Standard Model precision measurements Misure di precisione del modello standard

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Standard Model precision measurements Misure di precisione del modello standard

Lesson 4: Higgs

Stefano Lacaprara

INFN Padova

Dottorato di ricerca in fisica

Universit` a di Padova, Dipartimento di Fisica e Astronomia Padova, May 14, 2020

Stefano Lacaprara (INFN Padova) Fit SM Padova May 14, 2020 1/93

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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) (MZ αs

2) (MZ (5) αhad

∆ mt

b R0 c R0 0,b AFB

0,c AFB

Ab Ac (Tevt.) lept Θeff sin2

) FB lept(Q Θeff sin2

(SLD) Al

(LEP) Al

0,l AFB

lep R0

0 σhad ΓZ MZ ΓW MW MH

Global EW fit Indirect determination Measurement GfitterSM

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 ^had ₀

I sin ² θ ^lept _eff

I Asymmetries (2)

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 )

Stefano Lacaprara (INFN Padova) Fit SM Padova May 14, 2020 2/93

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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 ^had ₀

I

sin ² θ ^lept _eff

I

Asymmetries (2)

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 )

Stefano Lacaprara (INFN Padova) Fit SM Padova May 14, 2020 2/93

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Outline

1 Z-pole observables Standard Model Z lineshape

2 Asymmetries

3 W mass and width

4 Top mass

5 Higgs mass and features

6 Global ElectroWeak fit

Stefano Lacaprara (INFN Padova) Fit SM Padova May 14, 2020 3/93

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Outline

1 Z-pole observables

2 Asymmetries

Forward-Backward Asymmetries Left-Right Asymmetries

Tau polarization

3 W mass and width

4 Top mass

5 Higgs mass and features

6 Global ElectroWeak fit

Stefano Lacaprara (INFN Padova) Fit SM Padova May 14, 2020 4/93

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Outline

1 Z-pole observables

2 Asymmetries

3 W mass and width Motivation At LEP II

At Tevatron and LHC

4 Top mass

5 Higgs mass and features

6 Global ElectroWeak fit

Stefano Lacaprara (INFN Padova) Fit SM Padova May 14, 2020 5/93

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Outline

1 Z-pole observables

2 Asymmetries

3 W mass and width

4 Top mass

General technique Lepton plus jets Dileptons

5 Higgs mass and features

6 Global ElectroWeak fit

Stefano Lacaprara (INFN Padova) Fit SM Padova May 14, 2020 6/93

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Outline

1 Z-pole observables

2 Asymmetries

3 W mass and width

4 Top mass

5 Higgs mass and features Searches and Discovery Mass

Width Spin Coupling

6 Global ElectroWeak fit

Stefano Lacaprara (INFN Padova) Fit SM Padova May 14, 2020 7/93

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Searches at LEP

Dominating production mode at LEP (I and II) was the Higgs-stralung .

Direct production ee → H possible

I H coupling to fermion ∝ m ^f

→ negligible to e ^±

Second process is WW fusion

Higgstralhung drops when the available

√ s > M Z + M H :

I √

s = 206 GeV

I M _H ≤ 115 GeV

I Higgstralhung wall

dominant H decay into H → b¯b

e−

e+ Z⁰

Z⁰

H e−

e⁺

νe

νe H

Stefano Lacaprara (INFN Padova) Fit SM Padova May 14, 2020 8/93

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Final states considered: ZH H → b¯b ,

Z → q ¯ q, high BR Z → ``, clean, low BR Z → νν, invisible Z

Analysis based on H → bb invariant mass, b-tagging, NN, L, . . .

For M _H = 115 seen 17 events

I

(with S /B > 0.2) expected background 15.8

I

SM higgs signal 8.4

Stefano Lacaprara (INFN Padova) Fit SM Padova May 14, 2020 9/93

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Most significant events

Including ALEPH 4 jets

Stefano Lacaprara (INFN Padova) Fit SM Padova May 14, 2020 10/93

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4 experiments results

Q = L(data|s + b)

L(data|b) , −2 ln Q negative means that (s+b) preferred (ALEPH)

Stefano Lacaprara (INFN Padova) Fit SM Padova May 14, 2020 11/93

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4 channels

Stefano Lacaprara (INFN Padova) Fit SM Padova May 14, 2020 12/93

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LEP final results

LEP II excludes a SM Higgs Boson with M _H ≤ 114.4 GeV 95% CL (expected 115.3 GeV ) LEP I excluded up to 65 GeV

Stefano Lacaprara (INFN Padova) Fit SM Padova May 14, 2020 13/93

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Searches at Tevatron

Main production modes:

I gluon fusion (gg → H);

I associated production (Higgstralhung) Z/W → Z /WH;

Searches in associated production for additional tagging;

final states

I WH → e/µ + bb

I ZH → ee/µµ + bb

I ZH → νν + bb

I gg → H → WW → eνeν/µνµν/eνµν

b-tagging, multivariate technique, similar to LHC;

Stefano Lacaprara (INFN Padova) Fit SM Padova May 14, 2020 14/93

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Tevatron results

Background subtracted M bb

(CDF+D0)

Background subtracted discriminant for all channels

Background an signal vs S/B for all Higgs channel

Stefano Lacaprara (INFN Padova) Fit SM Padova May 14, 2020 15/93

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Tevatron results per channel

ln L for H → WW

2 ) (GeV/c m H

100 110 120 130 140 150 160 170 180 190 200

Log-Likelihood Ratio

-10 0 10 20 30 40

50 LLR

_b

± 1 s.d.

