S(3) flavoured Higgs model trilinear self-couplings

Abstract: In this work, we analyze the Higgs sector of the minimal $S(3)$-invariant extension of the Standard Model is performed. Considering three Higgs fields, which are SU(2) doublets, and CP invariant, we compute the exact and analytical physical Higgs boson masses in terms of the Higgs potential parameters and the scalar Higgs matrix rotation angle $\theta_S$ and $w_3$ ($\tan\theta_P=\tan\theta_C=\tan^{-1}\omega_3$), related to the pseudoscalar and charged Higgs matrix rotation angles $\theta_P$ and $\theta_C$ respectively. Furthermore, within this model we can also write down in an explicit form the trilinear self-couplings $\lambda_{ijk}$ in terms of the Higgs masses and two free parameters, $\theta_S$ and $w_3$. Moreover, we show that the Higgs masses and trilinear Higgs bosons self-couplings are closely linked to the Higgs potential structure given by the discrete symmetry $S(3)$, which can be helpful to distinguish this model from other extensions. In our analysis the lightest Higgs boson mass is taken to be fixed to 125 GeV. In concordance with the results reported in the literature for other Standard Model extensions, it find that the numerical values $\lambda_{ijk}$ of the minimal $S(3)$-invariant extension of the Standard Model are significantly different from the trilinear Higgs self-coupling of the Standard Model.