getting a discussion going tilman plehn aspen, january 2015plehn/... · lagrangian rates...

Higgs Precision

Tilman Plehn

Lagrangian

Rates

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Lepton Collider

Effective Theory

Self-CouplingPrecision Higgs Physics

Getting a Discussion Going

Tilman Plehn

Universitat Heidelberg

Aspen, January 2015

Higgs Precision

Tilman Plehn

Lagrangian

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Lepton Collider

Effective Theory

Self-Coupling

In field theory language

1. What are the ‘Higgs’ Operators

– CP-even spin-0 scalar pretty much clearspin-1 vector unlikelyspin-2 graviton unexpected

– ask flavor colleagues [Cabibbo–Maksymowicz–Dell’Aquila–Nelson angles]

Higgs Precision

Tilman Plehn

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Lepton Collider

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2. What are the coupling values?

– only sensible question after fixing operator basis

– Standard Model operators vs anomalous couplings

– effective theory to exploit distributions?

Higgs Precision

Tilman Plehn

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3. What does all this tell us?

– strongly interacting models?

– weakly interacting two-Higgs-doublet models?

– TeV-scale new physics?

– vacuum stability?

Higgs Precision

Tilman Plehn

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3. Can this contribute to the case for future colliders?

– precision Higgs measurements?

– direct searches for extended Higgs sectors?

– or maybe go for ‘dark matter factory’?

Higgs Precision

Tilman Plehn

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Lepton Collider

Effective Theory

Self-Coupling

Couplings from LHC rates

Standard Model operators [SFitter: Klute, Lafaye, TP, Rauch, Zerwas]

– most inclusive information: signal strengths

– assume: narrow CP-even scalarStandard Model operators

– couplings from production & decay rates

t W,Z

b,tW,Z

gg → Hqq → qqHgg → t tHqq′ → VH

←→ gHXX = gSMHXX (1 + ∆X ) ←→

H → ZZH → WWH → bbH → τ+τ−

H → γγ

Higgs Precision

Tilman Plehn

Lagrangian

Rates

Distributions

Lepton Collider

Effective Theory

Self-Coupling






t W,Z

b,tW,Z


←→ gHXX = gSMHXX (1 + ∆X ) ←→


H → γγ

After Run 1 [Lopez-Val, TP, Rauch]

– SFitter: focus on theory uncertainties

6D, SM-like [secondary solutions possible]

ratios and correlations fully included

-0.5

0

0.5

1

∆H

∆V

∆f

∆W

∆Z

∆t

∆b

∆τ

∆γ

∆Z/W

∆τ/b

∆b/W

gx = gxSM

(1+∆x)

L=4.6-5.1(7 TeV)+12-21(8 TeV) fb-1

, 68% CL: ATLAS + CMS

SM exp.

data

data (+∆γ)

Moriond 2013

Higgs Precision

Tilman Plehn

Lagrangian

Rates

Distributions

Lepton Collider

Effective Theory

Self-Coupling






t W,Z

b,tW,Z


←→ gHXX = gSMHXX (1 + ∆X ) ←→


H → γγ

After Run 1 [Lopez-Val, TP, Rauch]

– SFitter: focus on theory uncertainties

6D, SM-like [secondary solutions possible]

ratios and correlations fully included

– HiggsSignals: focus on public tool

7D including invisible decay

– ATLAS and CMS similar

⇒ couplings and ratios very successful

0.0 0.1 0.2 0.3 0.4 0.5 0.6

BR(H → inv.)1σ

2σ

κV1σ

2σ

κu1σ

2σ

κd1σ

2σ

κℓ1σ

2σ

κg1σ

2σ

0 0.5 1 1.5 2 2.5

κγ1σ

2σ

Higgs Precision

Tilman Plehn

Lagrangian

Rates

Distributions

Lepton Collider

Effective Theory

Self-Coupling






t W,Z

b,tW,Z


←→ gHXX = gSMHXX (1 + ∆X ) ←→


H → γγ

LHC challenges: invivible decays [Bernaciak, TP, Schichtel, Tattersall]

– WBF best channel at LHC [Eboli & Zeppenfeld]

– baseline cuts: jet veto plus ∆φjjmultivariate: 2-jet, 3-jet sample

– reach BRinv ∼ 7% for 3000 fb−1

– further improvement to 3%from QCD jets to 10 GeV...

