Understanding the Higgs Boson: Where We Are, Where Were Going, and - - PowerPoint PPT Presentation

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Imperial College London High Energy Physics Seminar 6 February 2019

Understanding the Higgs Boson: Where We Are, Where We’re Going, and How To Get There

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• S. Zenz - Higgs Seminar

6 February 2019

Foreword: Higgs Discovery

2

I think we did it! We have a discovery.

July 4, 2012

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• S. Zenz - Higgs Seminar

6 February 2019

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As a layman, we have it, but as a scientist, we have to find out what sort

• f Higgs boson it is.

July 4, 2012

Foreword: Higgs Discovery

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• S. Zenz - Higgs Seminar

6 February 2019

Preface: Climbing the Peaks

• How do we get from discovery to measurement?
• How do we get from ideas to finished analyses?

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• S. Zenz - Higgs Seminar

6 February 2019

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• How do we get from discovery to measurement?
• How do we get from ideas to finished analyses?

Preface: Climbing the Peaks

2008

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• S. Zenz - Higgs Seminar

6 February 2019

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• How do we get from discovery to measurement?
• How do we get from ideas to finished analyses?

“employing state-of-the-art jet reconstruction and decomposition techniques” “At high transverse momenta . . . these processes can be recovered as promising search channels for the standard model Higgs boson around 120 GeV in mass.”

Preface: Climbing the Peaks

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• S. Zenz - Higgs Seminar

6 February 2019

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• How do we get from discovery to measurement?
• How do we get from ideas to finished analyses?

“employing state-of-the-art jet reconstruction and decomposition techniques”

Preface: Climbing the Peaks

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• S. Zenz - Higgs Seminar

6 February 2019

Preface: Climbing the Peaks

• How do we get from discovery to measurement?
• How do we get from ideas to finished analyses?

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“employing state-of-the-art jet reconstruction and decomposition techniques”

X → ZZ → llqq CMS-PAS-HIG-16-034

• Phys. Lett. B 777 (2017) 91

X → VV → qqqq

JHEP 07 (2017) 001 X → tt → lepton+jets or fully hadronic

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• S. Zenz - Higgs Seminar

6 February 2019

Preface: Climbing the Peaks

“At high transverse momenta . . . these processes can be recovered as promising search channels for the standard model Higgs boson around 120 GeV in mass.”

2011-14

• How do we get from discovery to measurement?
• How do we get from ideas to finished analyses?

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• S. Zenz - Higgs Seminar

6 February 2019

Preface: Climbing the Peaks

“At high transverse momenta . . . these processes can be recovered as promising search channels for the standard model Higgs boson around 120 GeV in mass.”

… uses well-separated standard jets only

• How do we get from discovery to measurement?
• How do we get from ideas to finished analyses?

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• S. Zenz - Higgs Seminar

6 February 2019

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• Even if we know exactly where we’re going…
• How will we get there?
• And what will we learn along the way?

Preface: Climbing the Peaks

Björn “Dr. Bear” Penning

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• S. Zenz - Higgs Seminar

6 February 2019

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• Even if we know exactly where we’re going…
• How will we get there?
• And what will we learn along the way?

Preface: Climbing the Peaks

• Phys. Rev. Lett. 120 (2018) 071802

Gluon-gluon fusion! Björn “Dr. Bear” Penning

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• S. Zenz - Higgs Seminar

6 February 2019

Outline

• Why the Higgs boson?
• The Large Hadron Collider and Compact Muon Solenoid
• Higgs Properties → Analysis Strategy
• Production and decay modes
• Overview of H → ɣɣ (as an example)
• Where we are: what sort of Higgs Boson is it?
• Production and decay
• Differential measurements
• Where we’re going: the High Luminosity LHC (2026 and beyond)
• Analysis projections and measurements
• Higgs trilinear couplings
• How to get there, and what can we learn along the way?
• Measurements for Run 2 (2015-18) and Run 3 (2021-23)
• Stepping stones toward the HL-LHC

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• S. Zenz - Higgs Seminar

6 February 2019 14

• The Higgs boson is…
• … the biggest discovery at the Large

Hadron Collider so far

• … one of our best windows of

discovery for new particles and interactions

• Why? The Standard Model (SM) precisely

predicts Higgs interactions

Why the Higgs Boson?

