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H i i g ggs s ph physi ysi cs cs at t th the e LH C Mar arc c Riembau bau Universit de Genve Interpretjng the LHC Run 2 data and beyond May 2019 SMs own demise: Muon decay signals the existence of new physics

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H i g i ggs ph s physi cs ysi cs at t th the e LH C

Mar arc c Riembau bau Université de Genève

Interpretjng the LHC Run 2 data and beyond

May 2019

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SM’s own demise:

Muon decay signals the existence of new physics Inconsistency of W scattering implies the need for a unitarization mechanism Higgs mass cannot be computed but estimated: The estimation tells you that There must be more stufg at the EW scale

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E E E g E

strong sector elementary sector

E

Nature’s options

Technicolor: a heavier copy

  • f QCD can induce EWSB

Higgs as a Nambu-Goldstone boson EWBS is generated radiativelly Supersymmetry: no quadratic divergences Dark matter GUT & gravity

arXiv: 9709356

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Introductjon The two major discoveries of the LHC: h

  • A light scalar apparently compatjble

with the SM Higgs boson

  • An apparent mass gap above

the EW scale

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Introductjon

SM Higgs is not an explanation of EWSB, just a parametrization. Why sacrifjce so much for simplicity? Why is the EW scale so special?

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Introductjon LHC in the LEP tunnel Vol. 1, 1984

SM Higgs is not an explanation of EWSB, just a parametrization. Why sacrifjce so much for simplicity? Why is the EW scale so special?

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Introductjon The two major discoveries of the LHC:

  • A light scalar apparently compatjble

with the SM Higgs boson

  • An apparent mass gap above

the EW scale

BSM

h

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8

Introductjon Both discoverries were suggested by precision measurements

  • A light scalar apparently compatjble

with the SM Higgs boson

  • An apparent mass gap above

the EW scale

BSM

h

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Introductjon

For example, for composite Higgs models, LEP constraints already told us that G i udi ce ce, G r

  • j

e j ean, Pom ar

  • l
  • l

, Rattazzi , ‘ ‘ 07

BSM

h

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Introductjon

Can we continue this program at LHC? Yes, «energy helps accuracy» Fari na, Pani co co, Pappadop

  • pul
  • ,

Ruderm an, Torr e, W ul zer ‘ 16

h

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An example in diboson

In the unitary gauge, and in the SM,

  • Each of the contributions

separately grows with energy

  • In the SM, the couplings

are such that there is no pathological growth of the amplitude

  • This also means that non-SM couplings induce deviations that get

amplifjed at high energies An explicit example in diboson: In the unitary gauge, and in the SM,

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An example in diboson

In the unitary gauge, and in the SM,

  • Each of the contributions

separately grows with energy

  • In the SM, the couplings

are such that there is no pathological growth of the amplitude

  • This also means that non-SM couplings induce deviations that get

amplifjed at high energies An explicit example in diboson: In the unitary gauge, and in the SM,

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An example in diboson

Constant shift of cross section Limited by systematics Efgects enhanced at high energies Limited by statistics

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LEP, Z pole measurements HL-LHC, diboson

G r

  • j

e j ean, M ontul l , M R, ‘ 1 ‘ 18

An example in diboson

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15 From an EFT perspective, it is clear in the Feynman gauge, where the Goldstone bosons are manifest

An example in diboson

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Higgs with Higgs

But now we have a new guy in the spectrum. The Higgs probes a sector untested before: G upta, Pom ar

  • l

, Ri va, ‘ 1 ‘ 14 M asso, ‘ 1 ‘ 14 Each SM input defjnes a direction only probed by Higgs physics, they look like

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17 The directions defjned by these Higgs operators are constrained by measuring the on-shell Higgs production rates and its branching ratios

Higgs with Higgs

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18 H L-LH C pr

  • j

e j ect cti

  • ns:

On-shell Higgs coupling (HC) measurements will be saturated by systematics: > will not benefjt from collecting more luminosity > inclusive rates will not benefjt from going to higher collider energies

x3 x4 x5 x7 x4

x10 Higgs with Higgs

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19 H L-LH C pr

  • j

e j ect cti

  • ns:

x3 x4 x5 x7 x4

x10

This talk is about a program to measure Higgs properties in a way that

  • It is limited by statistics, i.e., it does benefjt from larger luminosities
  • It benefjts from going at higher collider energies, crucial for

HE-LHC, CLIC, FCC/SppC On-shell Higgs coupling (HC) measurements will be saturated by systematics: > will not benefjt from collecting more luminosity > inclusive rates will not benefjt from going to higher collider energies

Higgs with Higgs

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Higgs without Higgs

there must be some process where an anomalous Yukawa induces a pathological growth in energy../ Tha same logic we applied to diboson can be applied to Higgs couplings:

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Higgs without Higgs

Tha same logic we applied to diboson can be applied to Higgs couplings: unanchor the Higgs from its vev

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This puts in correspondence Higgs operators with High Energy, multiboson processes with enhanced sensitivity

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Higgs self-coupling

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Higgs self-coupling ?

