Dark matter with two inert doublets plus one Higgs doublet

Abstract

Following the discovery of a Higgs boson, there has been renewed interest in the general 2-Higgs-Doublet Model (2HDM). A model with One Inert Doublet plus One Higgs Doublet (I(1+1)HDM), where one of the scalar doublets is "inert" (since it has no vacuum expectation value and does not couple to fermions) has an advantage over the 2HDM since it provides a good Dark Matter (DM) candidate, namely the lightest inert scalar. Motivated by the existence of three fermion families, here we consider a model with two scalar doublets plus one Higgs doublet (I(2+1)HDM), where the two scalar doublets are inert. The I(2+1)HDM has a richer phenomenology than either the I(1+1)HDM or the 2HDM. We discuss the new regions of DM relic density in the I(2+1)HDM with simplified couplings and address the possibility of constraining the model using recent results from the Large Hadron Collider (LHC) and DM direct detection experiments.

Effects of two inert scalar doublets on Higgs boson interactions and the electroweak phase transition

“…(12), and the parameter limitations in Eq. (13). We notice that many of the R γγ values are close to 1 and within the allowed ranges from ATLAS and CMS.…”

“…Scenarios incorporating a second Higgs doublet are of course highly popular in the literature [4,5]. Of late models with three scalar weak doublets have also been gaining interest [6][7][8][9][10][11][12][13][14], as they can provide dark matter (DM) candidates [13] and/or an important ingredient for the mechanism that generates neutrino mass [14].…”

Observable heavy Higgs dark matter

“…(see figure 12a), as studied in [14]. However, coannhilation with H 2 , A 1 and A 2 may change the results significantly (see figure 12b).…”

“…In [14], we have studied in detail the theoretical constraints; positivity of the mass eigenstates, bounded-ness of the potential, positive-definite-ness of the Hessian, and the LEP limits on the parameters of the potential. These limits have been taken into account in the present paper.…”

“…So, unless ∆ is forced to be small by limits put on µ 2 12 , one should also consider a case where the second doublet is decoupled from the first, leading to a scenario which was not listed in [14]. Therefore, in the very heavy mass region one can consider:…”