⇒ QCD the limiting factor

0.000 0.005 0.010 0.015 0.020 0.025 0.030εs

0.15

0.1

0.05

0

ε b[1

0−5]

Baseline

Baseline + C.J.V.

Baseline + C.J.V. + ∆Φ

20 GeV Jets

2-Jet sample BDT3-Jet sample BDTCombined BDTBox Cuts

Higgs Precision

Tilman Plehn

Lagrangian

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Lepton Collider

Effective Theory

Self-Coupling

Couplings from LHC distributions 1

Top–Higgs–gluon Lagrangian [Ellis, Hinchliffe, Soldate, v d Bij; Baur & Glover]

– test ggH vertex structure [to keep production rate]

L = LSM +

(∆t gggH + ∆g

αs

12π

)Hv

GµνGµν

– high-pT logarithms [Banfi etal; Azatov etal; Grojean etal; Buschmann etal]

|MHj(j)|2 ∼

m4t

p4T

log4 p2T

m2t

Higgs Precision

Tilman Plehn

Lagrangian

Rates

Distributions

Lepton Collider

Effective Theory

Self-Coupling




L = LSM +

(∆t gggH + ∆g

αs

12π

)Hv

GµνGµν


|MHj(j)|2 ∼

m4t

p4T

log4 p2T

m2t

Measuring ∆t,g from pT ,H distributions [Buschmann, Goncalves, Kuttimalai, Schonherr, Krauss, TP]

– simulation: SHERPA NLO-merged [it’s public]

sensitive region pT ,H > 250 GeV

systematic/theory errors potentially bad

0 100 200 300 400 500 600

-410

-310

-210

-110

1 tmH+0j NLO

tmH+1j NLO

tmH+2j LO

tmH+jets NLO

∞ →tmH+jets NLO

GeVfb

T,Hdp

σd

[GeV]T,H

p0 100 200 300 400 500 600

0.2

0.4

0.6

0.8

1

1.2

∞→tm(N)LO

tm(N)LO

Higgs Precision

Tilman Plehn

Lagrangian

Rates

Distributions

Lepton Collider

Effective Theory

Self-Coupling




L = LSM +

(∆t gggH + ∆g

αs

12π

)Hv

GµνGµν


|MHj(j)|2 ∼

m4t

p4T

log4 p2T

m2t

Measuring ∆t,g from pT ,H distributions [Buschmann, Goncalves, Kuttimalai, Schonherr, Krauss, TP]

– simulation: SHERPA NLO-merged [it’s public]

sensitive region pT ,H > 250 GeV


– most optimistic: statistics only

H → WW analysis

2D likelihood study of njets, pT ,H

⇒ ∆t = −0.3 to 95% CL with 700 fb−1

]-1L [fb200 400 600 800 1000 1200 1400 1600 1800 2000

sC

L

0.001

0.01

0.1

T,H, p

jetsExclusion plot based on n

95% exclusion

σ1 σ2

expected 95% CL

=(0.7,0.3)tgk

WW→H

Higgs Precision

Tilman Plehn

Lagrangian

Rates

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Lepton Collider

Effective Theory

Self-Coupling


Not-model-independent width measurements [Kauer & Passarino; Caola & Melnikov; Ellis & Williams]

– peak cross section vs off-shell interference in H → ZZ

σpeak ∼g2

g g2Z

(s − m2)2 + m2Γ2=

g2g g2

Z

m2Γ2σoff(gggZ )∼ σcont −

Aint gggZ

s − m2+

AH g2g g2

Z

(s − m2)2

– top–Higgs–gluon Lagrangian again [m4` � mt > mH ]

Mgg→ZZ ∼ ±m2

t

m2Z

log2 m24`

m2t

Higgs Precision

Tilman Plehn

Lagrangian

Rates

Distributions

Lepton Collider

Effective Theory

Self-Coupling




σpeak ∼g2

g g2Z

(s − m2)2 + m2Γ2=

g2g g2

Z


Aint gggZ

s − m2+

AH g2g g2

Z

(s − m2)2


Mgg→ZZ ∼ ±m2

t

m2Z

log2 m24`

m2t

Measuring ∆t,g from p4` distributions [Buschmann, Goncalves, Kuttimalai, Schonherr, Krauss, TP]

– easier to simulate: MCFM

sensitive region m4` > 500 GeV


100 200 300 400 500 600 700 800 900 1000

-410

-310

-210

-110qq

gg

=(0,0)t,gκ

=(1,0)t,gκ

=(0,1)t,gκ

GeVfb

4ldm

σd ZZ→pp

SMHΓ=HΓ

[GeV]4lm100 200 300 400 500 600 700 800 900 10000

1

2

3

=(0,1)t,gκLO=(1,0)t,gκLO

⇒ probably statistics limitednot great compared to SFitter extrapolation...

