Scalar representations in the light of electroweak phase transition and cold dark matter phenomenology

Abstract

The extension of the standard model's minimal Higgs sector with an inert SU (2) L scalar doublet can provide light dark matter candidate and simultaneously induce a strong phase transition for explaining Baryogenesis. There is however no symmetry reasons to prevent the extension using scalars with higher SU (2) L representations. By making random scans over the models' parameters, we show that in the light of electroweak physics constraints, strong first order electroweak phase transition and the possibility of having sub-TeV cold dark matter candidate the higher representations are rather disfavored compared to the inert doublet. This is done by computing generic perturbativity behavior and impact on electroweak phase transitions of higher representations in comparison with the inert doublet model. Explicit phase transition and cold dark matter phenomenology within the context of the inert triplet and quartet representations are used for detailed illustrations.1 Scalar singlet can also be a force carrier between SM and dark matter sector inducing strong EWPhT [58,59] or trigger EWPhT independent of being DM [60].

Theories relating baryon asymmetry and dark matter

“…A minimal extension of the SM with an extra (complex) scalar [7][8][9][10][11] or two charged singlets [12] achieves this goal, although recent data from LHC and WIMP direct detection experiments render this possibility less attractive because such a DM would have to be sub-dominant (i.e., cannot account for the total density of DM). The same applies for inert higgs extensions of the SM [13] (higher SU(2) representations were considered in [14,15]). However, models with vector-like fermions are able to produce the total DM density and BAU for a wide range of masses [16].…”

“…, which translates as a relation between asymmetries, that is D = − V where we have used the Equation (15). Therefore, in the decay of X 1 and X 1 a baryon number is generated in the visible sector and an equal and opposite baryon number is generated in the hidden sector so that the total baryon number is zero.…”

Compressing the inert doublet model

“…For these reasons, the IDM has been studied extensively as a model of dark matter (DM) [2,3], as a simple module to investigate deviations in the properties of the Higgs boson [2,4], and as a general source of new missing-energy signals in collider experiments [4,5]. Many other scenarios that postulate additional weakly-charged scalars can also be mapped onto (one or many copies of) the IDM [6,7,8,9,10,11,12,13], and the model can help to induce a strongly first-order electroweak phase transition suitable for electroweak baryogenesis [14,15,16,17,18,19].…”

Two viable large scalar multiplet models with aZ2symmetry

“…Several different models with a scalar quadruplet (isospin T = 3/2) [6][7][8][9][10][11] or scalar quintuplet (T = 2) [9,[11][12][13] have also been proposed for neutrino mass generation. The quadruplet has also been studied in the context of strengthening the electroweak phase transition [14]. Models in which the SM SU(2) L -doublet Higgs mixes with a septet (T = 3), aided by additional representations of SU(2) L , have been studied in Ref.…”