getting a discussion going tilman plehn aspen, january 2015plehn/... · lagrangian rates...
Post on 18-Aug-2020
0 Views
Preview:
TRANSCRIPT
Higgs Precision
Tilman Plehn
Lagrangian
Rates
Distributions
Lepton Collider
Effective Theory
Self-CouplingPrecision Higgs Physics
Getting a Discussion Going
Tilman Plehn
Universitat Heidelberg
Aspen, January 2015
Higgs Precision
Tilman Plehn
Lagrangian
Rates
Distributions
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
Lagrangian
Rates
Distributions
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]
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
Lagrangian
Rates
Distributions
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]
2. What are the coupling values?
– only sensible question after fixing operator basis
– Standard Model operators vs anomalous couplings
– effective theory to exploit distributions?
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
Lagrangian
Rates
Distributions
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]
2. What are the coupling values?
– only sensible question after fixing operator basis
– Standard Model operators vs anomalous couplings
– effective theory to exploit distributions?
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
Lagrangian
Rates
Distributions
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
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
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
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
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
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
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
Rates
Distributions
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
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
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
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
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
– 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
Distributions
Lepton Collider
Effective Theory
Self-Coupling
Couplings from LHC distributions 2
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
Couplings from LHC distributions 2
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
Measuring ∆t,g from p4` distributions [Buschmann, Goncalves, Kuttimalai, Schonherr, Krauss, TP]
– easier to simulate: MCFM
sensitive region m4` > 500 GeV
systematic/theory errors potentially bad
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
Couplings from LHC distributions 2
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
Measuring ∆t,g from p4` distributions [Buschmann, Goncalves, Kuttimalai, Schonherr, Krauss, TP]
– easier to simulate: MCFM
sensitive region m4` > 500 GeV
systematic/theory errors potentially bad
– most optimistic: statistics only
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
⇒ probably statistics limitednot great compared to SFitter extrapolation...
Higgs Precision
Tilman Plehn
Lagrangian
Rates
Distributions
Lepton Collider
Effective Theory
Self-Coupling
Couplings from LHC distributions 2
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
Measuring ∆t,g from p4` distributions [Buschmann, Goncalves, Kuttimalai, Schonherr, Krauss, TP]
– easier to simulate: MCFM
sensitive region m4` > 500 GeV
systematic/theory errors potentially bad
– most optimistic: statistics only
H → eeµµ analysis
2D likelihood study of cos θe,m4`
⇒ ∆t = −0.3 to 95% CL with 1700 fb−1
⇒ probably statistics limitednot great compared to SFitter extrapolation...
-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
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...
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
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...
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
top related