2019/04/30 by Neda Darvishi, Apostolos Pilaftsis · 1 citation
Physics and Astronomy · #hep-ph
paper · pdf · doi:10.1103/physrevd.99.115014
published as Phys. Rev. D 99, 115014 (2019) · Minor typo corrected
arxiv created 2019/10/09 · arxiv updated 2019/10/10
We consider the Maximally Symmetric Two-Higgs Doublet Model (MS-2HDM) in which the so-called Standard Model (SM) alignment can be naturally realised as a consequence of an accidental SO(5) symmetry in the Higgs sector. This symmetry is broken (i) explicitly by renormalization-group (RG) effects and (ii) softly by the bilinear scalar mass term m212. We find that in the MS-2HDM all quartic couplings can unify at large RG scales μX ∼ 1011 - 1020 GeV. In particular, we show that quartic coupling unification can take place in two different conformally invariant points, where all quartic couplings vanish. We perform a vacuum stability analysis of the model in order to ensure that the electro-weak vacuum is sufficiently long-lived. The MS-2HDM is a minimal and very predictive extension of the SM governed by only three additional parameters: the unification scale μX, the charged Higgs mass Mh± (or m212) and tanβ, which allow one to determine the entire Higgs sector of the model. In terms of these input parameters, we present illustrative predictions of misalignment for the SM-like Higgs-boson couplings to the W^± and Z bosons and, for the first time, to the top and bottom quarks.