A New Approach to Electroweak Symmetry Non-Restoration

Abstract

Electroweak symmetry non-restoration up to high temperatures well above the electroweak scale offers new alternatives for baryogenesis. We propose a new approach for electroweak symmetry non-restoration via an inert Higgs sector that couples to the Standard Model Higgs as well as an extended scalar singlet sector. We implement renormalization group improvements and thermal resummation, necessary to evaluate the effective potential spanning over a broad range of energy scales and temperatures. We present examples of benchmark scenarios that allow for electroweak symmetry non-restoration all the way up to hundreds of TeV temperatures, and also feature suppressed sphaleron washout factors down to the electroweak scale. Our method for transmitting the Standard Model broken electroweak symmetry to an inert Higgs sector has several intriguing implications for (electroweak) baryogenesis, early universe thermal histories, and can be scrutinized through Higgs physics phenomenology and electroweak precision measurements at the HL-LHC.

Electroweak Symmetry Non-Restoration from Dark Matter

“…Indeed, it may be tempting to draw a connection between the three generations of the Standard Model and the n χ = 3 SNR model, which is seen to work well in Figure 6. The first detailed analysis of the effect of the second Higgs doublet on SNR was recently performed in [20] for the case of SNR with new singlet scalars, this work also predicting a lower number of SNR scalars (order-20) compared to the original single Higgs models [14][15][16]. Moreover, these authors presented a detailed phenomenological analysis regarding detection prospects of the second Higgs doublet, which is highly relevant to the models outlined in this work.…”

“…is related to the previous one by a custodial symmetry (weakly broken at one-loop level), the term hence vanishes if the custodial symmetry is imposed together with U (1)H2 [20,30]. 4 This coupling structure also avoids dangerous tree-level flavor changing neutral currents, similar to the classic Type I two Higgs doublet model [31].…”

“…Neglecting the phase space suppression factor, this results in a bound λ 12 0.007. In the opposite case m h1 < 2 m h2 the strongest bound on λ 12 was derived from a modification of the 1-loop h 1 -photon coupling [20] (assuming m h2 = m h1 /2) and reads λ 12 0.4. This bound will potential be improved by about one order of magnitude at HL-LHC [51].…”

“…The general concept of symmetry non-restoration (SNR) was first explored by Weinberg [1] and then expanded upon in [2][3][4][5][6][7][8][9][10][11][12][13]. Recently, scenarios of SNR for the electroweak sector, and the associated phenomenological observables, have become a topic of investigation [14][15][16][17][18][19][20][21]. Electroweak SNR is of special interest in the context of certain baryogenesis scenarios [22].…”

“…We show that this issue can be resolved by extending the scenario with a second Higgs doublet 1 . Besides linking SNR with DM, such an extension allows one to significantly decrease the number of new degrees of freedom required for SNR [16,20]; notably, the original one-Higgs SNR mechanisms required at least O (10) new Dirac fermions, or at least O(100) new singlet scalars.…”