STANDARD MODEL. Precision Electroweak data?? Higgs coupling blows up!! Higgs potential collapses...

STANDARD MODEL

Precision

Electroweak

data??

Higgs

coupling

blows up!!

Higgs

potential

collapses

Higgs coupling less

than in Standard Model

viXra Blogger’s Combination

of Dec.13th Data

There must be New Physics

Beyond the Standard Model

Theorists getting Cold Feet

• Composite Higgs model?conflicts with precision electroweak data

• Interpretation of EW data?consistency of measurements? Discard some?

• Higgs + higher-dimensional operators?corridors to higher Higgs masses?

• Little Higgs models?extra `Top’, gauge bosons, `Higgses’

• Higgsless models?strong WW scattering, extra D?

Heretical Interpretation of EW Data

Do all the data

tell the same story?

e.g., AL vs AH

What attitude towards LEP, NuTeV?

What most

of us think

Chanowitz

Spread looks natural: no significant disagreement

Estimates of mH from different Measurements

Higgs + Higher-Order Operators

Precision EW data suggest they are small: why?

But conspiracies

are possible: mH

could be large,

even if believe

EW data …?

Do not discard possibility of heavy Higgs

Corridor to

heavy Higgs?

Barbieri, Strumia

Elementary Higgs or Composite?

• Higgs field:

<0|H|0> ≠ 0• Quantum loop problems

• Fermion-antifermion condensate

• Just like QCD, BCS superconductivity

• Top-antitop condensate? needed mt > 200 GeV

New technicolour force?-Heavy scalar resonance?-Inconsistent with precision electroweak data?

Cut-off Λ ~ 1 TeV with

Supersymmetry?

Cutoff

Λ = 10 TeV

Comparison between Weakly- and Strongly-coupled Models

Interpolating Models

• Combination of Higgs boson and vector ρ

• Two main parameters: mρ and coupling gρ

• Equivalently ratio weak/strong scale:

gρ / mρ

Grojean, Giudice, Pomarol, Rattazzi

Intermediate Models

Effects on Higgs Decays

• Dependences on ξ of Higgs branching ratios

• Standard Model recovered in limit ξ0

Grojean, Giudice, Pomarol, Rattazzi

Higgs as a Pseudo-Goldstone

Boson

Loop cancellation mechanism

SupersymmetryLittle Higgs

‘Little Higgs’ models

(breakdown of larger symmetry)

Little Higgs Models

• Embed SM in larger gauge group• Higgs as pseudo-Goldstone boson• Cancel top loop

with new heavy T quark

• New gauge bosons, Higgses• Higgs light, other new

physics heavyNot as complete as susy: more physics > 10 TeV

MT < 2 TeV (mh / 200 GeV)2

MW’ < 6 TeV (mh / 200 GeV)2

MH++ < 10 TeV

Examples of Higgs as Pseudo-Goldstone Boson

• Parameterization of effective Lagrangian:

• Examples:

• To be measured!

What if the Higgs is not quite a Higgs?

• Tree-level Higgs couplings ~ masses– Coefficient ~ 1/v

• Couplings ~ dilaton of scale invariance• Broken by Higgs mass term –μ2, anomalies

– Cannot remove μ2 (Coleman-Weinberg)– Anomalies give couplings to γγ, gg

• Generalize to pseudo-dilaton of new (nearly) conformal strongly-interacting sector

• Pseudo-Goldstone boson of scale symmetry

A Phenomenological Profile of a Pseudo-Dilaton

• Universal suppression of couplings to Standard Model particles: a = c = v/V

• Effective potential:• Self-couplings:

• Γ(gg) may be enhanced• Γ(γγ) may be suppressed

Compilation

of constraints

Campbell, JE, Olive: arXiv:1111.4495

Updated

with Dec. 11

constraints

Pseudo-baryons as dark matter?

General Analysis of ‘Less Higgs’ Models

• Parameterization of effective Lagrangian:

• Fitsa ≠ c

Azatov, Contino, Galloway: arXiv:1202.3415 Espinosa, Grojean, Muhlleitner, Trott: arXiv:1202.3697

General Analysis of ‘Less Higgs’ Models

• Separate fits to CMS and ATLAS data:

Azatov, Contino, Galloway: arXiv:1202.3415

Sum Rule for More or Less Higgs Models

• What if Higgs-V-V couplings differ from SM?

• Unitarity imposes sum rule on scattering in different isospin channels:

• If Higgs coupling > Standard Model (a2 > 1), must have non-zero scattering with I = 2

Fialkowski, Rychkov, Urban: arXiv:1202.1532

Higgsless Models?

• Four-dimensional versions:

Strong WW scattering @ TeV, incompatible with precision data?

• Break EW symmetry by boundary conditions in extra dimension:

delay strong WW scattering to ~ 10 TeV?

Kaluza-Klein modes: mKK > 300 GeV?

compatibility with precision data?• Warped extra dimension + brane kinetic terms?

Lightest KK mode @ few 00 GeV, strong WW @ 6-7 TeV

Particle Spectrum in Simplest Model with Extra Dimensions

Lowest-lying states have flat wave functions (n = 0)

Excitations (Kaluza-Klein) have nodes (n > 0):

Mass ~ n/R (R = radius of circle)

‘Fold’ Circle: Orbifold

• Identify two halves of circle: up to a minus sign

• ‘Even’ particles include massless: odd ones all massive• A way to give masses to particles that are asymmetric

Mechanism to break Gauge Symmetry

• Identify two halves up to a group transformation U

• Unbroken part of gauge group commutes with U• Masses for asymmetric particles:

– e.g., SU(2) × U(1) U(1)

Search for Vector Resonance in Higgsless Model

Vector resonance structure in WZ scattering

Simulation of resonance structure in mWZ @ LHC