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• S. Zenz - Higgs Seminar

6 February 2019 15

• The Higgs boson is…
• … the biggest discovery at the Large

Hadron Collider so far

• … one of our best windows of

discovery for new particles and interactions

• Why? The Standard Model (SM) precisely

predicts Higgs interactions

Why the Higgs Boson?

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• S. Zenz - Higgs Seminar

6 February 2019 16

• The Higgs boson is…
• … the biggest discovery at the Large

Hadron Collider so far

• … one of our best windows of

discovery for new particles and interactions

• Why? The Standard Model (SM) precisely

predicts Higgs interactions

Why the Higgs Boson?

Ordinary stuff

… but we know the SM doesn’t explain everything!

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• S. Zenz - Higgs Seminar

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• The Higgs boson is…
• … the biggest discovery at the Large

Hadron Collider so far

• … one of our best windows of

discovery for new particles and interactions

• Why? The Standard Model (SM) precisely

predicts Higgs interactions The Higgs field . . . …Interacts with gauge bosons to leave two massive vector bosons (V), a massless photon (ɣ) and a scalar Higgs boson (h) …Interacts with 3 generations of fermions ( f ), giving them each a mass proportional to its Higgs-fermion coupling

Why the Higgs Boson?

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• S. Zenz - Higgs Seminar

6 February 2019 18

• The Higgs boson is…
• … the biggest discovery at the Large

Hadron Collider so far

• … one of our best windows of

discovery for new particles and interactions

• Why? The Standard Model (SM) precisely

predicts Higgs interactions The Higgs field . . . …Interacts with gauge bosons to leave two massive vector bosons (V), a massless photon (ɣ) and a scalar Higgs boson (h) …Interacts with 3 generations of fermions ( f ), giving them each a mass proportional to its Higgs-fermion coupling Now that we know the Higgs mass, the SM predicts all interaction rates, so we can test:

• Decay Rates
• Production Cross Sections

Why the Higgs Boson?

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• S. Zenz - Higgs Seminar

6 February 2019 19

• The Higgs boson is…
• … the biggest discovery at the Large

Hadron Collider so far

• … one of our best windows of

discovery for new particles and interactions

• Why? The Standard Model (SM) precisely

predicts Higgs interactions

• Decay Rates
• Production Cross Sections σ

Why the Higgs Boson?

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• S. Zenz - Higgs Seminar

6 February 2019 20

• The Higgs boson is…
• … the biggest discovery at the Large

Hadron Collider so far

• … one of our best windows of

discovery for new particles and interactions

• Why? The Standard Model (SM) precisely

predicts Higgs interactions

• Decay Rates
• Production Cross Sections σ

bb 57.5% 휏휏 6.3%

Why the Higgs Boson?

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• S. Zenz - Higgs Seminar

6 February 2019 21

• The Higgs boson is…
• … the biggest discovery at the Large

Hadron Collider so far

• … one of our best windows of

discovery for new particles and interactions

• Why? The Standard Model (SM) precisely

predicts Higgs interactions

• Decay Rates
• Production Cross Sections σ

WW 21.6% ZZ 2.7% bb 57.5% 휏휏 6.3%

Why the Higgs Boson?

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• S. Zenz - Higgs Seminar

6 February 2019 22

• The Higgs boson is…
• … the biggest discovery at the Large

Hadron Collider so far

• … one of our best windows of

discovery for new particles and interactions

• Why? The Standard Model (SM) precisely

predicts Higgs interactions

• Decay Rates
• Production Cross Sections σ

WW 21.6% ZZ 2.7% bb 57.5% 휏휏 6.3% ɣɣ 0.2%

Why the Higgs Boson?

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• S. Zenz - Higgs Seminar

6 February 2019 23

• The Higgs boson is…
• … the biggest discovery at the Large

Hadron Collider so far

• … one of our best windows of

discovery for new particles and interactions

• Why? The Standard Model (SM) precisely

predicts Higgs interactions

• Decay Rates
• Production Cross Sections

ggF 87% VH 5% VBF 7% ttH 1%

Gluon-Gluon Fusion Vector Boson Fusion

Why the Higgs Boson?

Total cross section σH ~ 50 pb

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• S. Zenz - Higgs Seminar

6 February 2019 24

• The Higgs boson is…
• … the biggest discovery at the Large

Hadron Collider so far

• … one of our best windows of

discovery for new particles and interactions

• Why? The Standard Model (SM) precisely

predicts Higgs interactions

• Decay Rates
• Production Cross Sections
• Do the rates of these interactions agree

with the SM? If not, there are new particles and interactions!

