Non-standard Higgs Boson interactions and (inverse) implications for LHC

Daniel Phalen, Brooks Thomas, James Wells

Michigan/MCTP, April 2006

Measured Sensitivities to Higgs mass

EWWG, 2005

Observables Compatible with SM

Many observables computedat LEP, SLC, and Tevatronthat tell us about compatibility.

Higgs mass limit

Higgs boson mass upper limit(95% CL) from precision Electroweak is about 200 GeV.

Lower limit from lack ofdirect signal at LEP 2is about 115 GeV.

LEPEWWG

Compatibility of New Physics

It is reasonable to assume that new physics may have a light SM-like Higgs boson and extra stuff thatmostly decouples from Precision EW analysis.

Precision EW conspiracies are possible but wedo not consider that here.

Small Higgs pheno deviations

However, in most beyond the SM scenarios, The lightest Higgs is not exactly the SM Higgs.The deviations are nonzero but small.

How do we characterize these deviations inthe most model-independent fashion possible?

How are they to be measured?

SupersymmetryMass matrix of the CP-even scalars in {Hd,Hu} basis:

Mass matrix rotated to get mass eigenstates {h,H}

SUSY Higgs Couplings

Expansion about Small Deviations

Loinaz, JW

Loop decays and SUSY

Of course, we also know about SUSY particleContributions to higgs decays to photons and gluons

Top quarks, and squarksin the loop

Top quark, W, and SUSYsparticles in the loop

Extra Dimensions: Radion

Kinetic terms:

Interactions with massive fermions and bosons:

Interactions withgluons -- Tr(T) not equal to zero:

Small Higgs deviations

Small kinetic mixing between radion and Higgscreates an eigenstate that is very close to the SMHiggs boson.

Deviations characterized by

Model-Independence

No such thing as true, complete model independence.

More accurately labeled goal: study with “moreModel independence” than generic MSSM orGeneric extra dimensional scenario, etc.

Multiply every Higgs interaction by a parameter.

Effective Higgs Vertices: Parameterizing Deviations

Effective Theory Lagrangian

The Case of Small Deviations

J-Functions: Decay Widths

J-Functions: Decay Widths

Jt( ) J( ) Jg(gg)Jt(gg) Jt(Z)

J-Functions: Branching Ratios

Different final states are ofimportance in differentmass regions.

Etc.

J-Functions: Collider Observables

ϑ =ϑ SM (1+ Σ Jkϑ (mh )δ k +...)

J functions ( sensitivities) for (ggh)B(h )

Jt

Jb

JW

JZ

JV

J

Jg

JZ

Study Plans•Compare small expansion to full =(1+ ) result.•Catalog patterns in k for various models•Generalize effective theory NRO couplings to gauge invariant operators•Detail precision electroweak implications•Generalize analysis to exotic final states•Understand effective theory possibilities for low luminosity (10 fb-1) and high luminosity (0.1 - 1 ab-1)•Understand “basis set of observables” for each Higgs mass range that would enable determinations

Additional RemarksEmphasis here was on Feynman diagrams: Multiply allof them that involve Higgs boson by unknown k=1+k and determine from experiment.

For small deviations, expansion about small is reasonable to gauge sensitivity in shifts in observables. (Systematic uncertainties make this borderline for low luminosity especially.)

Good experimentation/measurement of other sectors helps.E.g., measurement of superpartner masses would give and g to enable check for consistency. Similar comment for heavy Higgs measurements of SUSY, or radion and KK states of X-dim.

Comprehensive measurement approach, while parametrizing deviations from expectations in model-independent effective theory formalism should be helpful path.