Standard Model precision measurements Misure di precisione del modello standard Lesson 4: top mass measurement Stefano Lacaprara

Standard Model precision measurements Misure di precisione del modello standard

Lesson 4: top mass measurement

Stefano Lacaprara

INFN Padova

Dottorato di ricerca in fisica

Universit` a di Padova, Dipartimento di Fisica e Astronomia

Padova, 15 Marzo 2016

Outline

1 Introduction

2 Z-pole observables

3 Asymmetries

4 W mass and width

5 Top mass

6 Higgs mass and features

7 Global ElectroWeak fit

Outline

1 Introduction

2 Z-pole observables Standard Model Z lineshape

3 Asymmetries

4 W mass and width

5 Top mass

6 Higgs mass and features

7 Global ElectroWeak fit

Outline

1 Introduction

2 Z-pole observables

3 Asymmetries

Forward-Backward Asymmetries Left-Right Asymmetries Tau polarization

4 W mass and width

5 Top mass

6 Higgs mass and features

7 Global ElectroWeak fit

Outline

1 Introduction

2 Z-pole observables

3 Asymmetries

4 W mass and width Motivation At LEP II M _W at Tevatron M _W at LHC M W at Tevatron

5 Top mass

6 Higgs mass and features

Outline

1 Introduction

2 Z-pole observables

3 Asymmetries

4 W mass and width

5 Top mass Introduction General technique Lepton plus jets Dileptons Full hadronic Single top

Pole mass M top measurements Alternative M top measurements Summary of M _top

6 Higgs mass and features

Stefano Lacaprara (INFN Padova) Fit SM Padova 15/03/2016 2/52

Input to global EWK fit

(in parenthesis the order followed in these lessons)

3

− − 2 − 1 0 1 2 3

tot

O) / σ

−

indirect

(O

2

) (M

Z

α

s

2

) (M

Z (5)

α

had

∆ m

t

b

R

0 c

R

0 0,b

A

FB

0,c

A

FB

A

b

A

c

(Tevt.)

lept

Θ

eff

sin

2

)

FB lept

(Q Θ

eff

sin

2

(SLD) A

l

(LEP) A

l

0,l

A

FB

lep

R

0

0

σ

had

Γ

Z

M

Z

Γ

W

M

W

M

H

Global EW fit Indirect determination

Measurement

G fitter

SM

Mar ’18

Higgs mass (5)

I LHC

W mass and width (3)

I LEP2, Tevatron Z-pole observables (1)

I LEP1, SLD

I M _Z , Γ _Z

I σ ₀ ^had

I sin ² Θ ^lept _eff

I Asymmetries

I BR R _lep,b,c ⁰ = Γ _had /Γ _{``,b ¯ b,c ¯ c} top mass (4)

I Tevatron, LHC other:

I α _s (M _Z ² ), ∆α _had (M _Z ² )

Input to global EWK fit

(in parenthesis the order followed in these lessons)

Higgs mass (5)

I LHC

W mass and width (3)

I LEP2, Tevatron Z-pole observables (1)

I LEP1, SLD

I M _Z , Γ _Z

I σ ₀ ^had

I sin ² Θ ^lept _eff

I Asymmetries

I BR R _lep,b,c ⁰ = Γ _had /Γ _{``,b ¯ b,c ¯ c} top mass (4)

I Tevatron, LHC other:

I α _s (M _Z ² ), ∆α _had (M _Z ² )

Toq Quark introduction

Discovered at Tevatron in 1995 (> 20 years ago);

heaviest fundamental particle;

I weight as an atom of ⁷⁰ Yt, little less than Pl , or Au.

Yukawa coupling G _i =

√ 2M top

ν ∼ 1;

it decays before hadronization:

I B(t → bW ) ≈ 100%

F |V _tb | ≈ 1

I Γ _t ' G _F m _t ³ 8 √

2π |V tb | ² ∼ 1.5 GeV  Λ QCD I τ _top ∼ 10 ⁻²⁵ s < τ _QCD ∼ 10 ⁻²⁴ s;

I unique chance to study bare quark;

M _top enters (quadratically) in basically all radiative corrections

M _top and vacuum stability [1]

SM L at tree level, in the Higgs sector, has a potential V (φ) = m ² |φ| ² + λ|φ| ⁴ = 1

2 m ² H ² + 1

4 λH ⁴ + . . ., where hHi = v =

s 1

√ 2G F

= 246.2 GeV and m ² H = 2λv ²

if energy scale µ  v (eg plank scale), use a single running coupling λ(µ):

V (µ  v ) ≈ 1 4 λ(µ)H ⁴

If for some (large) value of H λ(µ) < 0, the potential become instable (or metastable)

Minimum closer to 0 is the EWK one. A second, deeper minimum can be there also.

If P-tunnel low (wrt age of universe):

metastable, otherwise unstable

Correction, and stability depends on M _H ,

M top , and α s (M Z )

Vacuum stability vs M _top and M _H

Apparently we (the universe?) are very close to the metastbility region (yellow area)

Stability for M _H [ GeV] > 129.5 + 1.4  M top [ GeV] − 173.1 0.7



− 0.5  α _s (M _Z ) − 0.1184 0.0007



Absolute stability is excluded at 98%C.L. for M _H < 126 GeV [1].

So, it is not just yet-an-other ingredient of the global SM fit.

Improving the precision of M _top (and M _H ) is crucial to understand the vacuum stability.

Th. computation rely on the assumption that the pole mass is the world average

Experiment vs Theory

What are we talking about when we talk about M _top ? [2]

M exp vs M theo

in QFT mass is a bare quantity that need to be renormalized to have physical relevance;

What we measure experimentally, from direct measurement, is the MC mass M _MC (eg via template method), namely a mass of a theory prediction

I M _MC is related to the pole of the propagator M _pole in the L but are not the same thing.

I close, but different:

M _pole = M _MC + Q ₀ [c ₁ α _S (Q ₀ ) + . . .]

F where Q ₀ is a scale used in the definition of M _MC (∼ 1 GeV in Pythia)

“The uncertainty on the translation from the MC mass definition to a theoretically well defined shortdistance mass definition at a low scale is currently estimated to be of the order of 1 GeV [3].”

on the other hand, theoretically M MC is typically evaluated in a given renormalization schema taking into

account the self-energy radiative contribution and a given cutoff;

Experiment vs Theory (II)

Theory definition of M top depends on renormalization schema several schema are used, each with its own problems

MS : “modified minimal subtraction”, introduces an arbitrary mass scale in the theory, M _MS

OS : “on-shell (pole) mass scheme” connection to the top quark’s kinematical properties physically limited for color confinement

RGI . . .

M(MS ) = M _pole (1 + 4/3α _S /π + . . .) (known up to O(α ⁴ _S ) [4]) Note that M _top (MS ) − M _top (pole) ∼ 10 GeV

MSR “low-scale short distance masses” schema interpolates smoothly between pole and MS

I M _MSR (R) −−−→ M ^R→0 pole , and M _MSR (R = M _MS ) = M _MS (R is infrared scale)

I with R ∼ 1 GeV, M MSR is as close as possible to pole

M top ^MC = M top ^MSR (R = 3 ⁺⁶ −2 ) GeV which correspond to “. . . order of 1 GeV” [5]

Side remark: σ tt depends on M pole so it can be used for direct M pole measurement

M(pole) vs M( ¯ MS )

top production at Tevatron and LHC

Production mechanism:

q ¯ q → t ¯ t

I Dominant at Tevatron (85%-15%) gg → t ¯ t

I Dominant at LHC (90%-10%)