Why the Higgs Boson?

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• S. Zenz - Higgs Seminar

6 February 2019 25

• The Higgs boson is…
• … the biggest discovery at the Large

Hadron Collider so far

• … one of our best windows of

discovery for new particles and interactions

• Why? The Standard Model (SM) precisely

predicts Higgs interactions

• Decay Rates
• Production Cross Sections
• Do the rates of these interactions agree

with the SM? If not, there are new particles and interactions!

• Ultimate challenge for this program: Higgs

self-coupling

Why the Higgs Boson?

σHH ~ 30 fb ~ 0.06% σH

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• S. Zenz - Higgs Seminar

6 February 2019 26

Why the Higgs Boson?

• The Higgs boson is…
• … the biggest discovery at the Large

Hadron Collider so far

• … one of our best windows of

discovery for new particles and interactions

• Why? The Standard Model (SM) precisely

predicts Higgs interactions

• Decay Rates
• Production Cross Sections
• Do the rates of these interactions agree

with the SM? If not, there are new particles and interactions!

• Ultimate challenge for this program: Higgs

self-coupling

Inflation,

High-energy stability of SM ?

σHH ~ 30 fb ~ 0.06% σH

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• S. Zenz - Higgs Seminar

6 February 2019

Large Hadron Collider

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CMS ATLAS ALICE LHCb

!

p-p, Pb-Pb, p-Pb

!

p-p: √s = 7-8 TeV, 
 now 13 TeV, 
 ultimately ~14 TeV

!

Design luminosity: ~1034 cm-2 s-1

!

Run 1: 7.7⨉1033 cm-2 s-1

!

Run 2: 2.1⨉1034 cm-2 s-1

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• S. Zenz - Higgs Seminar

6 February 2019

Large Hadron Collider

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CMS ATLAS ALICE LHCb

!

p-p, Pb-Pb, p-Pb

!

p-p: √s = 7-8 TeV, 
 now 13 TeV, 
 ultimately ~14 TeV

!

Design luminosity: ~1034 cm-2 s-1

!

Run 1: 7.7⨉1033 cm-2 s-1

!

Run 2: 2.1⨉1034 cm-2 s-1

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• S. Zenz - Higgs Seminar

6 February 2019

Compact Muon Solenoid

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• S. Zenz - Higgs Seminar

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Object Reconstruction in CMS

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• S. Zenz - Higgs Seminar

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Luminosity

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1 ASU 1 0Dy 1 Jun 1 JuO 1 AuJ 1 6eS 1 2ct 1 1ov 1 Dec

DDte (87C)

20 40 60 80 100

7otDO ,nteJUDted LumLnoVLty (fb−1 )

× 50

DDtD included fUom 2010-03-30 11:22 to 2018-10-26 08:23 8TC 2010, 7 7e9, 45.0 pb−1 2011, 7 7e9, 6.1 fb−1 2012, 8 7e9, 23.3 fb−1 2015, 13 7e9, 4.2 fb−1 2016, 13 7e9, 41.0 fb−1 2017, 13 7e9, 49.8 fb−1 2018, 13 7e9, 68.2 fb−1 20 40 60 80 100

CMS ,ntegrDted LumLnosLty DelLvered, SS

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• S. Zenz - Higgs Seminar

6 February 2019

Higgs Analyses: Production and Decay

!

Complete detector signature created by the Higgs decay and the decay products of particles from the production process

!

Which analyses are possible?

!

Luminosity

!

Rate of detector signature

!

Rate of backgrounds

!

Tools for background rejection

!

Example from my work: H → ɣɣ

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• S. Zenz - Higgs Seminar

6 February 2019

H → ɣɣ Analysis Overview

• Maximize Signal-to-Background using mass: mγγ2 = 2E1E2(1 - cosΔα)
• Some photons have better energy resolutions than others
• Best measurements in central region of calorimeter
• Well-contained in calorimeter cells
• Avoid “cracks” in detector
• Tracking: conversions to e+e- in material, isolation, vertex selection
• Categorize events by resolution to maximize Signal-to-Background

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Best 2016 Category σ = 1.32 GeV Worst Category σ = 2.61 GeV

CMS-PAS-HIG-15-005

JHEP 11 (2018) 185

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• S. Zenz - Higgs Seminar

6 February 2019

Categorization

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• Classifier BDT’s independent of mɣɣ – fit in next step