Higgs Precision

Tilman Plehn

Lagrangian

Rates

Distributions

Lepton Collider

Effective Theory

Self-Coupling




σpeak ∼g2

g g2Z

(s − m2)2 + m2Γ2=

g2g g2

Z


Aint gggZ

s − m2+

AH g2g g2

Z

(s − m2)2


Mgg→ZZ ∼ ±m2

t

m2Z

log2 m24`

m2t






H → eeµµ analysis

2D likelihood study of cos θe,m4`

⇒ ∆t = −0.3 to 95% CL with 1700 fb−1

]-1L [fb500 1000 1500 2000 2500 3000

sC

L

0.001

0.01

0.1

4l and meθExclusion plot based on cos

95% exclusion

σ1 σ2

expected 95% CL

=(0.7,0.3)tgk

ZZ→gg


Higgs Precision

Tilman Plehn

Lagrangian

Rates

Distributions

Lepton Collider

Effective Theory

Self-Coupling




σpeak ∼g2

g g2Z

(s − m2)2 + m2Γ2=

g2g g2

Z


Aint gggZ

s − m2+

AH g2g g2

Z

(s − m2)2


Mgg→ZZ ∼ ±m2

t

m2Z

log2 m24`

m2t






H → eeµµ analysis

2D likelihood study of cos θe,m4`

⇒ ∆t = −0.3 to 95% CL with 1700 fb−1


-0.6

-0.4

-0.2

0

0.2

0.4

0.6

∆W

∆Z

∆t

∆b

∆τ

∆γ

∆g

∆Z/W

∆τ/b

∆b/W

gx = gxSM

(1+∆x)

68% CL: 100 fb-1

, 14 TeV LHC

ttH only H->WW

ttH only H->γγ

ttH only H->bb (old)

ttH only H->bb (subjet)

Higgs Precision

Tilman Plehn

Lagrangian

Rates

Distributions

Lepton Collider

Effective Theory

Self-Coupling

Couplings from e+e− rates

Obviously Higgs precision machine

– ZH production requiring 250 GeVrecoil measurement better than direct Higgs production

– clean detector environment

– α� αs and few nasty logs

⇒ sub-percent precision realistic

Precision rate measurements [Klute, Lafaye, TP, Rauch, Zerwas]

– again assume SM-like Higgs

– recoil measurement of σZH to check

– theory uncertainties on BRs critical

– ∆c possible∆t challenging∆g and ∆γ mostly from LHC

⇒ e+e− Higgs factory a clear Euro-case

-0.15

-0.1

-0.05

0

0.05

0.1

0.15

0.2

∆H

∆W

∆Z

∆t

∆c

∆b

∆τ

∆γ

∆g

gx = gxSM

(1+∆x)

68% CL

HL-LC, 3000 fb-1

250 GeV TLEP, 4 exp. × 2.5 ab-1

Higgs Precision

Tilman Plehn

Lagrangian

Rates

Distributions

Lepton Collider

Effective Theory

Self-Coupling

Effective theory

Beyond modified coupings

– Higgs couplings Lagrangian not complete

HAµνAµν includedHZµνZµν not included [numerically relevant?]

– consistent basis from EFT [all D6 operators, Buchmuller & Wyler, Hagiwara & Zeppenfeld]

– added benefit from ∂/Λ terms [pT shape in VH production]

– consistency check from convergence [Azatov, Grojean, Paul, Salvioni; Dawson, Lewis, Zeng]

– trustworthy range of distributions key issue...

Higgs Precision

Tilman Plehn

Lagrangian

Rates

Distributions

Lepton Collider

Effective Theory

Self-Coupling

Effective theory








Light Higgs as a Goldstone boson [Contino, Giudice, Grojean, Pomarol, Rattazzi, Galloway,...]

