 6 pT (W) model 5 4 PDFs 10 11 QED radiation 4 10 Total systematics 15 34 W statistics 12 34 Total 19 48

Statistics limited by control data Theory based (external inputs)

SLIDE 57

)

2

W boson mass (MeV/c 80000 80100 80200 80300 80400 80500 80600 5.5

Tevatron (preliminary)

16 ± 80387

CDF II

19 ± 80387

D0 II

23 ± 80375

CDF I

79 ± 80433

D0 I

84 ± 80483

Birmingham Seminar, 10/10/12 Bo Jayatilaka

Tevatron and world combinations

49

SLIDE 58

)

2

W boson mass (MeV/c 80000 80100 80200 80300 80400 80500 80600 9.5

World Average (preliminary)

15 ± 80385

CDF II

19 ± 80387

D0 II

23 ± 80375

ALEPH

51 ± 80440

OPAL

53 ± 80416

L3

55 ± 80270

DELPHI

67 ± 80336

CDF I

79 ± 80433

D0 I

84 ± 80483

)

2

W boson mass (MeV/c 80000 80100 80200 80300 80400 80500 80600 5.5

Tevatron (preliminary)

16 ± 80387

CDF II

19 ± 80387

D0 II

23 ± 80375

CDF I

79 ± 80433

D0 I

84 ± 80483

Birmingham Seminar, 10/10/12 Bo Jayatilaka

Tevatron and world combinations

49

SLIDE 59

)

2

W boson mass (MeV/c 80000 80100 80200 80300 80400 80500 80600 9.5

World Average (preliminary)

15 ± 80385

CDF II

19 ± 80387

D0 II

23 ± 80375

ALEPH

51 ± 80440

OPAL

53 ± 80416

L3

55 ± 80270

DELPHI

67 ± 80336

CDF I

79 ± 80433

D0 I

84 ± 80483

)

2

W boson mass (MeV/c 80000 80100 80200 80300 80400 80500 80600 5.5

Tevatron (preliminary)

16 ± 80387

CDF II

19 ± 80387

D0 II

23 ± 80375

CDF I

79 ± 80433

D0 I

84 ± 80483

Birmingham Seminar, 10/10/12 Bo Jayatilaka

Tevatron and world combinations

49

nb: 2009 world average MW = 80399±23 MeV

New CDF measurement significantly exceeds precision of all previous measurements of MW combined!

SLIDE 60

Birmingham Seminar, 10/10/12 Bo Jayatilaka

Sidetrack down memory lane

50

2004 indirect mt and mw 2004 direct mt and mw 1995 direct mt and mw 1995 indirect mt and mw 68% cl

P . Renton, ICHEP 2004

SLIDE 61

Birmingham Seminar, 10/10/12 Bo Jayatilaka

Standard model fit

51

(GeV)

top

m (GeV)

W

m

< 127 GeV

H

115 < m < 1000 GeV

H

600 < m

155 160 165 170 175 180 185 190 195 80.3 80.35 80.4 80.45 80.5

top

(2009), m

W

68% CL (by area) m & direct Higgs exclusion)

top

, m

W

LEPEWWG (2011) 68% CL (excluding m

With MW = 80399±23 MeV MH = 92+34-26 GeV MH < 161 GeV @95% CL LEPEWWG/ZFitter

SLIDE 62

Birmingham Seminar, 10/10/12 Bo Jayatilaka

Standard model fit

51

With MW = 80385±15 MeV MH = 94+29-24 GeV MH < 152 GeV @95% CL LEPEWWG/ZFitter

(GeV)

top

m (GeV)

W

m

< 127 GeV

H

115 < m < 1000 GeV

H

600 < m

155 160 165 170 175 180 185 190 195 80.3 80.35 80.4 80.45 80.5

top

(2009), m

W

68% CL (by area) m

top

(2012), m

W

68% CL (by area) m & direct Higgs exclusion)

top

, m

W

LEPEWWG (2011) 68% CL (excluding m

March 2012

SLIDE 63

Birmingham Seminar, 10/10/12 Bo Jayatilaka

Standard model fit

51

With MW = 80385±15 MeV MH = 94+29-24 GeV MH < 152 GeV @95% CL LEPEWWG/ZFitter

(GeV)

top

m (GeV)