2 s.d.

± LLR

b

LLR

b

LLR

s+b

LLR

Obs

2

)

=125 GeV/c 1.0 (m

H

× σ

2

)

=125 GeV/c 1.5 (m

H

× σ

10 fb

-1

≤ Tevatron Run II, L

int

WW Combination SM H →

ln L for H → bb

LLR _b : background-only; LLR _s+b : signal+background;

σ H : LLR espected if SM σ for M H = 125 GeV

H → WW most sensitive to M H ∼ 2M W ∼ 165 GeV, H → bb lower mass, no contribution from H → γγ/ττ

Stefano Lacaprara (INFN Padova) Fit SM Padova May 14, 2020 16/93

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Tevatron combined results

Expected and observed CL limit p-value

p −value is probability that the data observed is due only to a fluctuation of the expected background. Lower p-value is 3σ

Stefano Lacaprara (INFN Padova) Fit SM Padova May 14, 2020 17/93

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Discovery at LHC: 4 July 2012. ATLAS

H → γγ H → ZZ → 4`

Stefano Lacaprara (INFN Padova) Fit SM Padova May 14, 2020 18/93

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Discovery at LHC: 4 July 2012. CMS

H → γγ H → ZZ → 4`

Stefano Lacaprara (INFN Padova) Fit SM Padova May 14, 2020 19/93

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CMS: H → γγ split by category

Stefano Lacaprara (INFN Padova) Fit SM Padova May 14, 2020 20/93

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ATLAS and CMS combined H → γγ, ZZ → 4` p-value

Stefano Lacaprara (INFN Padova) Fit SM Padova May 14, 2020 21/93

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Moving on

Today dicovery of the Higgs boson is established w/o doubt major effort it to establish/measure Higgs properties:

Is it the SM Higgs or not?

Mass Width Spin

Coupling to fermions/bosons

Exploit all possible production and decay channels

Stefano Lacaprara (INFN Padova) Fit SM Padova May 14, 2020 22/93

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Production mecahnism at LHC

gg → H gluon fusion :

I Highest cross-section but “isolated” production, no associated objects.

VBF vector boson fusion:

I Presence of two forward-backward associated jets;

VH associated with vector boson:

I Clear signature from V = Z /W decay;

ttH/ bbH top-associated production:

I Rich experimental signature, but low cross-section.

Stefano Lacaprara (INFN Padova) Fit SM Padova May 14, 2020 23/93

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Cross section for M _H =125 GeV

√ s 7 TeV 8 TeV 13 TeV

Process σ [pb]

gg → H 15.13 19.27 43.92

VBF 1.222 1.578 3.748

WH 0.5785 0.7046 1.380

ZH 0.3351 0.4153 0.8696

ttH 0.08632 0.1293 0.5085 bbH 0.1558 0.2035 0.5116

Frequently-asked-question:

Q) Why gains in gg→H and qq→qqH are the same? A) accidental!

Q) Why ttH gain is so large? A) phase space opening + large MX=2Mt+MH in gg) Gains can be estimated via parton luminosity ratio if kinematically fully open.

Cross section ratio σ 14TeV /σ 8TeV

10 100 1000 10000

1 10 100 1000

gg Σqq

WJS2012

ratios of LHC parton luminosities:

14 TeV / 8 TeV and 33 TeV / 8 TeV

luminosity ratio

M_X (GeV)

MSTW2008NLO _

σ(14TeV)/σ(8TeV) gg→H 2.6 (MX=MH) qq→qqH 2.6 (probes high MX) qq→VH 2.1 (MX=MV+MH)

gg→ttH 4.7 (phase space+MX)

12

European Strategy 2012 TWki

0.1 1 10

10^-7 10^-6 10^-5 10^-4 10^-3 10^-2 10^-1 10⁰ 10¹ 10² 10³ 10⁴ 10⁵ 10⁶ 10⁷ 10⁸ 10⁹

σσ σσ

WH(M

H=125 GeV)

HE LHC

WJS2012 σ σ σ

σjet(E_T^jet > 100 GeV) σ σ σ σjet(E_T^jet > √√√√s/20)

σ σ σ σggH(M_H=125 GeV)

LHC Tevatron

e v e n ts / s e c f o r L = 1 0

33

c m

-2

s

-1 σ

σσ σb σ σ σ σtot

proton - (anti)proton cross sections

σ σ σ σW σ σ σ σZ

σ σ σ σt

σ σ σ σ ((((

n b

))))

