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Dorota Sokolowska

Publications and source records attributed to Dorota Sokolowska.

28 records · Page 2Linked to original sources

2HDM with Z_2 symmetry in light of new LHC data

Properties of the Z_2-symmetric Two Higgs Doublet Models (2HDM) are discussed and confronted with new LHC data for a 125 GeV Higgs particle. The particle discovered at LHC in 2012 has properties expected for it in the Standard Model (SM), with a possible enhancement in the two-photon channel. SM-like Higgs scenarios can be realized in the Two Higgs Doublet Models with Z_2 (D) symmetry within the normal Mixed Model (with scalar sector as in MSSM) and the Inert Doublet Model (IDM), where a good Dark Matter (DM) candidate is present. Here we discuss both of the models.

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Inert Doublet Model with a 125 GeV Higgs

A 125 GeV Higgs-like particle discovered at the LHC in 2012 has properties expected for it in the Standard Model (SM), with a possible enhancement in the two-photon channel. Such SM-like Higgs scenario can be realized within the Inert Doublet Model (IDM) - a version of the Two Higgs Doublet Model with an exact discrete D (Z_2-type) symmetry. In this model one SU(2) doublet plays the role of the SM Higgs doublet with one SM-like Higgs boson. The second doublet has no vacuum expectation value and does not interact with fermions. Among four scalars constituting this D-odd doublet the lightest one is stable, being if neutral a good DM candidate with the right relic density. In this paper an analysis of the two-photon Higgs decay rate in IDM, respecting theoretical and other experimental constraints, is presented. The enhancement in the two-photon channel is possible only if invisible channels are closed, with the enhancement R_{γγ}>1.2 for masses of DM and charged scalars below 154 GeV. The temperature evolution of the Universe to the Inert phase (described by the IDM) in T^2 approximation is presented and all possible sequences of phase transitions in one, two and three steps are analyzed. Going beyond this approximation by using an effective potential approach with one-loop T=0 Weinberg-Coleman term and temperature dependent effective potential at T\not =0 we address the question, whether the strong first-order phase transition needed for baryogenesis can be realized in IDM. A region with a good DM relic density and a strong first-order phase transition is established, and discussed in the light of the XENON-100 data.

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Dark matter data and quartic self-couplings in Inert Doublet Model

We analyse the thermal evolution of the Universe in the Inert Doublet Model for three viable regions of Dark Matter mass: low, medium and high DM mass. Those three regions exhibit different behaviour in the possible types of evolution. We argue that the quartic self-couplings in IDM are significant parameters for the astrophysical analysis.

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Dark Matter data and constraints on quartic couplings in IDM

We analyse the thermal evolution of the Universe in the Inert Doublet Model for three regions of Dark Matter masses: low mass (4-8) GeV, medium mass (30-80) GeV and high mass (500-1000) GeV. Those three regions of DM mass exhibit different behaviour, both in the possible types of evolution and in the energy relic density values. In this analysis we use the masses of the scalar particles as the input parameters to constrain the two self-couplings between neutral scalars: $λ_{345},λ_2$. These couplings are used to construct the parameter space where different types of evolution may be presented. We discuss the influence of the scalar masses on the type of the evolution. We also discuss the importance of the $λ_2$ self-coupling. We argue, that the astrophysical data along with the positivity constraints simultaneously constrain both $λ_{345}$ and $λ_2$ self-couplings.

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The Inert Doublet Model and evolution of the Universe

Inert Doublet Model (IDM) is a minimal extension of the Standard Model with the second scalar doublet that may provide a Dark Matter candidate. In this paper we consider the different variants of the evolution of the Universe after inflation, that lead towards the Inert phase today.

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Temperature evolution of physical parameters in the Inert Doublet Model

Inert Doublet Model is a minimal extension of the Standard Model with the second scalar doublet that may provide a Dark Matter candidate. In this paper we consider different variants of the evolution of the Universe after inflation, that lead towards the Inert phase today. We extend our previous analysis, in particular by discussing the co-existence of minima and providing numerical examples of the evolutions of the mass parameters for the different types of the history of the Universe. We take into account the existing constraints, including the relict density data.

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Inert Model and evolution of the Universe

We consider evolution of the Universe after EWSB leading to the present inert phase, containing a SM-like Higgs boson and scalar dark particles, among them a Dark Matter candidate. We address the question, if there is a possibility to have a sequence of the phase transitions instead of a single one leading directly from EW symmetric phase to the inert one.

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Constraining the Dark 2HDM

The Dark 2HDM (called also the Inert Doublet Model) is the version of the Two-Higgs-Doublet Model with an exact $Z_2$ symmetry. It contains the SM-like Higgs boson $h$ and dark scalars $H$,$H^+,H^-$,$A$. Only dark scalars have odd $Z_2$ parity and therefore the lightest of them can be a dark matter candidate. The comparison of such model and of the standard 2HDM with an explicit $Z_2$ symmetry is given.

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On distinguishing the direct and spontaneous CP violation in 2HDM

The most general Two Higgs Doublet Model (2HDM) allows both for the explicit and the spontaneous CP violation in the scalar sector. Here we discuss CP violation in terms of basis-independent quantities and show how using two different sets of known CP-odd weak-basis invariants one can distinguish between CP conservation, explicit CP violation and spontaneous CP violation. The special case of CP violation without CP mixing, in which the neutral Higgs gauge boson interaction respects CP while Higgs self-interaction violates CP symmetry, is also presented.

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