W

m

< 127 GeV

H

115 < m < 1000 GeV

H

600 < m

155 160 165 170 175 180 185 190 195 80.3 80.35 80.4 80.45 80.5

top

(2009), m

W

68% CL (by area) m

top

(2012), m

W

68% CL (by area) m & direct Higgs exclusion)

top

, m

W

LEPEWWG (2011) 68% CL (excluding m

March 2012

(GeV)

top

m (GeV)

W

M

= 125 GeV

H

m

155 160 165 170 175 180 185 190 195 80.3 80.35 80.4 80.45 80.5

top

(2009), m

W

68% CL (by area) M

top

(2012), m

W

68% CL (by area) M & direct Higgs exclusion)

top

, m

W

LEPEWWG (2011) 68% CL (excluding M

July 2012

SLIDE 64

Birmingham Seminar, 10/10/12 Bo Jayatilaka

Standard model fit

51

With MW = 80385±15 MeV MH = 94+29-24 GeV MH < 152 GeV @95% CL LEPEWWG/ZFitter

(GeV)

top

m (GeV)

W

m

< 127 GeV

H

115 < m < 1000 GeV

H

600 < m

155 160 165 170 175 180 185 190 195 80.3 80.35 80.4 80.45 80.5

top

(2009), m

W

68% CL (by area) m

top

(2012), m

W

68% CL (by area) m & direct Higgs exclusion)

top

, m

W

LEPEWWG (2011) 68% CL (excluding m

March 2012

(GeV)

top

m (GeV)

W

M

= 125 GeV

H

m

155 160 165 170 175 180 185 190 195 80.3 80.35 80.4 80.45 80.5

top

(2009), m

W

68% CL (by area) M

top

(2012), m

W

68% CL (by area) M & direct Higgs exclusion)

top

, m

W

LEPEWWG (2011) 68% CL (excluding M

July 2012

CDF: PRL 105, 151803 (2012) DØ: PRL 105, 151804 (2012) PRL Editors’ Suggestions

SLIDE 65

Integrated Luminosity (/pb) 10

2

10

3

10

4

10 W Mass Precision (MeV) 50 100 150 200 250 300 Run1a (e) ) µ Run1a (e+ Run1 (e) ) µ Run1 (e+ ) µ Run2 (e+ Run2 (e) ) µ Run2 (e+ Run2 (e)

CDF D0

Theoretical syst. uncert. (11 MeV)

Tevatron Single Experiment Sensitivity

Birmingham Seminar, 10/10/12 Bo Jayatilaka

Uncertainty projections

Projection assumes PDF+QED errors (11 MeV) fixed
Become limiting uncertainty for measurements with full Tevatron dataset

52

SLIDE 66

(GeV)

top

m (GeV)

W

M

= 125 GeV

H

m

155 160 165 170 175 180 185 190 195 80.3 80.35 80.4 80.45 80.5

top

, m

W

68% CL (by area) M

= 0.5 GeV

t

m

= 10 MeV,

W

M

Birmingham Seminar, 10/10/12

Bo Jayatilaka

Where could we be?

53 4

2 The LEP3 Physics case

An'interesting'measurement,'but'…'

Z pole

mW

Z pole

New Physics

Figure 3: The effect of improving the precision of the top mass measurement by a factor 10 (left), or the

precision of the Z pole and the W mass measurements by factors of 25 and 10, respectively (right), in the

(mW, mtop) plane.

From CMS Note 2012/003 P . Azzi et al. “Prospective Studies for LEP3 with the CMS Detector”

Future Tevatron mW and Tevatron+LHC mt

r... back to e+e- ?

SLIDE 67

Birmingham Seminar, 10/10/12 Bo Jayatilaka

Conclusion

CDF has performed the most precise measurement of the W boson mass
MW = 80387±19 MeV [Phys. Rev. Lett. 105, 158103]
More precise than all previous measurements combined
Improves world average uncertainty from 23 MeV to 16 MeV
New combinations (including DØ [Phys. Rev. Lett. 105, 158104])
Tevatron: MW = 80387±16 MeV (TeVEWWG, preliminary)
World: MW = 80385±15 MeV (TeVEWWG, preliminary)
Results in SM fits of MH < 152 GeV @ 95% CL
Previously MH < 161 GeV @ 95% CL
MW still is the limiting factor in MH prediction
Full Tevatron dataset (~10 fb-1) on hand
∆MW < 15 MeV per experiment achievable

