scholarly journals Simulations of a bubble wall interacting with an electroweak plasma

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Zong-Gang Mou ◽  
Paul M. Saffin ◽  
Anders Tranberg

Abstract We perform large-scale real-time simulations of a bubble wall sweeping through an out-of-equilibrium plasma. The scenario we have in mind is the electroweak phase transition, which may be first order in extensions of the Standard Model, and produce such bubbles. The process may be responsible for baryogenesis and can generate a background of primordial cosmological gravitational waves. We study thermodynamic features of the plasma near the advancing wall, the generation of Chern-Simons number/Higgs winding number and consider the potential for CP-violation at the wall generating a baryon asymmetry. A number of technical details necessary for a proper numerical implementation are developed.

2021 ◽  
Vol 36 (05) ◽  
pp. 2150024
Author(s):  
Shehu AbdusSalam ◽  
Mohammad Javad Kazemi ◽  
Layla Kalhor

For a cosmological first-order electroweak phase transition, requiring no sphaleron washout of baryon number violating processes leads to a lower bound on the strength of the transition. The velocity of the boundary between the phases, the so-called bubble wall, can become ultrarelativistic if the friction due to the plasma of particles is not sufficient to retard the wall’s acceleration. This bubble “runaway” should not occur if a successful baryon asymmetry generation due to the transition is required. Using Boedeker–Moore criterion for bubble wall runaway, within the context of an extension of the Standard Model of particle physics with a real gauge-single scalar field, we show that a nonrunaway transition requirement puts an upper bound on the strength of the first-order phase transition.


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.


2013 ◽  
Vol 2013 ◽  
pp. 1-9
Author(s):  
Wei-Shu Hou ◽  
Masaya Kohda

Electroweak baryogenesis is an attractive scenario for explaining the baryon asymmetry of the universe. However, it does not work within the standard model due to two reasons: (1) the strength of CP violation from the Kobayashi-Maskawa mechanism with three generations is too small; (2) the electroweak phase transition is not first order for the experimentally allowed Higgs boson mass. We discuss possibilities to solve these problems by introducing a fourth generation of fermions and how electroweak baryogenesis might be revived. We also discuss briefly the recent observation of a Higgs-like boson with mass around 125 GeV, which puts the fourth generation in a difficult situation, and the possible way out.


1993 ◽  
Vol 71 (5-6) ◽  
pp. 227-236 ◽  
Author(s):  
M. E. Carrington

There has been much recent interest in the finite-temperature effective potential of the standard model in the context of the electroweak phase transition. We review the calculation of the effective potential with particular emphasis on the validity of the expansions that are used. The presence of a term that is cubic in the Higgs condensate in the one-loop effective potential appears to indicate a first-order electroweak phase transition. However, in the high-temperature regime, the infrared singularities inherent in massless models produce cubic terms that are of the same order in the coupling. In this paper, we discuss the inclusion of an infinite set of these terms via the ring-diagram summation, and show that the standard model has a first-order phase transition in the weak coupling expansion.


2018 ◽  
Vol 2018 ◽  
pp. 1-5
Author(s):  
M. Gogberashvili

We suggest using Einstein’s static universe metric for the metastable state after reheating, instead of the Friedman-Robertson-Walker spacetime. In this case, strong static gravitational potential leads to the effective reduction of the Higgs vacuum expectation value, which is found to be compatible with the Standard Model first-order electroweak phase transition conditions. Gravity could also increase the CP-violating effects for particles that cross the new phase bubble walls and thus is able to lead to the successful electroweak baryogenesis scenario.


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.


2017 ◽  
Vol 32 (14) ◽  
pp. 1750087 ◽  
Author(s):  
Neil D. Barrie ◽  
Archil Kobakhidze

We propose a new mechanism for generating both luminous and dark matter during cosmic inflation. According to this mechanism, ordinary and dark matter carry common charge which is associated with an anomalous U(1)[Formula: see text] group. Anomaly terms source [Formula: see text] and U(1)[Formula: see text] charge violating processes during inflation, producing corresponding nonzero Chern–Simons numbers which are subsequently reprocessed into baryon and dark matter densities. The general framework developed is then applied to two possible extensions of the Standard Model with anomalous gauged [Formula: see text] and [Formula: see text], each with an additional dark matter candidate. In each scenario, we consider the parameter choices that predict the correct dark matter to baryonic matter density ratio and baryon asymmetry. Interestingly, under these conditions, for the U(1)[Formula: see text] extension we obtain a prediction for the mass of the dark matter candidate which is independent of the other choice of parameters, when assuming an [Formula: see text] and [Formula: see text].


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.


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