√

√√

√ s (TeV)

Stefano Lacaprara (INFN Padova) Fit SM Padova May 14, 2020 24/93

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Decay

M _H =125 GeV is a gift from nature: many different decay channels are available

[GeV]

M H

80 100 120 140 160 180 200

Higgs BR + Total Uncert

10 -4

10 -3

10 -2

10 -1

1

LHC HIGGS XS WG 2013

b b

τ τ

µ µ c c

gg

γ

γ Z γ

WW

ZZ

Stefano Lacaprara (INFN Padova) Fit SM Padova May 14, 2020 25/93

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Decay channel exploited

H → bb B =57.7%

I

very difficult for QCD b background;

H → ττ B =6.3%

I

marginally better;

H → WW B =21.5%

I

W → `ν easy, but 2 ν in the final state;

H → ZZ B =2.6%

I

Z → 2`: golden channel;

H → γγ B =0.228%

I

via loop, low BR, but M γγ peak visible;

H → invisible B =0%

I

visible only in associated production;

Stefano Lacaprara (INFN Padova) Fit SM Padova May 14, 2020 26/93

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What have been searched for

H → γγ ZZ WW bb τ τ µµ inv.

gg → H 3 3 3 3 3 3 3

VBF 3 3 3 3 3 3 3

VH 3 3 3 3 3 7 3

ttH 3 3 3 3 7 7 7

Basically all possible production/decay channels have been used;

Some (eg H → µµ) has expected yield 1 with current luminosity;

Stefano Lacaprara (INFN Padova) Fit SM Padova May 14, 2020 27/93

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H → γγ: CMS [1, 2]

Small peak over rapidly falling continuous background;

key element is ECAL resolution and stability;

I Use Z → ee sample to calibrate and monitor ECAL response;

I CMS has 1 − 1.7 X ⁰ in front of ECAL: γ conversion reconstruction is crucial;

I BDT γ-jet to identify γ vertex identification;

I problematic with high PU;

I combine info on tracking recoiling against γγ system

I and γ conversion pointing direction.

Many event categories

I according to γ ID (MVA)

I production channel (kineamtics)

F tH, VH, ttH, VBF, untagged;

I associated object decay: leptonic, hadronic, MET

weighted (w = S/(S + B)) sum of all categories.

S/(S+B) Weighted Events / GeV ₀ 5000 10000 15000 20000 25000 30000 35000

Data S+B fit B component

σ

±1 σ

±2 S/(S+B) weighted All categories

-- Preliminary

CMS

77.4 fb^-1 (13TeV)

γ γ

→ H

(GeV) γ mγ

100 110 120 130 140 150 160 170 180

−500 0 500

1000 B component subtracted

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Many categories . . . (run I [1])

Events / GeV

0 2 4 6 8 10

σ

±1 σ

±2 VBF 0

=1.18 µ

=125.4 GeV, mH

--

CMS 35.9 fb^-1 (13TeV)

γ γ

→ H

(GeV) γ mγ

100 110 120 130 140 150 160 170 180

−4

−2 0 2 4 6

Events / GeV

0 2 4 6 8 10 12 14 16 18

σ

±1 σ

±2 VBF 1

=1.18 µ

=125.4 GeV, mH

--

CMS 35.9 fb^-1 (13TeV)

γ γ

→ H

(GeV) γ mγ

100 110 120 130 140 150 160 170 180

−5 0 5

Events / GeV

0 10 20 30 40 50 60 70 80

σ

±1 σ

±2 VBF 2

=1.18 µ

=125.4 GeV, mH

--

CMS 35.9 fb^-1 (13TeV)

γ γ

→ H

(GeV) γ mγ

100 110 120 130 140 150 160 170 180

−20

−10 0 10

Events / GeV

0 2 4 6 8 10 12

σ

±1 σ

±2 ttH Leptonic

=1.18 µ

=125.4 GeV, mH

--

CMS 35.9 fb^-1 (13TeV)

γ γ

→ H

(GeV) γ mγ

100 110 120 130 140 150 160 170 180

−4

−2 0 2 4 6

Events / GeV

0 2 4 6 8 10 12 14

σ

±1 σ

±2 ttH Hadronic

=1.18 µ

=125.4 GeV, mH

--

CMS 35.9 fb^-1 (13TeV)

γ γ

→ H

(GeV) γ mγ

100 110 120 130 140 150 160 170 180

−5 0 5

Events / GeV

0 0.5 1 1.5 2 2.5 3 3.5 4

σ

±1 σ

±2 ZH Leptonic

=1.18 µ

=125.4 GeV,

mH --

CMS 35.9 fb^-1 (13TeV)

γ γ

→ H

(GeV) γ mγ

100 110 120 130 140 150 160 170 180

−1 0 1 2 3

Events / GeV

0 2 4 6 8 10 12

σ

±1 σ

±2 WH Leptonic

=1.18 µ

=125.4 GeV,

mH --

CMS 35.9 fb^-1 (13TeV)

