Improved naturalness with a heavy Higgs boson: An alternative road to CERN LHC physics

The quadratic divergences of the Higgs mass may be cancelled eitheraccidentally or by the exchange of some new particles. Alternatively its impacton naturalness may be weakened by raising the Higgs mass, which requireschanging the Standard Model below its natural cut-off. We show in detail howthis can be achieved, while preserving perturbativity and consistency with theelectroweak precision tests, by extending the Standard Model to include asecond Higgs doublet that has neither a vev nor couplings to quarks andleptons. This Inert Doublet Model yields a perturbative and completely naturaldescription of electroweak physics at all energies up to 1.5 TeV. The discretesymmetry that yields the Inert Doublet is unbroken, so that Dark Matter may becomposed of neutral inert Higgs bosons, which may have escaped detection atLEP2. Predictions are given for multilepton events with missing transverseenergy at the Large Hadron Collider, and for the direct detection of darkmatter.Comment: 25 pages; v2: published version (a reference added, minor corrections