Misc,
If no Higgs then what?
(Nov 7, 2011)
Abstract
In the absence of a Higgs boson, the perturbative description of the Standard
Model ceases to make sense above a TeV. Heavy spin-1 fields coupled to W and Z
bosons can extend the validity of the theory up to higher scales. We carefully
identify regions of parameter space where a minimal addition - a single spin-1
custodial SU(2) triplet resonance - allows one to retain perturbative control
in all channels. Elastic scattering of longitudinal W and Z bosons alone seems
to permit a very large cut-off beyond the Naive Dimensional Analysis
expectation. We find however that including scattering of the spin-1 resonances
then leads to an earlier onset of strong coupling. Most importantly for LHC
searches, we define a self-consistent set-up with a well-defined range of
validity without recourse to unitarization schemes whose physical meaning is
obscure. We discuss the LHC phenomenology and the discovery reach for these
electroweak resonances and mention the possibility of a nightmare scenario with
no Higgs nor resonance within the LHC reach. Finally, we discuss the effects of
parity breaking in the heavy resonance sector which reduces the contributions
to the S parameter.
