scholarly journals Electroweak baryogenesis and gravitational waves in a composite Higgs model with high dimensional fermion representations

2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
Ke-Pan Xie ◽  
Ligong Bian ◽  
Yongcheng Wu

Abstract We study electroweak baryogenesis in the SO(6)/SO(5) composite Higgs model with the third generation quarks being embedded in the 20′ representation of SO(6). The scalar sector contains one Higgs doublet and one real singlet, and their potential is given by the Coleman-Weinberg potential evaluated from the form factors of the lightest vector and fermion resonances. We show that the resonance masses at $$ \mathcal{O}\left(1\sim 10\kern0.5em \mathrm{TeV}\right) $$ O 1 ∼ 10 TeV can generate a potential that triggers the strong first-order electroweak phase transition (SFOEWPT). The CP violating phase arising from the dimension-6 operator in the top sector is sufficient to yield the observed baryon asymmetry of the universe. The SFOEWPT parameter space is detectable at the future space-based detectors.

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Sebastian Baum ◽  
Marcela Carena ◽  
Nausheen R. Shah ◽  
Carlos E. M. Wagner ◽  
Yikun Wang

Abstract Electroweak baryogenesis is an attractive mechanism to generate the baryon asymmetry of the Universe via a strong first order electroweak phase transition. We compare the phase transition patterns suggested by the vacuum structure at the critical temperatures, at which local minima are degenerate, with those obtained from computing the probability for nucleation via tunneling through the barrier separating local minima. Heuristically, nucleation becomes difficult if the barrier between the local minima is too high, or if the distance (in field space) between the minima is too large. As an example of a model exhibiting such behavior, we study the Next-to-Minimal Supersymmetric Standard Model, whose scalar sector contains two SU(2) doublets and one gauge singlet. We find that the calculation of the nucleation probabilities prefers different regions of parameter space for a strong first order electroweak phase transition than the calculation based solely on the critical temperatures. Our results demonstrate that analyzing only the vacuum structure via the critical temperatures can provide a misleading picture of the phase transition patterns, and, in turn, of the parameter space suitable for electroweak baryogenesis.


Physics ◽  
2021 ◽  
Vol 3 (2) ◽  
pp. 275-289
Author(s):  
Arnab Chaudhuri ◽  
Maxim Yu. Khlopov

We revisit the possibility of first order electroweak phase transition (EWPT) in one of the simplest extensions of the Standard Model scalar sector, namely the two-Higgs-doublet model (2HDM). We take into account the ensuing constraints from the electroweak precision tests, Higgs signal strengths and the recent LHC bounds from direct scalar searches. By studying the vacuum transition in 2HDM, we discuss in detail the entropy released in the first order EWPT in various parameter planes of a 2HDM.


2019 ◽  
Vol 64 (8) ◽  
pp. 710
Author(s):  
P. Minaiev ◽  
V. Skalozub

We investigate the electroweak phase transition (EWPT) in the Minimal (One Higgs doublet) Standard Model (SM) with account for the spontaneous generation of magnetic and chromo-magnetic fields. As it is known, in the SM for the mass of a Higgs boson greater than 75 GeV, this phase transition is of the second order. But, according to Sakharov’s conditions for the formation of the baryon asymmetry in the early Universe, it has to be strongly of the first order. In the Two Higgs doublets SM, there is a parametric space, where the first-order phase transition is realized for the realistic Higgs boson mass mH = 125 GeV. On the other hand, in the hot Universe, the spontaneous magnetization of a plasma had happened. The spontaneously generated (chromo) magnetic fields are temperature-dependent. They influence the EWРT. The color chromomagnetic fields B3 and B8 are created spontaneously in the gluon sector of QCD at a temperature T > Td higher the deconfinement temperature Td. The usual magnetic field H has also to be spontaneously generated. For T close to the TEWPT , these magnetic fields could change the kind of the phase transition.


1994 ◽  
Vol 05 (02) ◽  
pp. 379-381
Author(s):  
K. FARAKOS ◽  
K. KAJANTIE ◽  
K. RUMMUKAINEN ◽  
M. SHAPOSHNIKOV

According to the electroweak baryogenesis scenario the matter-antimatter asymmetry of the Universe was created shortly after the Big Bang, during the electroweak phase transition. This process depends strongly on the detailed nature of the electroweak phase transition. For realistic Higgs particle masses, the standard perturbative analysis indicates that the transition is at most only weakly first order. We have studied the transition with non-perturbative lattice Monte Carlo simulations. We found large non-perturbative effects; in particular, the phase transition is a strongly first order one, at least up to Higgs mass of about 85 GeV. This makes electroweak baryogenesis a viable scenario with a Higgs mass not exceeding 85 GeV.