54

SLIDE 68

Backup

SLIDE 69

)

e
(e) (W
10
8
6
4
2

2 4 6 8

E

S

0.998 0.999 1 1.001 1.002

1

2.2 fb

L dt
CDF II preliminary

Birmingham Seminar, 10/10/12 Bo Jayatilaka

EM calorimeter spatial uniformity

Apply tower-by-tower correction to flatten response in eta
Response after tuning flat

56

SLIDE 70

Birmingham Seminar, 10/10/12 Bo Jayatilaka

Residual alignment corrections

Some “weakly constrained modes” not corrected by cosmic alignment
Study these using difference in <E/p> between e+ and e- events
Apply correction to alignment based on this difference

57

1
0.5

0.5 1

0.01
0.005

0.005 0.01 COT cell and wire alignment With track-level corrections σ 1 ± correction a θ cot

θ cot <E/p> (positrons - electrons)

SLIDE 71

) (GeV)

(e

T

m

60 70 80 90 100

events / 0.5 GeV

5000 10000

) MeV

stat

19 ± = (80408

W

M /dof = 52 / 48

2

1

2.2 fb

L dt
CDF II preliminary

) (GeV)

µ

(

T

m

60 70 80 90 100

events / 0.5 GeV

5000 10000 15000

) MeV

stat

16 ± = (80379

W

M /dof = 58 / 48

2

1

2.2 fb

L dt
CDF II preliminary

Birmingham Seminar, 10/10/12 Bo Jayatilaka

W mass fits: mT

58 Data Simulation Data Simulation

SLIDE 72

(e) (GeV)

T

E

30 40 50

events / 0.25 GeV

5000 10000

) MeV

stat

21 ± = (80393

W

M /dof = 60 / 62

2

1

2.2 fb

L dt
CDF II preliminary

) (GeV) µ (

T

p

30 40 50

events / 0.25 GeV

5000 10000 15000

) MeV

stat

18 ± = (80348

W

M /dof = 54 / 62

2

1

2.2 fb

L dt
CDF II preliminary

Birmingham Seminar, 10/10/12 Bo Jayatilaka

W mass fits: lepton pT

59 Data Simulation Data Simulation

SLIDE 73

) (GeV)

(

e T

p

30 40 50

events / 0.25 GeV

5000 10000

) MeV

stat

25 ± = (80431

W

M /dof = 71 / 62

2

1

2.2 fb

L dt
CDF II preliminary

) (GeV)

(

µ T

p

30 40 50

events / 0.25 GeV

5000 10000

) MeV

stat

22 ± = (80406

W

M /dof = 79 / 62

2

1

2.2 fb

L dt
CDF II preliminary

Birmingham Seminar, 10/10/12 Bo Jayatilaka

W mass fits: neutrino pT

60 Data Simulation Data Simulation

SLIDE 74

) (GeV)

(

T

p

30 40 50

4
2

2 4

1

2.2 fb

L dt
CDF II preliminary
e
W

(GeV)

T

m

60 70 80 90 100

4
2

2 4

1

2.2 fb

L dt
CDF II preliminary
e
W

(l) (GeV)

T

p

30 40 50

4
2

2 4

1

2.2 fb

L dt
CDF II preliminary
e
W

Birmingham Seminar, 10/10/12 Bo Jayatilaka

Electron fit residuals

61

SLIDE 75

) (GeV)

(

T

p

30 40 50

4
2

2 4

1

2.2 fb

L dt
CDF II preliminary
µ
W

(GeV)

T

m

60 70 80 90 100

4
2

2 4

1

2.2 fb

L dt
CDF II preliminary
µ
W

(l) (GeV)

T

p

30 40 50

4
2

2 4

1

2.2 fb

L dt
CDF II preliminary
µ
W

Birmingham Seminar, 10/10/12 Bo Jayatilaka

Muon fit residuals

62

SLIDE 76

Birmingham Seminar, 10/10/12 Bo Jayatilaka

Fit window variation: mT

63

End of fit window (GeV) 84 86 88 90 92 94 96 (MeV)

