Electroweak Phase Transition, Gravitational Waves and Dark Matter in Two Scalar Singlet Extension of The Standard Model

In this paper, the electroweak phase transition, the gravitational waves and the dark matter issues are investigated in two scalar singlet extension of the standard model. The detectability of the gravitational wave signals are discussed by comparing the results with the sensitivity curves of $\mathbf{eLISA}$, $\mathbf{ALIA}$, $\mathbf{DECIGO}$ and $\mathbf{BBO}$ detectors. It is shown that the results support the recent reports on the dark matter relic density by $\mathbf{Planck}$ $\mathbf{2018}$ collaboration and the direct detection experiment by $\mathbf{XENON1T}$ $\mathbf{2018}$ collaboration.Comment: 18 pages, 2 figures (4 subfigures), 4 tables, final version to match the published versio

Mass of the Stabilized Radion in the Limit of Finite Quartic Coupling

We present an exact treatment of the modulus stabilization condition with the general boundary conditions of the bulk scalar field in the Randall-Sundrum model. We find analytical expressions for the value of the modulus and the mass of the radion.Comment: 11 pages, 3 figures, Accepted for publication in AHE

Dominant Spacetime in Three Dimensional de Sitter Gravity

In three dimensions, Kerr-de Sitter spacetime as a solution of Einstein gravity with positive cosmological constant has a single cosmological horizon. The flat-space limit (zero cosmological constant limit) of this spacetime is well-defined and yields the flat-space cosmological solution which is a significant spacetime in the context of flat-space holography. In this paper, we calculate the free energy of this spacetime and compare it with the free energy of the three-dimensional de Sitter spacetime. We investigate which one of these two spacetimes will dominate in the semi-classical approximation for estimating the partition function. It is shown that for the same temperature of cosmological horizon of two spacetimes this is the de Sitter spacetime which is always dominant. Hence, contrary to asymptotically flat and asymptotically AdS spacetimes, there is no phase transition in three dimensional de Sitter gravity.Comment: 11 pages, V2: clarifications added, published versio