γ γ

→ H

(GeV) γ mγ

100 110 120 130 140 150 160 170 180

−42

− 0 2 4 6

Events / GeV

0 2 4 6 8 10 12 14 16 18 20

σ

±1 σ

±2 VH Leptonic Loose

=1.18 µ

=125.4 GeV,

mH --

CMS 35.9 fb^-1 (13TeV)

γ γ

→ H

(GeV) γ mγ

100 110 120 130 140 150 160 170 180

−5 0 5 10

Events / GeV

0 2 4 6 8 10 12 14 16 18

σ

±1 σ

±2 VH MET

=1.18 µ

=125.4 GeV,

mH --

CMS 35.9 fb^-1 (13TeV)

γ γ

→ H

(GeV) γ mγ

100 110 120 130 140 150 160 170 180

−5 0 5

Events / GeV

0 5 10 15 20 25 30

σ

±1 σ

±2 VH Hadronic

=1.18 µ

=125.4 GeV,

mH --

CMS 35.9 fb^-1 (13TeV)

γ γ

→ H

(GeV) γ mγ

100 110 120 130 140 150 160 170 180

−10

−5 0 5 10

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H → γγ categories breakdown [1]

10 20 30 40 50 60 70 80 90 100

0 2 4 6 8 10 12

ggH VBF ttH bbH tHq tHW

WH leptonic ZH leptonic WH hadronic ZH hadronic

0 0.5 1 1.5 2 2.5

σeff σ_HM

0 0.1 0.2 0.3 0.4 0.5

S/(S+B) Untagged 0 32.5 expected events

Untagged 1 469.3 expected events

VBF 0 9.3 expected events

ttH Hadronic 5.6 expected events

ttH Leptonic 3.8 expected events

ZH Leptonic 0.5 expected events

WH Leptonic 3.6 expected events

VH LeptonicLoose 2.7 expected events

VH Hadronic 7.9 expected events

VH MET 4.0 expected events

Signal fraction (%) Width (GeV) S/(S+B) in ± σ

_eff

γ

→ H Simulation

CMS 35.9 fb

^-1

(13 TeV)

Different categories have different M γγ resolution, S /(S + B), and are sentitive to different production mechanism (small to bbH)

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H → γγ: CMS results [1]

µ = 1.16 ± 0.11(stat) ± 0.09(syst) ± 0.06(th)

= 1.16 ^+0.15 _−0.14

(was ± 0.25 at 7 + 8 TeV)

µ

0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 1.5 1.6

ln L∆-2

0 1 2 3 4 5 6

stat+syst stat only

−0.140.17 = 1.18 + µ

68% CL 95% CL

CMS γ γ

→ H

(13TeV) 35.9 fb-1

profiled mH

individual prod channel significance:

ggH 5σ, VBF 1.1σ, ttH 3.3σ, VH 2.5σ

σtheo proc/ σ

−2 0 2 4 6 8

-0.0+1.7 0.0 qqH other

-0.0 0.0 +0.7

qqH 3J-like

-0.5 1.3 +0.6

qqH 2J-like

-0.0 0.0 +0.5

ggH VBF-like

-1.2 2.8 +1.1

ggH 2J BSM

-0.6 0.6 +0.8

ggH 2J high

-1.1 2.7 +1.0

ggH 2J med

-0.3 0.3 +1.4

ggH 2J low

-1.5 1.8 +1.6

ggH 1J BSM

-0.7 2.0 +1.0

ggH 1J high

-0.4 0.5 +0.5

ggH 1J med

-0.6+0.7 1.5 ggH 1J low

-0.20 +0.20 1.17 ggH 0J

profiled mH Observation

SM Prediction Preliminary

CMS γ γ

→ H

TeV) -1 (13 77.4 fb

σtheo proc/ σ

−2 0 2 4 6 8

-2.3 5.1 +2.5

VH hadronic

-0.0 0.0 +0.9

ZH leptonic

-1.3 3.0 +1.5

WH leptonic

-0.7 2.0 +0.8

H t t

-0.5 0.8 +0.6

VBF

-0.18 +0.19 1.02

ggH

profiled mH

Per process 68% CL SM Prediction

CMS

γ γ

→ H

TeV) -1 (13 35.9 fb

µ

−2 0 2 4 6 8

-1.0 2.4 +1.1

VH

-0.8 2.2 +0.9

H t t

-0.5 0.8 +0.6

VBF

-0.18 +0.20 1.10 ggH

−0.14 +0.17 = 1.18 combined µ

profiled mH

Combined 68% CL Per process 68% CL

µSM µ=

CMS

γ γ

→ H

TeV)

-1 (13 35.9 fb

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H → γγ: ATLAS results [3]

Fraction of Signal Process / Category 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 ggH 0J CEN

ggH 0J FWD ggH 1J LOW ggH 1J MED ggH 1J HIGH ggH 1J BSM ggH 2J LOW ggH 2J MED ggH 2J HIGH ggH 2J BSM HjjT VBF loose, low p