W

M

50
40
30
20
10

10 20 30 40 50

T

m

e
W
1

2.2 fb

L dt
CDF II preliminary

T

m

Start of fit window (GeV) 60 62 64 66 68 70 (MeV)

W

M

50
40
30
20
10

10 20 30 40 50

T

m

e
W
1

2.2 fb

L dt
CDF II preliminary

T

m

lower upper

Start of fit window (GeV) 60 62 64 66 68 70 (MeV)

W

M

50
40
30
20
10

10 20 30 40 50

T

m

µ
W
1

2.2 fb

L dt
CDF II preliminary

T

m

End of fit window (GeV) 84 86 88 90 92 94 96 (MeV)

W

M

50
40
30
20
10

10 20 30 40 50

T

m

µ
W
1

2.2 fb

L dt
CDF II preliminary

T

m

SLIDE 77

Systematic (MeV) Electrons Muons Common Lepton Energy Scale 10 7 5 Lepton Energy Resolution 4 1 Recoil Energy Scale 5 5 5 Recoil Energy Resolution 7 7 7 u|| Efficiency Lepton Removal 3 2 2 Backgrounds 4 3 pT (W) Model (g2, g3, αs) 3 3 3 Parton Distributions 10 10 10 QED Radiation 4 4 4 Total 18 16 15

Birmingham Seminar, 10/10/12 Bo Jayatilaka

Systematics: mT

64

SLIDE 78

Systematic (MeV) Electrons Muons Common Lepton Energy Scale 10 7 5 Lepton Energy Resolution 4 1 Recoil Energy Scale 6 6 6 Recoil Energy Resolution 5 5 5 u|| efficiency 2 1 Lepton Removal Backgrounds 3 5 pT (W) model (g2, g3, αs) 9 9 9 Parton Distributions 9 9 9 QED radiation 4 4 4 Total 19 18 16

Birmingham Seminar, 10/10/12 Bo Jayatilaka

Systematics: pTl

65

SLIDE 79

Systematic (MeV) Electrons Muons Common Lepton Energy Scale 10 7 5 Lepton Energy Resolution 7 1 Recoil Energy Scale 2 2 2 Recoil Energy Resolution 11 11 11 u|| efficiency 3 2 Lepton Removal 6 4 4 Backgrounds 4 6 pT (W) model (g2, g3, αs) 4 4 4 Parton Distributions 11 11 11 QED radiation 4 4 4 Total 22 20 18

Birmingham Seminar, 10/10/12 Bo Jayatilaka

Systematics: pTv

66

SLIDE 80

Birmingham Seminar, 10/10/12 Bo Jayatilaka

Some cross-checks

67

Stat. uncertainty only. pTl fits only.

Lepton Fit Result (MeV) Electron MW+ - MW-

49±42

Electron MW(ϕ>0) - MW(ϕ<0)

58±45

Muon MW+ - MW- 71±69 Muon MW(ϕ>0) - MW(ϕ<0)

54±36

SLIDE 81

Birmingham Seminar, 10/10/12 Bo Jayatilaka

Mass fit combinations

Electron and muon mT fits combined

mW = 80390 ± 20 MeV, χ2/dof = 1.2/1 (28%)

Electron and muon pT fits combined

mW = 80366 ± 22 MeV, χ2/dof = 2.3/1 (13%)

Electron and muon MET fits combined

mW = 80416 ± 25 MeV, χ2/dof = 0.5/1 (49%)

All electron fits combined

mW = 80406 ± 25 MeV, χ2/dof = 1.4/2 (49%)

All muon fits combined

mW = 80374 ± 22 MeV, χ2/dof = 4/2 (12%)

All fits combined

mW = 80387 ± 19 MeV, χ2/dof = 6.6/5 (25%)

68

SLIDE 82

Birmingham Seminar, 10/10/12 Bo Jayatilaka

Uncertainty progress

69

SLIDE 83

168 170 172 174 176 178

mt [GeV]

80.30 80.40 80.50 80.60

MW [GeV]

MSSM MH = 114 GeV MH = 127 GeV SM

light SUSY h e a v y S U S Y MSSM SM, MSSM

Heinemeyer, Hollik, Stockinger, Weiglein, Zeune ’12

experimental errors 68% CL: LEP2/Tevatron: today

Birmingham Seminar, 10/10/12 Bo Jayatilaka

MSSM allowed region

70