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• S. Zenz - Higgs Seminar

6 February 2019

All Categories

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• Classifier BDT’s independent of mɣɣ – fit in next step

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• S. Zenz - Higgs Seminar

6 February 2019

Signal extraction examples

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• S. Zenz - Higgs Seminar

6 February 2019

Signal extraction examples

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• S. Zenz - Higgs Seminar

6 February 2019

Beyond Discovery

• 2012 discovery: fit of all

production and decay modes

• Now: clear peak from

naive addition of events, just in ɣɣ

• Better still, we can

measure Higgs boson properties and search for rare production modes!

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• S. Zenz - Higgs Seminar

6 February 2019

Outline

• Why the Higgs boson?
• The Large Hadron Collider and Compact Muon Solenoid
• Higgs Properties → Analysis Strategy
• Production and decay modes
• Overview of H → ɣɣ (as an example)
• Where we are: what sort of Higgs Boson is it?
• Production and decay
• Differential measurements
• Where we’re going: the High Luminosity LHC (2026 and beyond)
• Analysis projections and measurements
• Higgs trilinear couplings
• How to get there, and what can we learn along the way?
• Measurements for Run 2 (2015-18) and Run 3 (2021-23)
• Stepping stones toward the HL-LHC

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• S. Zenz - Higgs Seminar

6 February 2019

H → ɣɣ Run 2 Results (so far)

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• S. Zenz - Higgs Seminar

6 February 2019

Fiducial and differential

• With simplified resolution classification, we can also bin H →ɣɣ

events in event shape variables

• Further test of SM predictions

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CMS-PAS-HIG-16-020

JHEP01(2019)183

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• S. Zenz - Higgs Seminar

6 February 2019

SM: The Whole Picture

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arXiv:1809.10733

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• S. Zenz - Higgs Seminar

6 February 2019

By Production and Decay

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• S. Zenz - Higgs Seminar

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Benchmark Model Fits

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• S. Zenz - Higgs Seminar

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ATLAS-CMS Run 1 Combination

• For the word’s best Higgs

measurements, use all available data from the LHC!

• Which mass uncertainty is

not like the others?

45

• J. High Energy Phys. 08 (2016) 045
• Phys. Rev. Lett. 114 (2015) 191803

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• S. Zenz - Higgs Seminar

6 February 2019

Outline

• Why the Higgs boson?
• The Large Hadron Collider and Compact Muon Solenoid
• Higgs Properties → Analysis Strategy
• Production and decay modes
• Overview of H → ɣɣ (as an example)
• Where we are: what sort of Higgs Boson is it?
• Production and decay
• Differential measurements
• Where we’re going: the High Luminosity LHC (2026 and beyond)
• Analysis projections and measurements
• Higgs trilinear couplings
• How to get there, and what can we learn along the way?
• Measurements for Run 2 (2015-18) and Run 3 (2021-23)
• Stepping stones toward the HL-LHC

46

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• S. Zenz - Higgs Seminar

6 February 2019

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• High luminosity LHC will collect up to 3000 fb-1starting in 2026
• Critical challenge: maintaining performance with 140-200 pileup

The HL-LHC

High pileup run: 78 reconstructed vertices

CERN-LPCC-2018-04

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• S. Zenz - Higgs Seminar

6 February 2019

H → ɣɣ and Differential Measurements

• We can do very precise measurements
• But why not…

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• S. Zenz - Higgs Seminar

6 February 2019

HH → bbɣɣ

• What do we learn from the notably

different signal-to-background ratio?

49

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• S. Zenz - Higgs Seminar

6 February 2019

Di-Higgs Combined

50

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• S. Zenz - Higgs Seminar

6 February 2019

Higgs Trilinear Coupling

• Non-SM trilinear coupling also changes single Higgs cross

sections, including changing differential distributions

51

CMS-PAS-FTR-18-020

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• S. Zenz - Higgs Seminar

6 February 2019

Higgs Trilinear Coupling

• Non-SM trilinear coupling also changes single Higgs cross

sections, including changing differential distributions

52

CMS-PAS-FTR-18-020

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• S. Zenz - Higgs Seminar

6 February 2019

Higgs Trilinear Coupling

• Non-SM trilinear coupling also changes single Higgs cross

sections, including changing differential distributions

53

• What if we combine these constraints with di-Higgs

searches, or even do a broader electroweak fit?

