Enhanced Higgs boson production and avoidance of CP-violation and FCNC in the MPP inspired 2HDM

The multiple point principle (MPP) can be used to suppress non–diagonal flavour transitions and CP violation in the two Higgs doublet extension of the standard model. We discuss the quasi–fixed point scenario in the MPP inspired two Higgs doublet model which leads to the enhanced production of Higgs particles at the LHC if the MPP scale Λ ≃ 10− 100TeV. 1. Multiple point principle and custodial symmetries The violation of CP invariance and the existence of tree–level flavor–changing neutral currents (FCNC) are generic features of SU(2)W × U(1)Y theories with two Higgs doublets. Indeed the couplings m23, λ5, λ6 and λ7 in the Higgs potential of the two–Higgs doublet model (2HDM) V = m1|H1| +m2|H2| − [ m23H † 1 H2 + h.c. ] + λ1 2 |H1| + λ2 2 |H2| + λ3|H1||H2| +λ4|H 1H2| + [ λ5 2 (H 1 H2) 2 + λ6|H1|(H 1H2) + λ7|H2|(H † 1 H2) + h.c. ] (1) can be complex inducing CP–violation. Although one can eliminate the violation of CP invariance and tree–level FCNC transitions by imposing a discrete Z2 symmetry, such a symmetry leads to the formation of domain walls in the early Universe which would create unacceptably large anisotropies in the cosmic microwave background radiation. Here we consider the multiple point principle (MPP) [1] as a possible mechanism for the suppression of FCNC and CP–violation effects. MPP postulates the existence of the maximal number of phases with the same energy density which are allowed by a given theory [1]. When applied to the 2HDM the multiple point principle implies the existence of a large set of degenerate vacua at some high energy scale Λ (MPP scale) that can be parametrised as