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.