Real-time simulations and the electroweak phase transition

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.

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ATCO radar training assessment and flight efficiency: the correlation between trainees’ scores and fuel consumption in real-time simulations

The Aeronautical Journal ◽

10.1017/aer.2020.142 ◽

2020 ◽

pp. 1-17

Author(s):

T. Rogošić ◽

B. Juričić ◽

F. Aybek Çetek ◽

Z. Kaplan

Keyword(s):

Real Time ◽

Fuel Consumption ◽

Basic Training ◽

Air Traffic Controller ◽

Training Assessment ◽

Assessment Scores ◽

Human In The Loop ◽

Assessment Standards ◽

Two Parameters ◽

Real Time Simulations

ABSTRACT Air traffic controller training is highly regulated but lacks prescribed common assessment criteria and methods to evaluate trainees at the level of basic training and consideration of how trainees in fluence flight efficiency. We investigated whether there is a correlation between two parameters, viz. the trainees’ assessment score and fuel consumption, obtained and calculated after real-time human-in-the-loop radar simulations within the ATCOSIMA project. Although basic training assessment standards emphasise safety indicators, it was expected that trainees with higher assessment scores would achieve better flight efficiency, i.e. less fuel consumption. However, the results showed that trainees’ assessment scores and fuel consumption did not correlate in the expected way, leading to several conclusions.

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Dark Matter production from relativistic bubble walls

Journal of High Energy Physics ◽

10.1007/jhep03(2021)288 ◽

2021 ◽

Vol 2021 (3) ◽

Author(s):

Aleksandr Azatov ◽

Miguel Vanvlasselaer ◽

Wen Yin

Keyword(s):

Phase Transition ◽

Dark Matter ◽

Electroweak Phase Transition ◽

First Order ◽

Matter Production ◽

First Order Phase Transition ◽

Relic Abundance ◽

Higgs Portal ◽

First Order Phase ◽

Gravitational Background

Abstract In this paper we present a novel mechanism for producing the observed Dark Matter (DM) relic abundance during the First Order Phase Transition (FOPT) in the early universe. We show that the bubble expansion with ultra-relativistic velocities can lead to the abundance of DM particles with masses much larger than the scale of the transition. We study this non-thermal production mechanism in the context of a generic phase transition and the electroweak phase transition. The application of the mechanism to the Higgs portal DM as well as the signal in the Stochastic Gravitational Background are discussed.

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A critical look at the electroweak phase transition

Journal of High Energy Physics ◽

10.1007/jhep12(2020)136 ◽

2020 ◽

Vol 2020 (12) ◽

Author(s):

Andreas Ekstedt ◽

Johan Löfgren

Keyword(s):

Phase Transition ◽

Generic Model ◽

Electroweak Symmetry ◽

Electroweak Phase Transition ◽

Gauge Dependence ◽

Perturbative Methods ◽

The Standard Model ◽

Gauge Fixing ◽

Infrared Divergences ◽

General Gauge

Abstract The electroweak phase transition broke the electroweak symmetry. Perturbative methods used to calculate observables related to this phase transition suffer from severe problems such as gauge dependence, infrared divergences, and a breakdown of perturbation theory. In this paper we develop robust perturbative tools for dealing with phase transitions. We argue that gauge and infrared problems are absent in a consistent power-counting. We calculate the finite temperature effective potential to two loops for general gauge-fixing parameters in a generic model. We demonstrate gauge invariance, and perform numerical calculations for the Standard Model in Fermi gauge.

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Nucleation is more than critical: A case study of the electroweak phase transition in the NMSSM

Journal of High Energy Physics ◽

10.1007/jhep03(2021)055 ◽

2021 ◽

Vol 2021 (3) ◽

Author(s):

Sebastian Baum ◽

Marcela Carena ◽

Nausheen R. Shah ◽

Carlos E. M. Wagner ◽

Yikun Wang

Keyword(s):

Phase Transition ◽

Parameter Space ◽

Local Minima ◽

Critical Temperatures ◽

Electroweak Phase Transition ◽

First Order ◽

Vacuum Structure ◽

The Universe ◽

Scalar Sector

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.

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