Minimal Higgs Model Research Articles

Global fits in the coloured scalar model

In this work we study the phenomenological constraints on the parameter space of scalars carrying colour quantum numbers. In particular we constrain the Manohar-Wise model based on the addition of a SU(2) doublet and SU(3) octet to the minimal Higgs model. The fits are performed using the open-source package HEPfit. We include both theoretical constraints, such as unitarity and perturbativity, and experimental constraints, like the ones coming from flavour and electroweak observables. For the first time we combine all these results and we are able to constrain the parameters of the potential, the Yukawa couplings and the masses of the scalars.

Spontaneous parity violation and minimal Higgs models

In this paper we present a model for the spontaneous breaking of parity with two Higgs doublets and two neutral Higgs singlets which are even and odd under D-parity. The condition $ v_R >>v_L $ can be satisfied without introducing bidoublets and it is induced by the breaking of D-parity through the vacuum expectation value of the odd Higgs singlet. Examples of left-right symmetric and mirror fermions models in grand unified theories are presented.

Bimaximal mixing in an SO(10) minimal Higgs model

An SO(10) SUSY GUT model was previously presented based on a minimal set of Higgs fields. The quark and lepton mass matrices derived fitted the data extremely well and led to large ν μ − ν τ mixing in agreement with the atmospheric neutrino data and to the small-angle MSW solution for the solar neutrinos. Here we show how a slight modification leading to a non-zero up quark mass can result in bimaximal mixing for the atmospheric and solar neutrinos. The “just-so” vacuum solution is slightly favored over the large-angle MSW solution on the basis of the hierarchy required for the right-handed Majorana matrix and the more nearly-maximal mixing angles obtained.

Unification constraints on mirror fermion mass scale

The mass scale M F of conjugated, on mirror, fermions with V + A weak charged interactions is investigated in connection with grand unified models. Using extended SO(10) as an example, it has been demonstrated that this mass scale is below 1–10 TeV. Assuming that the mirror quarks are heavy (= M F ) but the mirror leptons light ( M L ≈80GeV/c 2 ), radiatively corrected values of sin 2 θ W ( M L ) are evaluated. The effect of heavy fermions on the Weinberg angle was found to be typically of order δ(sin 2 θ W ( M L )/sin 2 θ W ( M L ≲−0.6% per family. Corrections to the unification mass appear to be more significant: δ M X / M X ≲−7% per family (in the minimal Higgs model). It has been shown that expanding the Higgs sector will considerably increase the value of sin 2 θ W ( M L ) and decrease the value of M X .