HjjT VBF tight, low p

HjjT VBF loose, high p

HjjT VBF tight, high p

VH had loose VH had tight jet BSM VH MET LOW VH MET HIGH VH lep LOW VH lep HIGH VH dilep tH had 4j2b tH had 4j1b ttH had BDT4 ttH had BDT3 ttH had BDT2 ttH had BDT1 ttH lep tH lep 1fwd tH lep 0fwd

ATLAS Simulation

H→γγ, m_H = 125.09 GeV

ggH VBF WH ZH ggZH ttH bbH tHq tHW

similar analysis, even more categories (32), sensitive to different prod. channel

Signal strength

0 1 2 3 4 5 6 7

Run-1

μ

Run-2

μ

ggH

μ

VBF

μ

VH

μ

top

ATLAS = 13 TeV, 36.1 fb

-1

s Total Stat.

Total Stat. Exp. Theo.

0.08

− 0.12 0.08+

− 0.10 0.23+

− 0.23 0.26 +

− 0.28

= 1.17

+ Run-1

μ

ggH @ NNLO

0.05

− 0.07 0.05+

− 0.06 0.12+

− 0.12 0.14 +

− 0.15

= 0.99

+ Run-2

μ

3LO ggH @ N

0.05

− 0.07 0.06+

− 0.07 0.16+

− 0.16 + 0.18

− 0.19

= 0.81

+

μ

ggH

0.2

− 0.3 0.2 +

− 0.3 0.5 +

− 0.5 + 0.5

− 0.6

= 2.0

+

μ

VBF

0.1

− 0.2 0.2 +

− 0.2 0.8 +

− 0.8 + 0.8

− 0.9

= 0.7

+

μ

VH

0.0

− 0.1 0.1 +

− 0.1 0.5 +

− 0.6 + 0.6

− 0.6

= 0.5

+

μ

top

= 125.09 GeV m

H

, γ γ H →

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H → γγ: differential cross section CMS [4], ATLAS [3]

Signal so clean that differential dσ/dp _T ,dσ/N _jets possible

[GeV]

γ γ

pT

(fb/GeV)

γγ T

/dp

fid

σ d

−3

10

−2

10

−1

10 1 10 10

2

Data ggH aMC@NLO + HX

ggH POWHEG + HX HX aMC@NLO

Preliminary

CMS 35.9 fb

^-1

(13TeV)

γγ T) dpγγ T(pfidσ

∞ 350

∫

310

=125.09 GeV H LHC HXSWG YR4, m

γ γ

→ H

(GeV)

γ γ

p

T

0 50 100 150 200 250 300 350 400

Ratio to aMC@NLO + HX 0 0.5 1 1.5 2 2.5

1 10 10

2

10

3

[fb]

fid

σ

ATLAS

Data, tot. unc.

= 13 TeV, 36.1 fb-1

,

s

γ γ

H→

Syst. unc.

> 30 GeV pT

= 0.4,

tR k anti

XH default MC +

→H gg

XH N3LO +

XH N3LO+JVE +

XH STWZ, BLPTW +

XH NNLOJET +

XH Powheg NNLOPS +

XH GoSam+Sherpa +

XH ) + MEPS@NLO Sherpa (

XH MG5 aMC@NLO +

bbH + ttH + VH = VBF+

XH

=0 =1 =2 ≥ 0 ≥ 1 ≥ 2 ≥ 3

Njets 0

1 2

XHRatio to default MC +

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H → ZZ CMS [5]: golden channel

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Signal fraction tagged

H-leptonic t t tagged

H-hadronic t t

tagged VH-MET tagged VH-leptonic tagged VH-hadronic

tagged VBF-2jet tagged VBF-1jet

Untagged ^ggHVBF

→X WH, W

ν l

→ WH, W

X

→ ZH, Z

l 2

→ ZH, Z

+X l 0

→ t H, t t t

l+X

→1 t H, t t t

+X l 2

→ t H, t t t H b b tH 183.95 exp. events

17.61 exp. events 13.80 exp. events 7.54 exp. events 1.73 exp. events 0.00 exp. events 1.19 exp. events 0.70 exp. events

(13 TeV) 137.1 fb-1

CMSSimulation Preliminary

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Signal fraction tagged

H-leptonic t t tagged

H-hadronic t t

tagged VH-MET tagged VH-leptonic tagged VH-hadronic

tagged VBF-2jet tagged VBF-1jet

Untagged ^ggH_VBF

X

→ WH, W

ν l WH, W→

→X ZH, Z

l

→2 ZH, Z

+X l 0

→ t H, t t t

+X l 1

→ t H, t t t

+X l 2

→ t H, t t t H b b tH 183.95 exp. events

17.61 exp. events 13.80 exp. events 7.54 exp. events 1.73 exp. events 0.00 exp. events 1.19 exp. events 0.70 exp. events

(13 TeV) 137.1 fb-1

CMSSimulation Preliminary

four `, high p _T , isolated: eeee, eeµµ, µµµµ

I narrow peak (M ```` , σ ∼ 1 − 2%)