2 4 6 8 10 12 14

[TeV]

s 10

10 2

10 3

cross section [pb]t Inclusive t

top WG LHC

topWG LHC

ATLAS+CMS Preliminary Sept 2019

* Preliminary

-1) 8.8 fb

≤ Tevatron combined 1.96 TeV (L

-1) CMS dilepton,l+jets 5.02 TeV (L = 27.4 pb

-1) 7 TeV (L = 4.6 fb µ ATLAS e

-1) 7 TeV (L = 5 fb µ CMS e

-1) 8 TeV (L = 20.2 fb µ ATLAS e

-1) 8 TeV (L = 19.7 fb µ CMS e

-1) 8 TeV (L = 5.3-20.3 fb µ LHC combined e

-1)

* 13 TeV (L = 36.1 fb µ ATLAS e

-1) 13 TeV (L = 35.9 fb µ CMS e

-1)

* 13 TeV (L = 35.9 fb µ τ+e/

CMS

-1) ATLAS l+jets* 13 TeV (L = 139 fb

-1) CMS l+jets 13 TeV (L = 2.2 fb

-1) CMS all-jets* 13 TeV (L = 2.53 fb

NNLO+NNLL (pp) ) p NNLO+NNLL (p

Czakon, Fiedler, Mitov, PRL 110 (2013) 252004 0.001

±

) = 0.118 (M

Z αs

= 172.5 GeV, NNPDF3.0, m

top

13

s

[TeV]

700 800 900

(stat)±(syst)±(lumi) σ _{t ¯ t} ( √

s = 1.96 TeV) = 7.16 ± 0.2 pb σ t ¯ t ( √

s = 7 TeV) = 173.0 ± 2 ± 8 ± 6 pb σ t ¯ t ( √

s = 8 TeV) = 241.5 ± 1.4 ^+6.3 −5.5 ± 6.4 pb σ _{t ¯ t} ( √

s = 13 TeV) = 818 ± 8 ± 27 ± 19 pb (ATLAS eµ) σ t ¯ t ( √

s = 13 TeV) = 815 ± 2 ± 25 ± 20 pb (CMS eµ) NB: σ( √

s) depends on M ^pole

Single top production also present

s and t-channels seen at TeVatron all channels measured at LHC

10 10 2

Inclusive cross-section [pb]

7 8 13

] V e [T s Preliminary

ATLAS+CMS LHC top WG

Single top-quark production September 2019

t-channel

tW

s-channel

t-channel

ATLAS

PRD90(2014)112006, EPJC77(2017)531, JHEP04(2017)086

CMS

JHEP12(2012)035, JHEP06(2014)090, arXiv:1812.10514 ATLAS+CMSJHEP05(2019)088

tW

ATLAS

PLB716(2012)142, JHEP01(2016)064, JHEP01(2018)063

CMS

PRL110(2013)022003, PRL112(2014)231802, JHEP10(2018)117 ATLAS+CMSJHEP05(2019)088

s-channel ATLAS

PLB756(2016)228

CMS

JHEP09(2016)027 ATLAS+CMSJHEP05(2019)088

58 (2014) PLB 736 NNLO scale uncertainty

091503, (2011) 83 NNLL PRD + NLO

054028 (2010) 81 054018, PRD (2010) 82 PRD

contribution removed t tW: t

uncertainty

αs

⊕

PDF

⊕

scale

74 (2015) 10, CPC191 (2010) NPPS205 NLO

top

,

F

= m

µ R

=

µ

CT10nlo, MSTW2008nlo, NNPDF2.3nlo V e G 65

F

=

µ

and V e G 60

= removal t veto for t

b

tW: p

T

scale uncertainty

uncertainty

αs

⊕

PDF

⊕

scale

stat. total

Single top vs anti-top

In general σ _t 6= σ t ¯

measured for t−channel at different √ s σ t−channel > σ tW > σ s−channel

7 8 9 10 11 12 13

[TeV]

s 1

1.2 1.4 1.6 1.8 2 2.2 2.4

t t-ch., σ / t-ch.,t σ = t R

PRD 93 (2016) 033006

CT14

JHEP 1504 (2015) 040

NNPDF 3.0

EPJC 75 (2015) 204

MMHT2014

74 (2015) 10, CPC 191 (2010) NPPS 205

NLO QCD

= mtop µF

= µR

= 172.5 GeV, mtop

PRD 90 (2014) 112006 -1 ,

ATLAS, 4.59 fb

EPJC 77 (2017) 531 -1 ,

ATLAS, 20.2 fb

JHEP 06 (2014) 090 -1 ,

CMS(*), 19.7 fb

JHEP 04 (2017) 086 -1 ,

ATLAS, 3.2 fb

arXiv:1812.10514 -1 , CMS, 35.9 fb LHC top ^WG

ATLAS+CMS Preliminary September 2019

relaxed assumptions on PDF correlations (*) Larger uncertainties are due to

stat.

total

t ¯ t event signatures

General technique

Issues:

I complex final state: jets, b-tagging, leptons, MET;

F combinatorics

I The name of the game is: jet energy scale Techniques:

I kinematical fit to M(jj ) = M _W and M _t = M t ¯ ;

I kin fit also to reduce combinatorics;

I use unconstrained W → jj decay to simultaneously fit JES ;

I residual JES for b-jets can also be exctacted from a fit from data;

M _top extractions:

I Template Method (standard);

I Matrix Element Method;

I Ideogram Method;

I Analytical Matrix Weighting Technique;

I many alternative others . . .

At Tevatron statistics is relevant, not much at LHC.

Lepton+jets channel

Semi-Leptonic decay.

Golden channel

I low background and high BR.

I one top fully reconstructed t → bW → bjj, one with missing nutrino t → bW → b`ν.

A critical element is the knowledge of Jet (and b-jet) Energy Scale use a kinematical likelihood fit for full reconstruction.

fit can be done in three ways:

I 1D fit reconstruct t → bjj: depends strongly on M top , JES, bJES.

I 2D fit reconstruct W → jj: strong dep. on JES, neglibible to M top , jJES

I 3D fit use an other variable strong dep. on bJES and weak on M _top and JES

I eg:

R _lb = p ^b _T /p ^W _T

R _lb ^1b = p ^b _t



p _t ^{jet W ,1} + p ^jet _t ^{W ,2}

 /2

R _lb ^2b = R _qb ^reco = p ^b _t ^had + p ^b _t ^lep p ^jet _t ^{W ,1} + p _t ^{jet W ,2}

3D simultaneous fit to extract M top , JES, bJES

Use Template method

Template method

Extensively used by Tevaton and LHC: similar to that used for M W

build an estimator sensitive to M _top

I eg invariant mass of daughters t → bjj, or P t ^` or whatever;

build various template distribution for different values of M _top ;

I parametrize the estimator vs M _top (mean M _top in the example below);

Perform a maximum likelihood fit to the data;

extract M top (and uncertainty);

CDF: lepton+jets: Template 2D

Consider separately 0,1,2 b-tags events, 2D fit (M top , JES) template fit on 3 distribution M _bjj ^reco , M _bjj ^{reco,2 nd choice} (takes into account combinatorics), M _jj

M _bjj ^reco M ^reco,2

nd choice

bjj M _jj

ATLAS lepton+jet: Template 3D [6]

ATLAS lepton+jet: results (8 TeV) [6]

M _top = 172.08 ± 0.39 ± 0.82 GeV = 172.08 ± 0.91 GeV

main systematics: JES (0.54 GeV), b-tagging (0.38 GeV)

CMS: Ideogram Method [7]

Build a event likelihood based on templates derived from MC (Ideograms)

I build templates for M _top , M _W , and background for different M _top (7), JES(5)

I consider separately templates for correct permutation and wrong permutation, based on MC jet-parton match;

loop over all permutations;

kinematic fit to tt-hypothesis

I use goodness-of-fit to cut and as a weight

Simultaneous fit of M top and JES

Ideogram Method Likelihood

L fit for every event (M top ^k.fit , M W ^reco ) to 2D (M top , JES ) templates from simulation.