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Higgs self-coupling

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Higgs self-coupling HL-LHC @ 3 ab-1, 95% CL

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Higgs self-coupling HL-LHC @ 3 ab-1, 95% CL

7!

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Higgs self-coupling

A TL-PH YS -PU B-2019-009 Reinterpretation of single Higgs processes: Large fmat directions when other Higgs coupling deformations enter. Global fjt to difgerential observables needed

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Higgs self-coupling

Bi shar a, C on

  • nti

no, Roj

  • j
  • ,

‘ 1 ‘ 16 No growth with energy, not really competitive with gluon production Nonetheless, focus of the paper is not in the trilinear

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Higgs self-coupling

Transverse modes scale as 1/E and become an important background

but,

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Higgs self-coupling

VBF topology

Same sign leptons!

Signal enhanced only with a single power of energy, but extremelly attractive and clean process experimentally!

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Higgs self-coupling

  • 50-ish events in the SM
  • Irreducible background negligible
  • Background from ttjj with lepton misidentifjcation under control
  • Backgorund from fake leptons is potentially the dominant one.

We parametrize it with #back = B x #signal.

  • Rough cut-and-count analysis gives competitive results with double higgs production
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Higgs self-coupling

(In progress w/ experimental group in U. Geneve)

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Higgs self-coupling

Partonic COM @ 2 TeV:

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Higgs self-coupling

Partonic COM @ 2 TeV:

Similar sensitivity First process overwhelmed by transverse modes

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Longitudinal Transverse Boost

Direction of decay products correlated with vector pT and polarization

slide from Steven Schramm

Angle and energy of two last steps of anti-kT algorithm sensitive to vector polarization!

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Top Yukawa

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Top Yukawa

Many fjnal states, many decays../ just if we had something to simplify the analysis../

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Top Yukawa boosted top # events @ HL-LHC

Strategy: look for a single boosted top + forward jet, then just count leptons!

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Top Yukawa boosted top # events @ HL-LHC small background

Large background from ttjj, but manageable. Going to larger top pT’s possible

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Top Yukawa

Again, we parametrize background with B x signal Competitive with on-shell Higgs measurements >2 leptons only

Further improvements: background characterization, specially for hadronic, difgerential information, larger E^2, get rid of transverse polarizations

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H to gluons

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H to gluons

1/Energy

Production of longitudinal modes goes to zero at high energies (similar to send quarks mass to zero)

Should be possible to ‘sit’ at this maximum and dig out the longitudinals to improve constraints & be sensitive to linear terms only Contraints looking

  • nly at rates:

A m p l i t u d e G l

  • ver,

van der Bi j , j , 89 A zatov, v, G r

  • j
  • j

ean, Paul , S al vi vi

  • ni

, ‘ 1 ‘ 14

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Vector boson scatuering

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Vector boson scatuering

Usually, VBS is interpreted in terms of dimension 8 operators. But they recieve contributions from Higgs operators We project current analysis on W+W+, WZ, ZZ and Zγ A TLA S , 1705. 01966 e. g. g. , A TLA S , 1405. 6241 Other channels, W+W-, W+ , are left for future study. γ γγ VBS with VH fjnal state is not studied so far, but it might be comparably sensitive. Hardness of 2 2 characterized by scalar sum of vectors’ pT, we bin on it.

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Vector boson scatuering

  • Competitive for Z , not for

γ γγ

  • If VBS with W+fat jet, W+W- will also enter
  • VBF of VH to be studied
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Conclusions

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Conclusions

  • Characterization of Higgs is crucial
  • High energy Higgs probes competitive and complementary to HC measurements
  • Important for future high energy colliders, HE-LHC, CLIC, FCC/SppC
  • Endless oportunities for improvements:

Precise theoretical predictions Understanding of relevant kinematics Even more primitive: understanding of relevant processes Experimental control of systematics and backgrounds Understanding of longitudinal vs transverse gauge bosons BSM interpretation ...

  • Plenty of relevant physics yet to be explored