• How much data do we really need to tightly constrain the

Higgs trilinear coupling?

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• S. Zenz - Higgs Seminar

6 February 2019

Higgs Trilinear Coupling

• Non-SM trilinear coupling also changes single Higgs cross

sections, including changing differential distributions

54

• What if we combine these constraints with di-Higgs

searches, or even do a broader electroweak fit?

• How much data do we really need to tightly constrain the

Higgs trilinear coupling?

JHEP06(2018)146

LHC Higgs Run 1+2 Electroweak

• Should we be thinking bigger

and measuring a range of Effective Field Theory (EFT) parameters?

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• S. Zenz - Higgs Seminar

6 February 2019

Outline

• Why the Higgs boson?
• The Large Hadron Collider and Compact Muon Solenoid
• Higgs Properties → Analysis Strategy
• Production and decay modes
• Overview of H → ɣɣ (as an example)
• Where we are: what sort of Higgs Boson is it?
• Production and decay
• Differential measurements
• Where we’re going: the High Luminosity LHC (2026 and beyond)
• Analysis projections and measurements
• Higgs trilinear couplings
• How to get there, and what can we learn along the way?
• Measurements for Run 2 (2015-18) and Run 3 (2021-23)
• Stepping stones toward the HL-LHC

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• S. Zenz - Higgs Seminar

6 February 2019

New Properties to Measure in Run 2 and 3

• Run 2 SM Higgs analyses must be adapted for improved properties measurements
• Example idea being implemented: Simplified Higgs Template Cross Sections
• Extract μ-like cross section scalings in defined phase space(s)
• Reduce theory uncertainties
• More precisely targeted as more data become available, with first revision

already underway! (General plan: more pT bins)

• Other frameworks: expanded κ’s, Effective Field Theory parameters
• What’s the best approach for experiment to communicate with theory?

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Handbook of LHC Higgs Cross Sections: 4. Deciphering the Nature of the Higgs Sector, arXiv:1610.07922

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• S. Zenz - Higgs Seminar

6 February 2019

STXS Stage 1

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Region Purity / Category 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 Category

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

Hjj T

VBF loose, low p

Hjj T

VBF tight, low p

H j j T

VBF loose, high p

Hjj T

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

STXS Regions

ggH (0-jet) < 60 GeV)

H T

ggH (1-jet, p < 120 GeV)

H T

p ≤ ggH (1-jet, 60 < 200 GeV)

H T

p ≤ ggH (1-jet, 120 200 GeV) ≥

H T

ggH (1-jet, p < 60 GeV)

H T

2-jet, p ≥ ggH ( < 120 GeV)

H T

p ≤ 2-jet, 60 ≥ ggH ( < 200 GeV)

H T

p ≤ 2-jet, 120 ≥ ggH ( 200 GeV) ≥

H T

2-jet, p ≥ ggH ( ggH (VBF-like, 3-jet veto) ggH (VBF-like, 3-jet) Hqq (VBF-like, 3-jet veto) → qq Hqq (VBF-like, 3-jet) → qq Hqq (VH) → qq Hqq (rest) → qq 200 GeV) ≥

j T

Hqq (p → qq < 150 GeV)

V T

(p ν Hl → qq < 250 GeV)

V T

p ≤ (0-jet, 150 ν Hl → qq < 250 GeV)

V T

p ≤ 1-jet, 150 ≥ ( ν Hl → qq 250 GeV) ≥

V T

(p ν Hl → qq < 150 GeV)

V T

Hll (p → qq < 250 GeV)

V T

p ≤ Hll (0-jet, 150 → qq < 250 GeV)

V T

p ≤ 1-jet, 150 ≥ Hll ( → qq 250 GeV) ≥

V T

Hll (p → qq < 150 GeV)

V T

Hll (p → gg 150 GeV) ≥

V T

Hll (0-jet, p → gg 150 GeV) ≥

V T

1-jet, p ≥ Hll ( → gg ttH tHq tHW bbH

ATLAS Simulation

GeV = 125.09

H

, m γ γ → H

• Phys. Rev. D 98 (2018) 052005

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• S. Zenz - Higgs Seminar

6 February 2019

Stepping Stones: STXS Bin Merging

• STXS bins as

initially defined are tough to measure!