L(M top , JES |ev ) ∼ L(ev |M top , JES ) = Y

ev

L(M top ^k.fit , M W ^reco |M top , JES ) L(M top ^k.fit , M _W ^reco |M top , JES ) = X

j ∈permutation

f _j P _j (M _top ^k.fit |M top , JES ) × P _j (M _W ^reco |M top , JES )

Complication for correct and wrong permutations, background.

Ideogram Results: semi-leptonic [7]

Type of Fit (Prior on JES) 1D L(sample|M top , JES = 1) 2D L(sample|M _top , JES ) JES free

Hybrid L(sample|M top , JES = 1) JES constrained from jet-energy uncertainties

Results:

[GeV]

m

t

172 172.2 172.4

JSF

0.994 0.995 0.996 0.997 0.998

log(L) = 1

∆ -2

log(L) = 4

∆ -2

log(L) = 9

∆ -2

(13 TeV) 35.9 fb-1 CMSPreliminary

M top ^1D = 171.93 ± 0.07(stat) ± 1.09(syst) GeV M _top ^2D = 172.40 ± 0.09(stat + JES ) ± 0.68(syst) GeV M top ^hyb = 172.25 ± 0.08( stat + JES) ± 0.62(syst) GeV syst from ME generator, FSR, color reconnection modelling

M _top M _W before and after goodness-of-fit cut

[GeV]

reco m W 0 50 100 150 200 250 300

Data/MC ^0.5

1 1.5 Permutations / 5 GeV 50 100 150 200 250 300 10

3

×

correct t t

wrong t t

unmatched t t Data

Single t W+jets Z+jets QCD multijet Diboson

(13 TeV) 35.9 fb

-1

CMS

Preliminary

[GeV]

reco m t

100 200 300 400

Data/MC ^0.5

1 1.5 Permutations / 5 GeV 20 40 60 80 100 120 140 10

3

×

correct t t

wrong t t

unmatched t t Data

Single t W+jets Z+jets QCD multijet Diboson

(13 TeV) 35.9 fb

-1

CMS

Preliminary

[GeV]

m reco 0 50 100 150 200 250 300

Data/MC ^0.5

1 1.5 Permutations / 5 GeV 20 40 60 80 100 120 140 160 10

3

×

correct t t

wrong t t

unmatched t t Data

Single t W+jets Z+jets QCD multijet Diboson

(13 TeV) 35.9 fb

-1

CMS

Preliminary

[GeV]

m fit

100 200 300 400

Data/MC ^0.5

1 1.5 Permutations / 5 GeV 10000 20000 30000 40000 50000 60000 70000 80000

_{tt correct}

wrong t t

unmatched t t Data

Single t W+jets Z+jets QCD multijet Diboson

(13 TeV) 35.9 fb

-1

CMS

Preliminary

M _top dependency on kinematic observables

test different modeling of color reconnections and generator (ME)

[GeV]

t,had

p

T

0 100 200 300 400

> [GeV]

hyb t

<m −

hyb t,cal

m

1.5

−

− 1 0.5

− 0 0.5 1 1.5

2

Data Powheg v2 P8 M2T4 MG5aMC@NLO [FxFx] P8 M2T4 MG5aMC@NLO [MLM] P8 M1 Powheg v2 H++ EE5C, no ME cor.

(13 TeV) 35.9 fb

-1

CMS 35.9 fb

^-1

(13 TeV) CMS

Preliminary

[GeV]

t

m

t

500 1000 1500

> [GeV]

hybt

<m −

hybt,cal

m

− 4 2

− 0 2 4

Data Powheg v2 P8 M2T4 MG5aMC@NLO [FxFx] P8 M2T4 MG5aMC@NLO [MLM] P8 M1 Powheg v2 H++ EE5C, no ME cor.

(13 TeV) 35.9 fb

-1

CMS 35.9 fb

^-1

(13 TeV) CMS

Preliminary

[GeV]

t t

p

T

0 50 100 150

> [GeV]

hyb t

<m −

hyb t,cal

m

0 1 2 3 4

Data Powheg v2 P8 M2T4 MG5aMC@NLO [FxFx] P8 M2T4 MG5aMC@NLO [MLM] P8 M1 Powheg v2 H++ EE5C, no ME cor.

(13 TeV) 35.9 fb

-1

CMS ^{35.9 fb}

^-1

^{(13 TeV)} CMS

Preliminary

Number of jets

4 5 6

> [GeV]

hybt

<m −

hybt,cal

m

2

− 1

− 0 1 2 3 4 5

^Data

Powheg v2 P8 M2T4 MG5aMC@NLO [FxFx] P8 M2T4 MG5aMC@NLO [MLM] P8 M1 Powheg v2 H++ EE5C, no ME cor.

(13 TeV) 35.9 fb

-1

CMS ^{35.9 fb}

^-1

^{(13 TeV)} CMS

Preliminary

[GeV]

b,had

p

T

50 100 150 200 250

> [GeV]

hyb t

<m −

hyb t,cal

m

− 2 1

− 0 1 2 3 4 5

Data Powheg v2 P8 M2T4 MG5aMC@NLO [FxFx] P8 M2T4 MG5aMC@NLO [MLM] P8 M1 Powheg v2 H++ EE5C, no ME cor.

(13 TeV) 35.9 fb

-1

CMS 35.9 fb

^-1

(13 TeV) CMS

Preliminary

b,had

|

| η

0 0.5 1 1.5 2

> [GeV]

hybt

<m −

hybt,cal

m

1.5

− 1

− 0.5

− 0 0.5 1 1.5

2

Data Powheg v2 P8 M2T4 MG5aMC@NLO [FxFx] P8 M2T4 MG5aMC@NLO [MLM] P8 M1 Powheg v2 H++ EE5C, no ME cor.

(13 TeV) 35.9 fb

-1

CMS 35.9 fb

^-1

(13 TeV) CMS

Preliminary

b

R

b

∆

2 4 6

> [GeV]

hyb t

<m −

hyb t,cal

m

0.8

−

− 0.6 0.4

−

− 0.2 0 0.2 0.4 0.6 0.8

1

^DataPowheg v2 P8 M2T4 MG5aMC@NLO [FxFx] P8 M2T4 MG5aMC@NLO [MLM] P8 M1 Powheg v2 H++ EE5C, no ME cor.

(13 TeV) 35.9 fb

-1

CMS ^{35.9 fb}

^-1

^{(13 TeV)} CMS

Preliminary

q

R

q

∆

1 2 3 4

> [GeV]

hyb t

<m −

hyb t,cal

m

− 3 2

− 1

− 0 1 2 3

4

^DataPowheg v2 P8 M2T4 MG5aMC@NLO [FxFx] P8 M2T4 MG5aMC@NLO [MLM] P8 M1 Powheg v2 H++ EE5C, no ME cor.

(13 TeV) 35.9 fb

-1

CMS ^{35.9 fb}

^-1

^{(13 TeV)}

CMS

Preliminary

Matrix Element Method

Use all information from the event integrating over the least known variables Observables: measured momentum of jets and leptons x.

Question: what is the most probable M _top given the set of observables x?

Method: at parton level, we can compute the probability of having a set of pseudo-observables y (partons 4-momenta) given M top (matrix element). But we observe x (jets and leptons), need to relate x to y (partons).

We have signal and background:

P ev (x |M top ) = f top P sgn (x |M top ) + (1 − f top )P bkg (x )

P _bkg (x ) depends on decay channel, P _sgn (x |M _top ) is the key

D0: Matrix Element Method [8]

P _sgn (x |M _top ) is the probability to have a set of kinematical variable x for a given M _top . Can be calculated event by event.