I handy Z → 4` peak to calibrate lepton scale and resolution

I one Z on-shell (other Z ^? )

I (small) background from ZZ and Z + X use also p _T ^4` and angular correlations between ` ggF, VBF, VH

(GeV)

4l

m 0

50 100 150 200 250 300 350

Events / 4GeV

Data H(125)

γ* ZZ, Z

→ q q

γ* ZZ, Z

→ gg Z+X

(13 TeV) 137.1 fb-1 Preliminary 2016 + 2017 + 2018

CMS

80 100 200 300 400 500 700 1000

80 100 120 140 160

(GeV)

l

m4 0

20 40 60 80 100 120 140 160 180 200 220 240

Events / 2GeV

Data H(125)

γ* ZZ, Z

→ q q

γ* ZZ, Z

→ gg Z+X

(13 TeV) 137.1 fb-1 Preliminary 2016 + 2017 + 2018 CMS

40 50 60 70 80 90 100 110 120

(GeV)

Z1

m 20

40 60 80 100 120

(GeV)2Zm

0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18

Events / bin

4e µ 4

µ 2e2

< 130 GeV l 118 < m4

(2018 13 TeV) 59.7 fb-1 Preliminary

CMS

Stefano Lacaprara (INFN Padova) Fit SM Padova May 14, 2020 34/93

(36)

H → ZZ : MELA [5]

Matrix Element Likelihood Analysis

Fully use the polarization information of the H → ZZ ^? → `` + `` decay;

define 5 uncorrelated angles which fully determines the decay kinematics;

using ME build probabily for S and B (ZZ) then build likelihood-ratio discriminant D ^kin very sensitive to J ^P of initial state

(GeV)

4l

m

100 110 120 130 140 150 160 170

kin bkg

D

0 0.2 0.4 0.6 0.8 1 1.2

Events / bin

0 0.2 0.4 0.6 0.8 1 1.2 4e

µ 4

µ 2e2

untagged VBF-1j tagged VBF-2j tagged

VH-hadr. tagged VH-lept. tagged

tagged

miss

VH-ET

H tagged t t

(13 TeV) 35.9 fb-1

CMS

Stefano Lacaprara (INFN Padova) Fit SM Padova May 14, 2020 35/93

(37)

H → ZZ : Results [5]

µ = 0.94 ± 0.07(stat.) ± 0.08(syst.) differential cross section

I vs √

s, p ^H _T , N jets , p _T ^jet

also direct limit on Γ _H < 1.1 GeV @95% CL

(TeV) s

6 7 8 9 10 11 12 13 14

(fb)fidσ

0 1 2 3 4 5 6

sys. unc.) Data (stat. ⊕ Systematic uncertainty Standard model

=125.09 GeV LHC HXSWG YR4, mH

(13 TeV) (8 TeV), 137.1 fb-1 (7 TeV), 19.7 fb-1 5.1 fb-1

CMS

4l) + X

→

→ (H pp

(H) (fb/GeV)T/dpfid σd

−4 10

−3 10

−2 10

−1 10

1 Data (stat. ⊕ sys. unc.)

Systematic uncertainty H (NNLOPS) + XH

→ gg

H (POWHEG) + XH

→ gg XH = VBF + VH + ttH (POWHEG)

=125.09 GeV) H (LHC HXSWG YR4, m

(13 TeV) 137.1 fb-1

CMSPreliminary

(H) > 200 GeV)T(pσ501

(H) (GeV) pT

0 50 100 150 200 250

Ratio to NNLOPS 00.20.40.6 0.81 1.2 1.4

/d|y(H)| (fb)fid σd

0.5 1 1.5 2 2.5 3 3.5 4 4.5

sys. unc.)

⊕ Data (stat.

Systematic uncertainty H (NNLOPS) + XH

→ gg

H (POWHEG) + XH

→ gg XH = VBF + VH + ttH (POWHEG)

(13 TeV) 137.1 fb-1

|y(H)|

0 0.5 1 1.5 2 2.5

Ratio to NNLOPS 00.20.40.60.811.21.41.6

(fb)fidσ

−2 10

−1 10 1 10

102 Data (stat. ⊕ sys. unc.)

Systematic uncertainty H (NNLOPS + Pythia) + XH

→ gg

H (POWHEG + Pythia) + XH

→ gg

XH = VBF + VH + ttH (POWHEG + Pythia)

(13 TeV) 137.1 fb-1

(jet)| < 2.5 (jet) > 30 GeV, |η pT

N(jets)

0 1 2 3 ≥ 4

Ratio to NNLOPS 00.20.40.60.8 1 1.2 1.4

[GeV]

Γ

H

0 0.5 1 1.5 2 2.5 3

lnL ∆ -2

0 2 4 6 8 10

(13 TeV) 35.9 fb-1

68% CL 95% CL Observed

Expected

(GeV)