– light state ad-hoc-protected by Goldstone’s theorem [Georgi & Kaplan]

– interesting if v � f < 4πf ∼ mρ [little Higgs v ∼ g2 f/(2π)]

dσ

(1 +

g2v2

f 2

)∼ dσ

(1 +

16π2g2v2

m2ρ

)?∼ dσ (1± 10%)

– specific D6 operator basis

– phenomenology dominated by (φ†φ)

⇒ EFT useful for strong interactions

Higgs Precision

Tilman Plehn

Lagrangian

Rates

Distributions

Lepton Collider

Effective Theory

Self-Coupling

Effective theory








Anomalous Higgs couplings [Corbett, Eboli, Gonzales-Fraile, Gonzales-Garcia]

– complete gauge-invariant Lagrangian with Higgs doublet– additional higher-dimensional couplings

Leff =−αsv8π

fgΛ2

(φ†φ)GµνGµν +fWW

Λ2φ†WµνWµν

φ

+fWΛ2

(Dµφ)†Wµν(Dνφ) +fBΛ2

(Dµφ)†Bµν(Dνφ) +fWWW

Λ2Tr(WµνWνρWµ

ρ )

+fbΛ2

(φ†φ)(Q3φdR,3) +fτΛ2

(φ†φ)(L3φeR,3)

⇒ analyses only just starting

Higgs Precision

Tilman Plehn

Lagrangian

Rates

Distributions

Lepton Collider

Effective Theory

Self-Coupling

Left for the pp Nimatron

Notorious: Higgs self-coupling

– call it Higgs pair production: strong interactions and resonances [Grober, Muhlleitner]

– marginal reach at HL-LHC [experimental simulations missing]

– equally hard at e+e− machines

Better at 100 TeV? [Barr, Dolan, Englert, Ferreira, Spannowky]

– easy channel HH → (bb)(γγ) [Baur, Rainwater, TP]

– useful distributions mHH and pT ,H [not used]

– 95% CL reach λ = λSM ± 40%

system [GeV] 2

a + 1a + 2 + b1 Mass of the b

300 400 500 600 700 800 900 1000 1100

Even

ts

-110

1

10

210

310

410

510 aabb ajbbaajj aajbajbj aattjjbb = 0h HH, × 410

SMh = h HH, × 410 SMh = 2 h HH, × 410

Higgs Precision

Tilman Plehn

Lagrangian

Rates

Distributions

Lepton Collider

Effective Theory

Self-Coupling

Left for the pp Nimatron

Notorious: Higgs self-coupling

– call it Higgs pair production: strong interactions and resonances [Grober, Muhlleitner]

– marginal reach at HL-LHC [experimental simulations missing]

– equally hard at e+e− machines

Better at 100 TeV? [Barr, Dolan, Englert, Ferreira, Spannowky]

– easy channel HH → (bb)(γγ) [Baur, Rainwater, TP]

– useful distributions mHH and pT ,H [not used]

– 95% CL reach λ = λSM ± 40%

system [GeV] 2

a + 1a + 2 + b1 Mass of the b

300 400 500 600 700 800 900 1000 1100

Even

ts

-110

1

10

210

310

410

510 aabb ajbbaajj aajbajbj aattjjbb = 0h HH, × 410

SMh = h HH, × 410 SMh = 2 h HH, × 410

Top Yukawa at 100 TeV? [TP, Schell; update of TP, Salam, Spannowsky]

– difficult analysis at LHC

– boosted tops/Higgs to solve combinatorics

– background from side band

– statistically ∆σttH/σttH ∼ 2%

0 50 100 150 200 2500

0.005

0.01

0.015

0.02

[GeV]rec

m

GeV

pb

recdm

σd

2 b-tags, 3 pairings

Htt

bbtt

Higgs Precision

Tilman Plehn

Lagrangian

Rates

Distributions

Lepton Collider

Effective Theory

Self-Coupling

Higgs precision goals

Challenges

– hadron colliders systematics/theory limited

– e+e− Higgs factory justifiable

– 100 TeV not really Higgs-motivated......but maybe helpful for λH and yt

– no colorful Higgs advertizing figures, sorry...

σ(χ1±χ20) = ●<10-3 || ●10-2 || ●10-1 || ●1 || ●10 || ●>102 pb

-4 -3 -2 -1 0 1 2 3 4

m@TeVD01234

M1@Te

VD

0

1

2

3

4M2@Te

VD

tan β=10

Much of this work was funded by the BMBF Theorie-Verbund which is ideal for relevant LHC work

Higgs Precision

Tilman Plehn

Lagrangian

Rates

Distributions

Lepton Collider

Effective Theory

Self-Coupling

getting a discussion going tilman plehn aspen, january 2015plehn/... · lagrangian rates...

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