P _sgn (x |M _top ) = 1 σ(M top )

Z

d ⁿ σ(y |M _top )dp ₁ dp ₂ f (p ₁ )f (p ₂ )W (x , y )

1

σ(M top ) normalization: depends on M _top . Z

integrate over all unknown variables of initial state partons p ₁ , p ₂ and final state partons y . d ⁿ σ(y |M _top ) contains the LO matrix element of the process at parton-level (q ¯ q → t ¯ t or gg → t ¯ t);

f (p) is PDF (parton density function)

W (x , y ) is probability that parton-level y will be measured as a set of variables x To include also JES: P sgn (x |M top , JES )

I use Bayes’ theorem to get P _sgn (M _top , JES |x) for each events

I and then sum over all events Π _i (P _sgn (M _top , JES |x i )

ME in action

Transfer functions W (x, y)

Separate for b-jets and b-jets with µ inside

M _top = 174.98 ± 0.58( stat + JES) ± 0.49(syst) GeV

= 174.98 ± 0.76 GeV

main systematics:

residual JES (0.21 GeV), hadronization (0.26 GeV)

Dileptons channel [9]

very clean signal, almost no background but not possible full event reconstruction Template method on M `b

correct match (`b from same top) as well as wrong match (25%)

[GeV]

reco mlb

50 100 150

Normalised events / 5 GeV

0.05 0.1

mtop 167.5 GeV 172.5 GeV 177.5 GeV

ATLAS

Simulation

[GeV]

reco

m

lb

40 60 80 100 120 140 160

Ratio

0.6 0.81 1.2 1.4

[GeV]

reco

m

lb

40 60 80 100 120 140 160

Events / 2 GeV

0 100 200 300 400

500 Data

1% background Best fit Uncertainty

ATLAS

=8 TeV, 20.2 fb

-1

s

M _top = 172.99 ± 0.41 ± 0.74 GeV = 172.99 ± 0.84 GeV syst uncert from b-JES

Dileptons: neutrinos reconstruction

Analytical Matrix Weighting Technique (CMS) [10] [CDF did something similar]

Assume pure t ¯ t signal;

kin-fit underconstrained

I 2ν × 3 = 6 variables

I p _x = 0 = p _y , M(`¯ ν) = M(¯ `ν) = M _W , M _t = M t ¯ : 5 constraints scan over possible M _top ;

for each M _top we have 0,2, or 4 solutions (intersection of two ellipses), plus permutation (2b, 2`);

for each solution build a weight taking into account the LO matrix element

take M top corresponding to highest X

w : M AMWT

likelihood fit to extract mass;

M _top = 172.8 ± 0.2 ± 1.2 GeV (syst dominated by JES)

Full hadronic

Large background;

not trivial to trigger (no lepton, purely jet-like, high threshold);

independent data sample;

no MET, no dependence on MET modelling;

full reconstruction but large combinatorics;

color reconnections;

JES, bJES,. . .

I Ideogram 1D (M _top ) and 2D (M _top + JSF) or Hybrid (JSF gaussian constraint)

F different weight for correct/uncorrect combinations

I Template fit from R _3/2 = M(bjj )/M(jj )

CMS Ideogram method 2D at 8 TeV

CMS Ideogram method 2D at 13 TeV [11]

trigger:

I HT > 450 GeV (scalar sum of hadronic energy in event)

I N ≥ 6 jets (p T > 40 GeV)

I N ≥ 1 jets b-tagged selection:

I 6 Jets

I 2 b-tagged

I p _T (jets) > 40 GeV

I ∆R(b ¯ b) > 2.0

kin-fit: M _W + = M _W − = M W (PDG ) and M t = M t ¯

large combinatorics! Select best χ ² of kin-fit

[GeV]

fit

m

t

100 200 300 400

Data/MC 0.5 1 1.5

Events / 5 GeV

200 400 600 800 1000 1200 1400 1600 1800

_{tt correct}

wrong t t

Multijet Data

(13 TeV) 35.9 fb

-1

CMS

[GeV]

reco

m

W

70 80 90 100 110 120

Data/MC 0.5 1 1.5

Events / 1 GeV

200 400 600 800 1000

correct t t

wrong t t

Multijet Data

(13 TeV) 35.9 fb

-1

CMS

Ideogram fit (1D, 2D, hybrid)

M _top = 172.34±0.20(stat +JSF )±0.76(syst) GeV

syst from Color Reconnection, bJet correction

Full hadronic ATLAS: R _{3 /2} [12]

All hadronic final states.

Use the R _3/2 distribution as the estimator for M _top instead of m _jjj

I More protected from JES variation: R _3/2 = m _bjj

m _jj ∝ JES · bJES JES

Entries / 3 GeV

200 400 600 800 1000 ATLAS

Ldt = 20.2 fb

-1

∫

= 8 TeV s Data

MC (Correct) t t

MC (Incorrect) t t

MC (Non-Matched) t t

QCD Multi-jet (Data-Driven) Syst. Uncertainty

⊕ Stat.

[GeV]

140 160 180 200 220 240 260 280 300 m

Data / Prediction

0.5 1 1.5

Entries / 0.04

200 400 600 800 1000

ATLAS Ldt = 20.2 fb

-1

∫

= 8 TeV s Data

MC (Correct) t t

MC (Incorrect) t t

MC (Non-Matched) t t

QCD Multi-jet (Data-Driven) Syst. Uncertainty

⊕ Stat.

/m = m 1.6 1.8 2 2.2 2.4 2.6 2.8 3 R 3.2 3.4

Data / Prediction

0.5

1

1.5

M _top from single top production

Method:

decay channel: t → bW → µν.

production: mostly t-channel

Requires: 1µ ⁺ (σ t > σ t ¯ ), MET, 1 b-jet (plus other forward jet |η _j | > 2.5 - associated prod- ).

Template method on M _µνb or M _`b

(GeV)

gen

m

t

166 168 170 172 174 176 178 180

(GeV) µ

160 162 164 166 168 170 172 174

Simulation (8 TeV)

CMS

Results:

CMS [13]

M top = 172.95 ± 0.77 ^+0.97 _−0.93 GeV = 172.95 ± 1.24 GeV syst: JES (0.68 GeV), bkgn (0.39 GeV), fit (0.39 GeV)

ATLAS [14] M top = 172.2 ± 0.7 ± 2.0 GeV

D0: Pole mass M _top measurements

Indirect pole mass measurement can be extracted from a x-section measurement, total or differential.

Compare σ t ¯ t with NNLO+NNLL prediction [15] a function of MC M top .

I in semi-leptonic and di-leptonic channels

the fit to extract the σ is based on a signal which depends on M _top ^MC

I so we measure σ for different M _top ^MC .

Or from differential σ _t¯t (p _T )

Pole mass M _top measurements at LHC

ATLAS [16, 17, 18], CMS [19, 20, 21]

Inclusive σ t ¯ t 7+8+13 TeV σ _{t ¯ t+jet} 7+8 TeV

Differential vs p _T ^` , p _T ^`` , m _eµ , . . . for t ¯ t → eµ + X events 8+13 TeV

155 160 165 170 175 180 185 190

[GeV]

m

top

ATLAS+CMS Preliminary m

top

from cross-section measurements top WG

LHC Sep 2019

from top quark decay mtop

ATLAS, 7+8 TeV comb. [11]

CMS, 7+8 TeV comb. [10]

total stat m

top±

tot (stat

^±

^syst

^±

^theo)

Ref.

