Fixed point scenario in the Two Higgs Doublet Model

We consider the renormalisation group flow of Higgs and Yukawa couplings within the simplest non–supersymmetric two Higgs doublet extension of the Standard Model (SM). In this model the couplings are adjusted so that the multiple point principle (MPP) assumption, which implies the existence of a large set of degenerate vacua at some high energy scale Λ, is realised. When the top quark Yukawa coupling at the scale Λ is large, the solutions of RG equations in this MPP inspired 2 Higgs Doublet Model (2HDM) converge to quasi–fixed points. We analyse the Higgs spectrum and couplings in the quasi–fixed point scenario and compute a theoretical upper bound on the lightest Higgs boson mass. When the scale Λ is low, the coupling of the SM–like Higgs scalar to the top quark can be significantly larger in the considered model than in the SM, resulting in the enhanced production of Higgs bosons at the LHC. 1 On leave of absence from the Theory Department, ITEP, Moscow, Russia