• Limited

statistics

• Sometimes

hard to separate even in principle

58

Process Measurement region Particle-level stage-1 region ggH + gg → Z(→ qq)H 0-jet 0-jet 1-jet, pH

T < 60 GeV

1-jet, pH

T < 60 GeV

1-jet, 60 ≤ pH

T < 120 GeV

1-jet, 60 ≤ pH

T < 120 GeV

1-jet, 120 ≤ pH

T < 200 GeV

1-jet, 120 ≤ pH

T < 200 GeV

≥ 1-jet, pH

T > 200 GeV

1-jet, pH

T > 200 GeV

≥ 2-jet, pH

T > 200 GeV

≥ 2-jet, pH

T < 200 GeV or VBF-like

≥ 2-jet, pH

T < 60 GeV

≥ 2-jet, 60 ≤ pH

T < 120 GeV

≥ 2-jet, 120 ≤ pH

T < 200 GeV

VBF-like, pHjj

T

< 25 GeV VBF-like, pHjj

T

≥ 25 GeV qq0 → Hqq0 (VBF + V H) pj

T < 200 GeV

pj

T < 200 GeV, VBF-like, pHjj T

< 25 GeV pj

T < 200 GeV, VBF-like, pHjj T

≥ 25 GeV pj

T < 200 GeV, V H-like

pj

T < 200 GeV, Rest

pj

T > 200 GeV

pj

T > 200 GeV

V H (leptonic decays) V H leptonic q¯ q → ZH, pZ

T < 150 GeV

q¯ q → ZH, 150 < pZ

T < 250 GeV, 0-jet

q¯ q → ZH, 150 < pZ

T < 250 GeV, ≥ 1-jet

q¯ q → ZH, pZ

T > 250 GeV

q¯ q → WH, pW

T < 150 GeV

q¯ q → WH, 150 < pW

T < 250 GeV, 0-jet

q¯ q → WH, 150 < pW

T < 250 GeV, ≥ 1-jet

q¯ q → WH, pW

T > 250 GeV

gg → ZH, pZ

T < 150 GeV

gg → ZH, pZ

T > 150 GeV, 0-jet

gg → ZH, pZ

T > 150 GeV, ≥ 1-jet

Top-associated production top t¯ tH W-associated tH (tHW) t-channel tH (tHq) b¯ bH merged w/ ggH b¯ bH

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• S. Zenz - Higgs Seminar

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Stepping Stones: Double-differential Distributions

• With HL-LHC data, we can

provide decent measurements of double-differential distributions

• First examples arriving
• Future binning not mapped out

(yet)… what will the impact really be?

• Goal at each step is to give the

finest binning that has a meaningfully small statistical and expert

59

T

p / d

fid

d

3

10

2

10

1

10 1 10

ATLAS

• 1

= 13 TeV, 36.1 fb s , H Data, tot. unc.

• Syst. unc.

XH default MC + H gg bbH + ttH + VH = VBF+ XH

[GeV]

T

p

0-15 15-30 30-75 75-350 0-40 40-60 60-100 100-350 0-100 100-200 200-350 0-200 200-350

XH Ratio to default MC + 2 4

= 0

jets

N = 1

jets

N = 2

jets

N 3

jets

N

T

p / d

fid

d

3

10

2

10

1

10 1 10

ATLAS

• 1

= 13 TeV, 36.1 fb s , H Data, tot. unc.

• Syst. unc.

XH default MC + H gg bbH + ttH + VH = VBF+ XH

[GeV]

T

p

0-30 30-120 120-350 0-30 30-120 120-350

XH Ratio to default MC + 1 2

*)| < 0.5 |cos( 0.0 *)| < 1.0 |cos( 0.5

• Phys. Rev. D 98 (2018) 052005

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Conclusions

60

• Many ways to use make precision measurements of SM-

like Higgs properties and potential deviations

• Cross sections (differential, STXS, …)
• Fits to parameters that modify the SM (κ’s, EFT’s)
• Related approaches would take several more seminars
• Direct searches for BSM Higgs bosons
• SM Higgs bosons in BSM events
• Fits for parameters in specific BSM models (e.g.

2HDM)

• More fundamental work: detector upgrades,

reconstruction, and reducing systematics

• Which ideas will bear fruit, and when?
• All we can do is try, and find out!
• My prediction: whatever precision we need, the right

combination of state-of-the-art techniques will get us there before our current projections suggest

• Higgs looks like the Standard Model, but stay tuned...