) n-differential, NLO t

σ (t

+1j) differential, NLO t

σ (t

) inclusive, NNLO+NNLL t

σ (t

ATLAS, 7+8 TeV

-2.6 [1]

172.9

+2.5

CMS, 7+8 TeV

-1.8+1.7 [2]

173.8

CMS, 13 TeV

-1.5+1.2

)

[3]

1.5

± (0.1

-2.1

169.9

+1.9

ATLAS, 13 TeV

-2.1 [4]

173.1

+2.0

ATLAS, 7 TeV

-0.5+1.0

)

[5]

1.4

± (1.5

-2.1

173.7

+2.3

CMS, 8 TeV 169.9

-3.7+4.5

(1.1

-3.1+2.5

-1.6+3.6

)

[6]

ATLAS, 8 TeV

-0.3+0.7

)

[7]

0.9

± (0.4

-1.0

171.1

+1.2

ATLAS, n=1, 8 TeV 173.2 ± 1.6 (0.9 ± 0.8 ± 1.2)

[8]

CMS, n=3, 13 TeV 170.9 ± 0.8

[9]

[1] EPJC 74 (2014) 3109 [2] JHEP 08 (2016) 029 [3] EPJC 79 (2019) 368 [4] ATLAS-CONF-2019-041

[5] JHEP 10 (2015) 121 [6] CMS-PAS-TOP-13-006 [7] arXiv:1905.02302 (2019) [8] EPJC 77 (2017) 804

[9] arXiv:1904.05237 (2019) [10] PRD 93 (2016) 072004 [11] EPJC 79 (2019) 290

Summary (march 2018, last meas.

from CMS [21] not included)

150 160 170 180

[GeV]

m t 0

2 4 6 8

-4.70

GeV

+5.20

167.50 ), 1.96 TeV

t (t σ D0 PLB 703 (2011) 422 MSTW08 approx. NNLO

-3.40

GeV

+3.30

169.50 ), 1.96 TeV

t (t σ D0

D0 Note 6453-CONF (2015) MSTW08 NNLO

-3.20

GeV

+3.40

172.80 ), 1.96 TeV

t σ (t D0 PRD 94, 092004 (2016) MSTW08 NNLO

-2.60

GeV

+2.50

172.90 ), 7+8 TeV

t σ (t ATLAS EPJC 74 (2014) 3109

-2.11

GeV

+2.28

173.70 +j shape, 7 TeV

t ATLAS t JHEP 10 (2015) 121

-1.80

GeV

+1.70

173.80 ), 7+8 TeV

t (t σ CMS JHEP 08 (2016) 029 NNPDF3.0

-2.70

GeV

+2.70

170.60 ) 13 TeV

t (t σ CMS JHEP 09 (2017) 051 CT14

-3.66

GeV

+4.52

169.90 +j shape, 8 TeV

t CMS t TOP-13-006 (2016)

-0.76 GeV +0.76 173.34

World combination

ATLAS, CDF, CMS, D0 arXiv:1403.4427, standard measurements

March 2018 Top-quark pole mass measurements

M top ^pole = 173.34 ± 0.76 GeV

Alternative methods

Incomplete list of M top measurements technique Extract M _top in well defined renormalization schema, eg via template method

Observables/final states sensitive to different systematic uncertainties:

in particular, less sensitive to JES and bJES.

I dilepton channel

F End Point [22];

F M _{T 2} /MAOS [23];

F M _lb [24];

F bJet Energy (E _b ) [25];

F dilepton p _T [26]

I lepton+jets channel

F boosted top: e/µ+jets [27];

F Bi-Event Subtraction Technique (BEST) [28]

I dilepton and lepton+jets channels

F B-hadron lifetime [29];

F lepton + Secondary Vertex Mass [30];

CMS: kinematic End Point [22]

Using di-lepton decays, usual selections;

possibly sensitive to DM candidates (WIMPS) (not really) basic idea similar to M _T = in W → `ν decay:

I M _T ² = m _ν ² + m ² <sub>`</sub> + 2(E <sub>T</sub> <sup>ν</sup> E <sub>T</sub> <sup>`</sup> − ~p ^ν T p ~ ^` _T )

I where ~ p ^` _T = ~ p ^miss _T

I M _T ≤ M W always. For each event not so important, but for an ensamble of events the endpoint is sensitive to M _W

based on M _{T 2} (p _T ^` , p _T ^b , p ^miss _T ) using “min-max” strategy for two identical decay chain

I It is always true max(M _T ^a , M _T ^b ) ≤ M top .

I but ~ p _ν ^a,b _T cannot be know separately, only the sum ~ p _ν ^a _T + ~ p _ν ^b _T

I consider all possible partition such that ~ p _ν ^a _T + ~ p _ν ^b _T = ~ p _T ^miss and take the minimum.

I sensitive to minimum parent mass M consistent with observed event kinematics

M _{T 2} = min

~

p _ν ^a _T + ~ p _ν ^b _T =~ p _T ^miss



max {M T ^a , M _T ^b } 

I M _{T 2} endpoint is related to the unseen parent mass (ν or WIMPS)

Observables and results

Three observables can be used to extract three masses M _top , M _W , and M ν,WIMP

µ ``

I considering the W ^± decays only, and the ν as lost child particles;

I µ ^max _`` ∝ M W

µ _bb

I considering the t ¯ t decays only, and considering W ^± as lost child particles;

I µ ^max _bb ∝ M top I sensitive to JES M bl

I third variables

I M _bl = q

(p _b + p _` ) ²

I combinatorial problem: which b goes with wich `?

I M _bl ^max ∼ q

M _top ² − M W ² ∼ 153 GeV

Results: m ² _ν = −556 ± 473 ± 622 GeV,

M _top = 173.9 ± 0.9(stat) ^+1.7 −2.1 (syst) GeV [22]

MAOS M <sup>b`ν</sup> b`ν inv mass

the neutrino p T is obtained, event per event, as the results of minimization of M _{T 2} ^``

I M _{T 2} ^`` sensitive to M _W

I equivalent to assume null neutrino masses

applies M _W constraint to get p ν ^z

8-fold ambiguities

peaked around M _top

not very sensitive to JES

(M T 2 ^`` )

CMS: M _lb , M _{T 2} and MAOS M _{bl ν} observables [23]

M b` , M T 2 <sup>bb</sup> , and MAOS M <sup>b`ν</sup> dependence on M top and sensitivity

[GeV]

M

bl

40 60 80 100 120 140 160 180

Arbitrary units

0 2 4 6 8 10 12 14 16 18 20 22

−3

×

10

= 166.5 GeV MC Mt

= 172.5 GeV MC Mt

= 178.5 GeV MC Mt Local shape sensitivity

(8 TeV) CMS

Simulation

[GeV]

bb

M

T2

120 140 160 180 200

Arbitrary units

0 5 10 15 20 25 30 35

−3

×

10

= 166.5 GeV MC Mt

= 172.5 GeV MC Mt

= 178.5 GeV MC Mt Local shape sensitivity

(8 TeV) CMS

Simulation

[GeV]

ν

M

bl

100 150 200 250 300

Arbitrary units

0 2 4 6 8 10 12 14

−3

×

10

= 166.5 GeV MC Mt

= 172.5 GeV MC Mt

= 178.5 GeV MC Mt Local shape sensitivity

(8 TeV) CMS

Simulation

Sensitivity to Jet Scale Factor

[GeV]

M

bl

40 60 80 100120 140160 180

Arbitrary units

0 2 4 6 8 10 12 14 16

−3

×10

JSF = 0.97 JSF = 1.00 JSF = 1.03 (8 TeV) CMS

Simulation

[GeV]

bb

M

T2 110 120 130 140 150 160 170 180 190 200

Arbitrary units

0 5 10 15 20 25

−3

×10

JSF = 0.97 JSF = 1.00 JSF = 1.03 (8 TeV) CMS

Simulation

fit: 1D (only M _top ), 2D (M _top and JES) hybrid 1/2D linearly combined

[GeV]

M

t

170 170.5 171 171.5 172 172.5 173

JSF

0.99 0.995 1 1.005 1.01 1.015 1.02 1.025 1.03 1.035 1.04

0 20 40 60 80 100 120 140 160 (8 TeV) 19.7 fb

-1

CMS Hybrid fit

= -0.40 ρ

[GeV]

