Abstract
The Higgs sector of the Next-to-Minimal Two-Higgs-Doublet Model (N2HDM) is obtained from the Two-Higgs-Doublet Model (2HDM) containing two complex Higgs doublets, by adding a real singlet field. In this paper, we analyse the vacuum structure of the N2HDM with respect to the possibility of vacuum instabilities. We show that while one type of charge- and CP-preserving vacuum cannot coexist with deeper charge-or CP-breaking minima, there is another type of vacuum whose stability is endangered by the possible occurrence of deeper charge- and CP-breaking minima. Analytical expressions relating the depth of different vacua are deduced. Parameter scans of the model are carried out that illustrate the regions of parameter space where the vacuum is either stable or metastable as well as the regions where tunnelling to deeper vacua gives rise to a too short lifetime of the vacuum. Taking other experimental and theoretical constraints into account, we find that the vacuum stability constraints have an important impact on the phenomenology of the N2HDM.
Highlights
The CP symmetry (CP breaking) or the conservation of electric charge, in supersymmetric models even color breaking minima can occur
There is the possibility of a second EW minimum but with a wrong vacuum expectation value (VEV) v = 246 GeV, as for example in the 2-Higgs Doublet Model (2HDM) where this situation was named “panic vacuum” [8,9,10,11,12]
The N2HDM, which is obtained upon extension of the 2HDM with a real singlet field, was shown to exhibit a different vacuum structure than the 2HDM
Summary
The CP symmetry (CP breaking) or the conservation of electric charge (charge breaking), in supersymmetric models even color breaking minima can occur. The developed code BSMPT [19] allows for studies of the vacuum structure at NLO (at zero and at finite temperature) of arbitrary user-defined BSM extensions This is the case for Vevacious [20, 21], designed for general BSM models, including one-loop and temperature effects. To reduce the large number of parameters of the scalar potential, and to allow for the possibility of interesting phenomenology, such as dark matter, three discrete symmetries are imposed: (a) a Z2 symmetry in which one of the doublets is affected by a sign change, Φ1 → Φ1, Φ2 → −Φ2 and ΦS → ΦS; (b) another Z2 symmetry which leaves the doublets unchanged but changes the sign of the singlet, Φ1 → Φ1, Φ2 → Φ2 and ΦS → −ΦS; (c) the standard CP symmetry, Φ1 → Φ∗1 and Φ2 → Φ∗2 — since the singlet is real, the CP transformation does not affect it. After imposing these symmetries only terms quadratic and quartic in the fields are allowed and the most general scalar potential is given by
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