σ

SM

σ /

0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5

-0.13 +0.92 0.13 H,tH t t

-0.72 +0.90 1.13 VH

-0.36 +0.47 0.62 VBF

-0.11 +0.11 0.96 H b ggH,b

0.06 (fb) σSM

→4l

→ZZ H

0.27 0.45 5.55 profiled mH

(13 TeV) 137.1 fb-1

Stefano Lacaprara (INFN Padova) Fit SM Padova May 14, 2020 36/93

(38)

H → ZZ : ATLAS [6, 7]

Very similar analysis mostly sensitive to ggF

differential cross section also measured tensor structure of SM studied (2HDM) µ = 1.29 ± 0.18 ± 0.8 (µ VBF is a bit high)

80 90 100 110 120 130 140 150 160 170 [GeV]

m

4l

0 20 40 60 80 100 120 140 160 180

Events/2.5 GeV

Data Higgs (125 GeV) Z(Z*) tXX, VVV

t Z+jets, t Uncertainty

ATLAS

→ 4l ZZ*

→ H s = 13 TeV, 139 fb-1

Bin 0 Bin 1 Bin 2 Bin 3 Bin 4

vs. m

34

m

12

0 20 40 60 80 100 120 140 160 180

Events

5060708090100 110 [GeV]

m12 10 20 30 40 50 [GeV]m3460

Data Signal Background

Bin 0 Bin 1

Bin 2

Bin 3 Bin 4

Data Higgs (125 GeV) ZZ*

tXX, VVV t Z+jets, t Uncertainty

ATLAS

→ 4l ZZ*

→ H s = 13 TeV, 139 fb-1

< 130 GeV m4l 115 <

Expected Composition

Reconstructed Event Category

-enriched ttH -Lep-enriched VH

-Had-enriched VH

-High j pT VBF-enriched- j-Low pT VBF-enriched- -High 4l pT - j 1

-Med 4l pT - j 1

4l-Low pT - j 1

j 0

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

j ggF-0 -Low H T p - j ggF-1 H-Med T p - j ggF-1

-High H pT j- ggF-1 j ggF-2

j-Low T p VBF- -High j pT VBF- -Had VH

-Lep VH ttH bbH ATLAS Simulation

4l ZZ* → H → 13 TeV, 36.1 fb-1

0 2 4 6 8 10

)SM B

⋅ /(σ B

⋅ σ ttH

-Lep VH

-Had VH

-High j T p VBF-

j-Low pT VBF-

j ggF-2 -High H pT - j ggF-1

H-Med pT - j ggF-1

-Low H T p - j ggF-1

j ggF-0

[fb]

B

⋅

σ [fb]

SM ) B

⋅ (σ

(95% CL)

< 110 1.6

− 1.1 15.4+ /5

(95% CL)

< 160 1.4

− 0.8 16.6+ /5

(95% CL)

< 200 3.3

− 1.9 36.2+ /5

40

− 50

60+ −_0.2

0.4 4.2+ /5

150

− 180 260+ 88.6 ± 2.7

140

− 160

200+ 140 ± 30

40

− 50 30+ 24 ± 5

90

− 110

160+ 120 ± 20

140

− 150 80+ 170 ± 25

210

− 240

880+ 730 ± 50

4l ZZ* → H → 13 TeV, 36.1 fb-1

| < 2.5 H Reduced Stage 1 - |y

ATLAS Expected SM Observed: Stat + Sys SM Prediction

Stefano Lacaprara (INFN Padova) Fit SM Padova May 14, 2020 37/93

(39)

H → WW

Large B, consider W → `ν (B =10%) prod: gg/VBF/VH ∼ 25/1/1.4;

clean final state, but with 2 ν.

I No M WW reconstruction possible

I reconstruct M `` mass

I and M T = q

2p ^`` _T E _T ^miss (1 − cos ∆φ) large background

Selection

I Opposite charge `, MET

I Use W polarization from H decay to reduce WW background

I control regions for background normalization categories for 0,1,2 jets, additional `s

Stefano Lacaprara (INFN Padova) Fit SM Padova May 14, 2020 38/93

(40)

H → WW : results CMS [8]

Signal extraction based on M _T , M _`` or ∆R _`` ^min (ZH)

many categories, as usual. . . significance 9.1σ (7.1 expected):

µ = 1.28 ± 0.18

Ch vs Prod

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 Signal fraction 4-lepton ZH-tagged

3-lepton WH-tagged 2-jet DF VH-tagged 2-jet DF VBF-tagged 2-jet DF ggH-tagged 1-jet SF ggH-tagged 1-jet DF ggH-tagged 0-jet SF ggH-tagged 0-jet DF ggH-tagged

ggH VBF WH ZH

H b b

H t t (13 TeV) 35.9 fb-1

CMSSimulation

2.7 events 5.6 events 19.6 events 31.2 events 103.3 events 92.7 events 313.3 events 240.3 events 509.4 events