M

t

160 165 170 175 180 185

1D fit

2D fit

Hybrid fit

MAOS fit

CMS 2012, dilepton PRD 93, 2016, 072004

CMS combination PRD 93, 2016, 072004

GeV 0.95

− 0.91 0.17 +

± 172.39

GeV 1.25

− 1.31 0.46 +

± 171.56

GeV 0.93

− 0.89 0.18 +

± 172.22

GeV 1.02

− 1.27 0.19 +

± 171.54

1.22 GeV

± 0.19

± 172.82

0.47 GeV

± 0.13

± 172.44

syst)

± stat

± (value

(8 TeV) 19.7 fb-1

CMS

M _top from B-jet energy spectrum [25]

Di lepton channels: e + µ top produces W on-shell, so m _t = E _b ^rest +

q

m ² _W − m ² _b + E _b ^{rest 2}

measure of b-quark energy in the top rest frame E _b ^rest and get M _top

possible if assume top to be unpolarized M _top = 172.29 ± 1.17(stat) ± 2.66(syst) GeV

log(E)

3.5 4 4.5 5 5.5 6 6.5 7

/dlog(E)

bjets

1/E dN

5 10 15 20 25

Data VV

W+Jets t t V Single top DY

t

t QCD

CMS Preliminary

(8 TeV) 19.7 fb -1

log(E)

3.5 4 4.5 5 5.5 6 6.5 7

MC Data

0.8 1

1.2

M _top from leptonic observables [26]

Di lepton channels: e + µ

using only leptonic observables not sensitive to JES/bJES systematics

Using p _T (` <sup>+</sup> ` ⁻ ) as observable

compute first and second moment of p _T (` <sup>+</sup> ` ⁻ ) distribution O ^(1,2) , also from shape analysis

O ^(1,2) sensitive to M _top (and production mechanism: t ¯ t, tW )

M _top = 171.7 ± 1.1( stat) ± 0.5(exp)

± 3.0( th) ^+0.8 −0.0 ( p T ( top)) GeV syst dominated by theo uncertainties on modeling

Mass [GeV]

166168170172 174176178

(ll) [GeV]

T

p

1

O

62 63 64 65 66 67

68 tt+tW combination

0.008

± 1 slope=0.146

± offset= 39 tt

±0.01 2 slope=0.09

± tW offset= 50 Simulation Preliminary CMS

Mass [GeV]

166168 170172174176 178

]

2

(ll) [GeV

T

p

2

O

4700 4800 4900 5000 5100 5200

5300 tt+tW combination

±1 slope=21 2)x102

± offset=(13 t t

±1 slope=13 2)x102

± tW offset=(29 Simulation Preliminary CMS

CMS: Boosted top e/µ+jets [27]

Selection is: 1 e/µ, ≥ 2 narrow jets, ≥ 2 fat jets, MET

top boost is such that the W → jj decay is not resolved into two different jet, but in a “fat” one.

Sensitive quantity is the fat jet mass differential σ

[GeV]

Leading-jet m jet

150 200 250 300 350

-1

GeV

jet

dm σ d σ 1

0 0.005 0.01 0.015

Data 178.5 GeV

t

= m

172.5 GeV

t

= m

166.5 GeV

t

= m CMS

(8 TeV)

19.7 fb -1 uncertaities

[GeV]

Leading-jet m jet

150 200 250 300 350

Relative uncertainty [%]

0 20 40 60 80 100 120

140 Stat

⊕

model

Statistical scales

µF

,

µR

Parton shower

Choice of m

t

PDF

(8 TeV) 19.7 fb

-1

CMS

M top = 170.8 ± 6.0(stat) ± 2.8(syst) ± 4.6(model ) ± 4.0(th) GeV = 170.8 ± 9.0 GeV

Not yet competitive: need more data, better modelling, and higher order calculations

M _top Bi-Event Subtraction Technique (BEST) assisted [28]

Measurement is based on semileptonic events, using M _jjb and R _3/2 = M _jjb /M _jj observables

BEST is a data-driven background-estimation technique, originally developed for squark searchs in SUSY

Basic idea is to mix jets from different events to estimate combinatorial background.

Template fit on M jjb and R 3/2 to extract M top

100 200 300 400 500 600

Combinations / 10 GeV

2000 4000 6000

data Signal BEST

(8 TeV) 19.7 fb-1

CMS Preliminary

(GeV) m

jjb

100 200 300 400 500 600

data/Fit

0.8 0.9 1 1.1

1.2 mjjb (GeV)

100 120 140 160 180 200 220 240

Combinations / 10 GeV

0 500 1000 1500 2000 2500

data - BEST Signal

(8 TeV) 19.7 fb-1

CMS Preliminary

(GeV) m

jjb

100 120 140 160 180 200 220 240

Fitdata - BEST ^-2 0 2 4

1 1.5 2 2.5 3 3.5 4 4.5

Combinations / 0.1

2000 4000 6000 8000 10000 12000

data Signal BEST

(8 TeV) -1 19.7 fb

CMS Preliminary

/m

jj

m

jjb

1 1.5 2 2.5 3 3.5 4 4.5

data/Fit

0.8 0.9 1 1.1 1.2

/mjj mjjb

1.4 1.6 1.8 2 2.2 2.4 2.6 2.8 3

Combinations / 0.1

0 500 1000 1500 2000

data - BEST Signal

(8 TeV) -1 19.7 fb

CMS Preliminary

/m

jj

m

jjb

1.4 1.6 1.8 2 2.2 2.4 2.6 2.8 3

Fitdata - BEST ^-2 0 2 4

M top = 171.61 ± 0.57( stat) ± 0.90(syst) GeV

CMS: b-hadron lifetime [29]

t → Wb: in the top rest frame, the b momentum is linearly dependent on top mass p ≈ 0.4M _top the (transverse) decay lenght of the b depends on b boost γ b ∼ 0.4(M top /M b )

L xy = γ b β b cτ b ∼ 0.4M top /M b β b cτ b

given cτ _b ∼ 500µm, M top /M _b ∼ 34.5:

∆L _xy /M _top ∼ 50µm/GeV

Template method based on L _xy (median)

I Statitstics is high

I no jet-related measurement

I main syst: top p T modelling, b-fragmentation and hadronization still a long way to go. . .

[GeV]

m

top

162 164 166 168 170 172 174 176 178 180 182

[cm]xyL

0.62 0.64 0.66 0.68 0.7 0.72 0.74 0.76

-channel µ e

+jets-channel µ e+jets-channel

=8 TeV s CMS Simulation,

M _top = 173.5 ± 1.5(stat) ± 1.3(syst) ± 2.6(top p _T ) GeV

CMS: Lepton + secondary vertex [30]

Semi or full-leptonic t → W (→ `ν)b decay;

I different categories SL e + jets, µ + jets and FL ee, eµ, µµ b decay produces a secondary vertex displaced wrt primary and reconstructed;

M _top sensitive variable is the invariant mass M _{sv `} :

I ` from W

I the secondary vertex tracks

it is similar to the ` + J/ψ method (next slide) much larger statistics (inclusive vs esclusive b decay) does not relies on jet reconstruction so no JES scale issue

M _top = 173.68 ± 0.20 ^+1.58 −0.97 GeV syst dominated: b-quark fragmentation, top p T modelling, σ(t ¯ t + HF ), ME, ` energy scale, SV modelling . . .

Combinations / 3.9 GeV

0 2000 4000 6000 8000 10000 12000 14000 16000

18000 Data

= 166.5 GeV m

t

= 172.5 GeV m

t

= 178.5 GeV m

t

(8 TeV) 19.7 fb

-1

CMS

[GeV]

m

svl

20 40 60 80 100 120 140 160 180 200 0.8

1 1.2

Ratio wrt. 172.5 GeV

Different final states and num tracks categories considered:

170 171 172 173 174 175 176 177 178

3 trk. 4 trk. 5 trk.