2017 ◽  
Vol 26 (10) ◽  
pp. 1750114 ◽  
Author(s):  
Archil Kobakhidze ◽  
Adrian Manning ◽  
Jason Yue

Within the Standard Model with nonlinearly realized electroweak symmetry, the LHC Higgs boson may reside in a singlet representation of the gauge group. Several new interactions are then allowed, including anomalous Higgs self-couplings, which may drive the electroweak phase transition to be strongly first-order. In this paper, we investigate the cosmological electroweak phase transition in a simplified model with an anomalous Higgs cubic self-coupling. We look at the feasibility of detecting gravitational waves produced during such a transition in the early universe by future space-based experiments. We demonstrate an intriguing interplay between collider measurements of the Higgs self-coupling and these potential gravitational wave measurements. We find that for the range of relatively large cubic couplings, [Formula: see text], [Formula: see text]mHz frequency gravitational waves can be observed by eLISA, while BBO will potentially be able to detect waves in a wider frequency range, [Formula: see text][Formula: see text]mHz.


2018 ◽  
Vol 168 ◽  
pp. 05001 ◽  
Author(s):  
Toshinori Matsui

Among various scenarios of baryon asymmetry of the Universe, electroweak baryogenesis is directly connected with physics of the Higgs sector. We discuss spectra of gravitational waves which are originated by the strongly first order phase transition at the electroweak symmetry breaking, which is required for a successful scenario of electroweak baryogenesis. In the Z3 symmetric singlet scalar model, the significant gravitational waves are caused by the multi-step phase transition. We show that the model can be tested by measuring the characteristic spectra of the gravitational waves at future interferometers such as LISA and DECIGO.


2017 ◽  
Vol 2017 ◽  
pp. 1-10
Author(s):  
Mina Saeedhosseini ◽  
Ali Tofighi

We consider an extension of the Standard Model (SM) with additional gauge singlets which exhibits a strong first-order phase transition. Due to this first-order phase transition in the early universe gravitational waves are produced. We estimate the contributions such as the sound wave, the bubble wall collision, and the plasma turbulence to the stochastic gravitational wave background, and we find that the strength at the peak frequency is large enough to be detected at future gravitational interferometers such as eLISA. Deviations in the various Higgs boson self-couplings are also evaluated.


2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Ke-Pan Xie

Abstract An electroweak baryogenesis (EWBG) mechanism mediated by τ lepton transport is proposed. We extend the Standard Model with a real singlet scalar S to trigger the strong first-order electroweak phase transition (SFOEWPT), and with a set of leptophilic dimension-5 operators to provide sufficient CP violating source. We demonstrate this model is able to generate the observed baryon asymmetry of the universe. This scenario is experimentally testable via either the SFOEWPT gravitational wave signals at the next-generation space-based detectors, or the pp → h* → SS → 4τ process (where h* is an off-shell Higgs) at the hadron colliders. A detailed collider simulation shows that a considerable fraction of parameter space can be probed at the HL-LHC, while almost the whole parameter space allowed by EWBG can be reached by the 27 TeV HE-LHC.


2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Wei Su ◽  
Anthony G. Williams ◽  
Mengchao Zhang

Abstract The electroweak phase transition can be made first order by extending the Standard Model (SM) Higgs sector with extra scalars. The same new physics can explain the matter-antimatter asymmetry of the universe by supplying an extra source of CP violation and sphaleron processes. In this paper we study the existence of strong first order electroweak phase transition (SFOEWPT) in the type-I and type-II two Higgs doublet models (2HDM). We focus on how the SFOEWPT requirements constraint the spectrum of non-SM Higgs. Through the parameter space scan, we find that SFOEWPT suggests an upper limit on the masses of heavy Higgs $$ {m}_{A/H/{H}^{\pm }} $$ m A / H / H ± , which is around 1 TeV. High temperature expansion and Higgs vacuum uplifting is used for an analytical understanding of our results. After taking into account the probe ability on SFOEWPT from theoretical constraints, Higgs and Z-pole precision measurements up to the one-loop level at future Higgs & Z factories, sizeable loop corrections require $$ {m}_{A/{H}^{\pm }}-{m}_H $$ m A / H ± − m H ∈ (100, 250) GeV to meet SFOEWPT condition for Type-II 2HDM, and $$ \left|{m}_{A/{H}^{\pm }}-{m}_H\right| $$ m A / H ± − m H ∈ (100, 350) GeV or $$ \left|{m}_A-{m}_{H/{H}^{\pm }}\right| $$ m A − m H / H ± ∈ (100, 350) GeV for Type-I 2HDM.


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