[GeV]

mll

20 40 60 80

]-1 [GeVll/dmwdN

20 40 60 80 100 120

140 tW and tt WW

Nonprompt DY

VVV VZ

γ

V Vγ*

Higgs Data

Systematic uncertainty

(13 TeV) 35.9 fb-1 CMS

[GeV]

mll

20 40 60 80

Data/Expected0.6 0.8 1 1.2 1.4

[GeV]

mT

60 80 100 120 140

]-1 [GeVT/dmwdN

20 40 60 80 100 120 140 160 180 200 220 240

t

tW and t WW

Nonprompt DY

VVV VZ

γ

V Vγ*

Higgs Data

(13 TeV) 35.9 fb-1 CMS

[GeV]

mT

60 80 100 120 140

Rll

∆

0 1 2 3 min 4

)ll R∆dN/d(min

50 100 150 200 250 300

Nonprompt WW

VVV Vγ

ZZ WZ

Higgs Data

(13 TeV) 35.9 fb-1 CMS

Rll

∆ min

0 1 2 3 4

0 1 2 3 4 5 6

σSM

/ σ

-0.24 +0.21 = 1.38 ggH µ

-0.29 +0.66 = 0.29 µVBF

-1.70 +1.88 = 3.27 µWH

-1.00 +1.57 = 1.00 ZH µ

-0.17 +0.18 = 1.28 µcomb

WW H→

Combination

SM (13 TeV) 35.9 fb-1

CMS

Stefano Lacaprara (INFN Padova) Fit SM Padova May 14, 2020 39/93

(41)

H → WW : ATLAS results [5]

WW → eνµν, categories: N jets= 0, 1, ≥ 2 measured ggF as well as VBF cross section;

sensitive variable are: M _`` , M _T and p ^sublead _T (2 ^nd `) significance: ggF 6.3σ (7.1 expected) - VBF 1.9 (2.7) µ _ggF = 1.21 ± 0.22, µ VBF = 0.62 ± 0.36,

0 200 400 600 800 1000 1200 1400 1600 1800 2000

Events / 10 GeV

Data Uncertainty

HggF H_VBF /Wt t

t WW

γ*

Z/ Mis-Id

VV

ATLAS

≤ 1 Njet ν, µ ν

→e

→WW*

H = 13 TeV, 36.1 fb-1 s

60 80 100 120 140 160 180 200 220 240 [GeV]

mT 0

100 200 300

Data-Bkg.

10 15 20 25 30 35 40 45 50 55 60

[GeV]

mll

0 200 400 600 800 1000 1200 1400

Events / 5 GeV

Data Uncertainty HggF HVBF

/Wt t

t WW

γ*

Z/ Mis-Id

VV

ATLAS = 0 Njet ν, µ ν

→e

→WW*

H

= 13 TeV, 36.1 fb-1 s

10 15 20 25 30 35 40 45 50 55

[GeV]

l1

pt

0 200 400 600 800 1000 1200 1400

Events / 2.5 GeV

Data Uncertainty HggF HVBF

/Wt t

t WW

γ*

Z/ Mis-Id

VV

ATLAS = 0 Njet ν, µ ν

→e

→WW*

H

= 13 TeV, 36.1 fb-1 s

ggF vs VBF

SM σttH ttH/ 1 σ

− 0 1 2 3 4

Total Stat. Syst. SM

ATLAS = 13 TeV, 36.1 - 79.8 fb-1 s

Total Stat. Syst.

Combined 1.32 ± _0.26^0.28 ( ± 0.18 , ± _0.19^0.21 ) H (ZZ)

t

t < 1.77 at 68% CL

γ) γ H ( t

t 1.39 ± _0.42^0.48 ( ± _0.38^0.42 , ± _0.17^0.23 ) H (multilepton)

t

t 1.56 ± _0.40^0.42 ( ± _0.29^0.30 , ± _0.27^0.30 ) )

b H (b t

t 0.79 ± _0.600.61 ( ± _0.280.29 , ± 0.53 )

Stefano Lacaprara (INFN Padova) Fit SM Padova May 14, 2020 40/93

(42)

H → ττ

Direct probe of coupling to fermions;

sizeable B

I use all τ decay channel

I leptonic and hadronic

most powerful variable M _{τ τ} σ _M ∼ 10%

I M H =125 GeV close to M Z =91 GeV

I use kinematic fit of M τ τ using visible products and MET

I Z → ττ background estimated via Z → µµ and replacing µ ↔ τ

many categories according to production mechanism

I additional ` (VH);

I additional F-B jets (VBF);

I boosted topology;

I 0/1 jets;

as usual MVA selection (including M τ τ ) ^m

^τ^MMC^τ

^[GeV]

0 50 100 150 200

Fraction of Events / 5 GeV

0 0.02 0.04 0.06 0.08 0.1 0.12 0.14 0.16 0.18 0.2 0.22

τ τ

→ Z

τ τ

→ (125) H

ATLAS

had VBF

lepτ τ

) = 92.4 GeV τ τ

→ Z

peak( m

) = 123.2 GeV τ

τ

→ H

peak( m

30 %

peak≈ m FWHM/

Standard Model precision measurements Misure di precisione del modello standard