(8 TeV) 19.6 fb-1

[GeV]tm

170 171 172 173 174 175 176 177 178

Combination eµ ee µµ e+jets µ+jets

CMS

CMS: Lepton +J/ψ [31]

Decay channel is:

t → W (→ `ν)b → (J/ψ (→ µµ) + X )

I B(W → `ν) ∼ N ` · 10%

I B(B → J/ψX ) ∼ 0.1%

I B(J/ψ → µµ) ∼ 6%

¯ ¯t b W

⁻

j/`

⁻

j/¯ ν

t W

⁺

b

b hadron ν

µ

⁺

(e

⁺

)

J/ψ µ

⁺

µ

⁻

1

double and single top production Limited statistics (666 ev in 19.7 fb ⁻¹ ) Template method based on M(J/ψ + `)

I Purely leptonic quantities

I no jet related ones! (JES, bJES, etc)

(GeV) + l ψ m J/

0 50 100 150 200 250

Events / ( 10 GeV )

0 20 40 60 80

100 m

_t

= (173.5 ± 3.0) GeV

CMS 19.7 fb

^-1

(8 TeV)

(GeV) m t

170 180

) max log(L/L −

0 1 2 3 4

Data Fit result Statistical uncertainty gamma component Gaussian component 3.0) GeV

± = (173.5 m

t

M top = 173.5 ± 3.0 ± 0.9 GeV

Limited statitics, top p _T modelling and QCD

scales

CMS: alternative M _top measurement summary

Alternative

160 170 180 190

[GeV]

m t 0

5 10

2.91 GeV

± 1.50

± 173.50 b hadron lifetime

CMS-PAS-TOP-12-030 (2013)

-2.10 GeV +1.70 0.90

± 173.90 Kinematic endpoints

EPJC 73 (2013) 2494

2.66 GeV

± 1.17

± 172.29 b-jet energy peak

CMS-PAS-TOP-15-002 (2015)

0.90 GeV

± 3.00

± 173.50 Ψ

Lepton+J/

JHEP 12 (2016) 123

-0.97 GeV +1.58 0.20

± 173.68 Lepton+SecVtx

PRD 93 (2016) 092006

-3.09 GeV +2.68 1.10

± 171.70 Dilepton kinematics

CMS-PAS-TOP-16-002 (2016)

-0.93 GeV +0.97 0.77

± 172.60 Single top enriched

EPJC 77 (2017) 354

-0.93 GeV +0.89 0.18

± 172.22 /MAOS observables

MT2 PRD 96 (2017) 032002

0.90 GeV

± 0.57

± 172.61 BEST backgrounds

CMS-PAS-TOP-14-011 (2015)

-1.29 GeV +1.24 0.32

± 172.30 Dilepton Mlb

CMS-PAS-TOP-14-014 (2014)

0.47 GeV

± 0.13

± 172.44 CMS Run 1 legacy

PRD 93 (2016) 072004 standard measurements

May 2019

syst.)

± stat.

± (value

CMS Preliminary

Standard

5 10

15

175.50 ± 4.60 ± 4.60 GeV

Dilepton JHEP 07 (2011) 049, 36 pb-1

1.43 GeV

± 0.43

± 172.50 Dilepton

EPJC 72 (2012) 2202, 5.0 fb-1

1.21 GeV

± 0.69

± 173.49 All-jets

EPJC 74 (2014) 2758, 3.5 fb-1

0.98 GeV

± 0.43

± 173.49 Lepton+jets

JHEP 12 (2012) 105, 5.0 fb-1

1.22 GeV

± 0.19

± 172.82 Dilepton

PRD 93 (2016) 072004, 19.7 fb-1

0.59 GeV

± 0.25

± 172.32 All-jets

PRD 93 (2016) 072004, 18.2 fb-1

0.48 GeV

± 0.16

± 172.35 Lepton+jets

PRD 93 (2016) 072004, 19.7 fb-1

0.47 GeV

± 0.13

± 172.44 CMS Run 1 legacy

PRD 93 (2016) 072004

-0.72 GeV +0.66 0.24

± 172.33 Dilepton

EPJC 79 (2019) 368, 35.9 fb-1

0.62 GeV

± 0.08

± 172.25 Lepton+jets

EPJC 78 (2018) 891, 35.9 fb-1

0.70 GeV

± 0.20

± 172.34 All-jets

EPJC 79 (2019) 313, 35.9 fb-1

0.61 GeV

± 0.07

± 172.26 Lepton+jets, all-jets

EPJC 79 (2019) 313, 35.9 fb-1

2.44 GeV

± 0.41

± 172.56 > 400 GeV

Single jet, pT _-1 TOP-19-005 (2019), 35.9 fb

0.54 GeV

± 0.35

± 174.30 Tevatron combination

arXiv:1608.01881 (2016)

0.71 GeV

± 0.27

± 173.34 World combination

September 2019

CMS

M pole

160 180

[GeV]

pole m t

0

2 4

6 tt+j shape, 8 TeV 169.90 +4.52-3.66 ^GeV TOP-13-006 (2016), 19.7 fb-1

NLO

-1.80 GeV +1.70 173.80 ), 7+8 TeV

t σ(t

JHEP 08 (2016) 029, 5.0 + 19.7 fb-1 NNLO+NNLL, NNPDF3.0

-2.30 GeV +2.10 173.20 ), 13 TeV

t σ(t

EPJC 79 (2019) 368, 35.9 fb-1 NNLO+NNLL, NNPDF3.1

-0.72 GeV +0.72 170.83 ), 13 TeV

t σ(t triple-differential arXiv:1904.05237 (2019), 35.9 fb-1 NLO, HERAPDF2.0

-0.80 GeV +0.80 170.50 ), 13 TeV

t σ(t triple-differential arXiv:1904.05237 (2019), 35.9 fb-1

, PDF) αS pole, NLO, 3D fit (mt

-0.49 GeV +0.49 172.44 CMS Run 1 legacy

PRD 93 (2016) 072004 from standard measurements mt

June 2019

tot.)

± (value

CMS Preliminary

Alternative techniques are competitive with standard ones multi-differntial pole measurement also

Different systematics, important

Summary of M _top measurement

Tevatron

174.30 ± 0.35 ± 0.54 GeV

ATLAS Run I+II combination (2018)

[GeV]

m

top

165 170 175 180 185

1 19

0.64

± 174.34

(arXiv:1407.2682) Tevatron Comb. Jul. 2014

0.76

± 173.34

(arXiv:1403.4427) World Comb. Mar. 2014

0.48

± 172.69

(arXiv:1810.01772) ATLAS Comb. October 2018

-1 =20.2 fb int L Eur. Phys. J. C 77 (2017) 804 ) dilepton (8 dist.) t σ(t

Differential 173.2 ± 1.6

-1 =4.6 fb int L JHEP 10 (2015) 121 +1-jet) t σ(t

Differential 2.1

± 2.3 173.7

-1 =4.6-20.3 fb int L Eur. Phys. J. C74 (2014) 3109 ) dilepton t

σ(t 2.6

± 2.5 172.9 = 20.2 fb-1

Lint arXiv:1810.01772 l+jets

→ 172.1 ± 0.9 ( 0.4 ± 0.8 )

= 20.2 fb-1 Lint JHEP 09 (2017) 118 all jets

→ 173.7 ± 1.2 ( 0.6 ± 1.0 )

= 20.2 fb-1 Lint Phys. Lett. B761 (2016) 350 dilepton

→ 173.0 ± 0.8 ( 0.4 ± 0.7 )

= 4.7 fb-1 Lint Eur. Phys. J. C75 (2015) 330 dilepton

→ 173.8 ± 1.4 ( 0.5 ± 1.3 )

= 4.7 fb-1 Lint Eur. Phys. J. C75 (2015) 330 l+jets

→ 172.3 ± 1.3 ( 0.2 ± 0.2 ± 0.7 ± 1.0 )

=20.3 fb-1 Lint ATLAS-CONF-2014-055

single top* 172.2 ± 2.1 ( 0.7 ± 2.0 ) = 4.6 fb-1

Lint Eur. Phys. J. C75 (2015) 158 all jets

→ 175.1 ± 1.8 ( 1.4 ± 1.2 )

- 20.3 fb

-1

= 4.6 fb

-1

summary - November 2018, L

int

m

top

syst.)

