Remarks on the minimal vectorial standard model

We explore the available parameter space of the minimal vectorial standard model. In this theory, the gauge currents are initially vectorial but the Higgs sector produces chiral mass eigenstates, leading to a set of heavy right-handed mirror particles. We describe the phenomenology of the residual parameter space and suggest that the model will be readily tested at the LHC.

Figure 1

The contributions to the electroweak parameters are shown for a sample of 3000 randomly distributed models as described in the text. The violet (dark gray) region highlights those that satisfy the constraints with a light Higgs. The $U=0$, 90% C.L. contours are shown assuming SM Higgs masses $M_H=117$, 340, and 1000 GeV.

Figure 2

The effect the variation of the Higgs (left panel) and mirror fermion (right panel) masses have on the $S$, $T$, $U$ parameters. All curves intersect at $(m_h,m_A,m_H,m_{H\pm })=(125,900,130,580)\mathrm{GeV}$ and $(m_N,m_E,m_U,m_D)=(53,250,250,190)\mathrm{GeV}$.

Figure 3

The allowed region [in violet (dark gray)] in a sample of 3000 randomly distributed models [in light blue (light gray)] between $m_{\mathrm{initial}}$ and $m_{\mathrm{final}}=m_{\mathrm{initial}}+10\mathrm{GeV}$. The initial values of the fermion and Higgs masses are taken to be (a) $(m_N,m_E,m_U,m_D)=(100,580,580,320)$, $(m_h,m_A,m_H,m_{H\pm })=(120,4520,120,800)\mathrm{GeV}$, and (b) $(m_N,m_E,m_U,m_D)=(260,1500,1500,830)$ and $(m_h,m_A,m_H,m_{H\pm })=(115,9035,120,2400)\mathrm{GeV}$. In both cases we find $U\approx 0.4$.

Figure 4

Contours of constant $v_c(T_c)/T_c$. Dark regions represent the parameter space with $v_c(T_c)/T_c>1$ and $M/T_c<1.6$, for which the high temperature expansion is trusted. Units are GeV for masses, and we take one (left panel) and three (right panel) families of mirror particles. We use $m_t=175\mathrm{GeV}$ for the top quark and $m_N=m_E=m_U=m_D=100\mathrm{GeV}$ for mirror fermions.

Figure 5

The allowed region [in violet (dark gray)] for a sample of 3000 randomly distributed models [in light blue (light gray)] using only one generation of mirror particles. All these models can lead to baryogenesis. However, only the points in red represent those that respect the electroweak precession data (we find that the models in violet have $0<U<0.1$). The $U=0$, 90% C.L. contour is shown assuming SM Higgs masses $M_H=117\mathrm{GeV}$.

Figure 6

Decay channels of the leptonic mirror particles which proceed through mixing with the regular leptons. The circle represents a mass mixing insertion from (18).