± bJSF

± JSF

± tot. (stat.

± mtop

σ

± 1 World Comb.

stat. uncertainty bJSF uncertainty

⊕ JSF

⊕ stat.

total uncertainty Input to ATLAS comb.

→ Preliminary,

*

ATLAS Preliminary

172.69 ± 0.48 GeV

CMS

165 170 175 180

[GeV]

m

t 0

2 4 6 8

0.47 GeV

± 0.13

± 172.44 CMS Run 1 legacy

PRD 93 (2016) 072004

0.70 GeV

± 0.38

± 172.62 2015, muon+jets

TOP-16-022 (2017), 2.2 fb-1

0.62 GeV 0.08 ± 172.25 ± Lepton+jets

EPJC 78 (2018) 891, 35.9 fb-1

GeV -0.72 +0.66 0.24 172.33 ± Dilepton

EPJC 79 (2019) 368, 35.9 fb-1

0.70 GeV

± 0.20

± 172.34 All-jets

EPJC 79 (2019) 313, 35.9 fb-1

0.61 GeV

± 0.07

± 172.26 Lepton+jets, all-jets

EPJC 79 (2019) 313, 35.9 fb-1

2.44 GeV

± 0.41

± 172.56 > 400 GeV

Single jet, pT TOP-19-005 (2019), 35.9 fb-1

0.54 GeV

± 0.35

± 174.30 Tevatron combination

arXiv:1608.01881 (2016)

0.71 GeV

± 0.27

± 173.34 World combination

ATLAS, CDF, CMS, D0 arXiv:1403.4427 (2014)

September 2019

syst.)

± stat.

± (value CMS

Run I combination (2016) 172.44 ± 0.13 ± 0.47 GeV Weighted avg (uncorrelated):

172.38 ± 0.23 GeV

Summary of M _top measurement

[GeV]

m top

165 170 175 180 185

1 17

LHC September 2013 173.29 ± 0.95 (0.23 ± 0.26 ± 0.88)

Tevatron March 2013 (Run I+II) 173.20 ± 0.87 (0.51 ± 0.36 ± 0.61)

prob.=93%

χ2² / ndf =4.3/10

World comb. 2014

χ

173.34 ± 0.76 (0.27 ± 0.24 ± 0.67)

= 3.5 fb-1 Lint

CMS 2011, all jets 173.49 ± 1.41 (0.69 ± 1.23)

= 4.9 fb-1 Lint

CMS 2011, di-lepton

1.46)

± (0.43 1.52

± 172.50

= 4.9 fb-1 Lint

CMS 2011, l+jets

0.97)

± 0.33

± (0.27 1.06

± 173.49

= 4.7 fb-1 Lint

ATLAS 2011, di-lepton

1.50)

± (0.64 1.63

± 173.09

= 4.7 fb-1 Lint

ATLAS 2011, l+jets 172.31 ± 1.55 (0.23 ± 0.72 ± 1.35)

= 5.3 fb-1 Lint

D0 RunII, di-lepton

1.38)

± 0.55

± (2.36 2.79

± 174.00

= 3.6 fb-1 Lint

D0 RunII, l+jets

1.16)

± 0.47

± (0.83 1.50

± 174.94

= 8.7 fb-1 Lint

+jets

miss

CDF RunII, E

T

0.86)

± 1.05

± (1.26 1.85

± 173.93

= 5.8 fb-1 Lint

CDF RunII, all jets 172.47 ± 2.01 (1.43 ± 0.95 ± 1.04)

= 5.6 fb-1 Lint

CDF RunII, di-lepton

3.13)

± (1.95 3.69

± 170.28

= 8.7 fb-1 Lint

CDF RunII, l+jets

0.86)

± 0.49

± (0.52 1.12

± 172.85

- 8.7 fb

-1

= 3.5 fb

-1

combination - March 2014, L

int

Tevatron+LHC m

top

ATLAS + CDF + CMS + D0 Preliminary

) syst.

iJES stat.

total ( Previous Comb.

World combination (2014): M _top = 173.34 ± 0.27 ± 0.71 GeV

Summary of M _top measurement

165 170 175 180 185

[GeV]

m top

ATLAS+CMS Preliminary m

top

summary, s = 7-13 TeV top WG

LHC

May 2019

World comb. (Mar 2014) [2]

stat total uncertainty

total stat syst)

± total (stat top±

m s Ref.

topWG

LHC comb. (Sep 2013)

LHC 173.29 ± 0.95 (0.35 ± 0.88) 7 TeV [1]

World comb. (Mar 2014)

173.34 ± 0.76 (0.36 ± 0.67) 1.96-7 TeV [2]

ATLAS, l+jets

172.33 ± 1.27 (0.75 ± 1.02) 7 TeV [3]

ATLAS, dilepton

173.79 ± 1.41 (0.54 ± 1.30) 7 TeV [3]

ATLAS, all jets

175.1 ± 1.8 (1.4 ± 1.2) 7 TeV [4]

ATLAS, single top

172.2 ± 2.1 (0.7 ± 2.0) 8 TeV [5]

ATLAS, dilepton

172.99 ± 0.85 (0.41 ± 0.74) 8 TeV [6]

ATLAS, all jets

173.72 ± 1.15 (0.55 ± 1.01) 8 TeV [7]

ATLAS, l+jets

172.08 ± 0.91 (0.39 ± 0.82) 8 TeV [8]

ATLAS comb. (Oct 2018)

172.69 ± 0.48 (0.25 ± 0.41) 7+8 TeV [8]

CMS, l+jets

173.49 ± 1.06 (0.43 ± 0.97) 7 TeV [9]

CMS, dilepton

172.50 ± 1.52 (0.43 ± 1.46) 7 TeV [10]

CMS, all jets

173.49 ± 1.41 (0.69 ± 1.23) 7 TeV [11]

CMS, l+jets

172.35 ± 0.51 (0.16 ± 0.48) 8 TeV [12]

CMS, dilepton

172.82 ± 1.23 (0.19 ± 1.22) 8 TeV [12]

CMS, all jets

172.32 ± 0.64 (0.25 ± 0.59) 8 TeV [12]

CMS, single top

172.95 ± 1.22 (0.77 ± 0.95) 8 TeV [13]

CMS comb. (Sep 2015)

172.44 ± 0.48 (0.13 ± 0.47) 7+8 TeV [12]

CMS, l+jets

172.25 ± 0.63 (0.08 ± 0.62) 13 TeV [14]

CMS, dilepton

172.33 ± 0.70 (0.14 ± 0.69) 13 TeV [15]

CMS, all jets

172.34 ± 0.73 (0.20 ± 0.70) 13 TeV [16]

[1] ATLAS-CONF-2013-102 [2] arXiv:1403.4427 [3] EPJC 75 (2015) 330 [4] EPJC 75 (2015) 158 [5] ATLAS-CONF-2014-055 [6] PLB 761 (2016) 350

[7] JHEP 09 (2017) 118 [8] EPJC 79 (2019) 290 [9] JHEP 12 (2012) 105 [10] EPJC 72 (2012) 2202 [11] EPJC 74 (2014) 2758 [12] PRD 93 (2016) 072004

[13] EPJC 77 (2017) 354 [14] EPJC 78 (2018) 891 [15] EPJC 79 (2019) 368 [16] EPJC 79 (2019) 313

Many new measurement available, no world combination update yet. ATLAS in 2018, CMS in 2015

History of M _top : measuremnt, prediction, and SM global fit