Related papers: A Gravitino-rich Universe
We propose the gravitino dark matter in the gravity mediated supersymmetry breaking scenario. The mass hierarchies between the gravitino and other superparticles can be achieved by the nontrivial K\"ahler metric of the supersymmetry…
The impact of a kination-dominated phase generated by a quintessential exponential model on the thermal abundance of gravitinos and axinos is investigated. We find that their abundances become proportional to the transition temperature from…
The Standard Model of particle physics fails to explain the important pieces in the standard cosmology, such as inflation, baryogenesis, and dark matter of the Universe. We consider the possibility that the sector to generate small neutrino…
Astrophysical and cosmological arguments and observations give us the most restrictive constraints on neutrino masses, electromagnetic couplings, and other properties. Conversely, massive neutrinos would contribute to the cosmic dark-matter…
We revisit Higgs inflation in the framework of a minimal extension of the Standard Model gauge symmetry by a $U(1)_{B-L}$ factor. Various aspects are taken into account with particular focus on the role of the supersymmetry breaking (SUSY)…
We present an inflationary scenario based on a phenomenologically viable model with direct gauge mediation of low-scale supersymmetry breaking. Inflation can occur in the supersymmetry-breaking hidden sector. Although the reheating…
In this paper we study the interplay between the recently proposed F-theory GUTs and cosmology. Despite the fact that the parameter range for F-theory GUT models is very narrow, we find that F-theory GUTs beautifully satisfy most…
A very simple way to obtain comparable baryon and DM densities in the early Universe is through their contemporary production from the out-of-equilibrium decay of a mother particle, if both populations are suppressed by comparably small…
Supersymmetric theories with gravitino dark matter generally do not allow the high reheating temperature required by thermal leptogenesis without running afoul of relic abundance or big bang nucleosynthesis constraints. We report on a…
We consider the simplest possibility for a model of particle dark matter in which dark matter has only gravitational interaction with the standard model sector. Even in such a case, it is known that the gravitational particle production in…
Starting with the vacuum fluctuation, it is known that gravitinos will be created just after inflation, with number density $\sim 10^{-2}M^3$ where $M$ is the mass of the inflaton. Here, we argue that creation may be expected to continue,…
The identity of dark matter is one of the greatest puzzles of our Universe. Its solution may be associated with supersymmetry which is a fundamental space-time symmetry that has not been verified experimentally so far. In many…
It has been widely known that bino-like dark matter in supersymmetric theories suffers from over-production. The situation can be improved if the gluino or wino has a mass of O(10) GeV heavier than the bino, sufficiently reducing the bino…
Dark matter could have an electroweak origin, yet communicate with the visible sector exclusively through gravitational interactions. In a set-up addressing the hierarchy problem, we propose a new dark matter scenario where gravitational…
Within the framework of an explicit dynamical model, in which we calculate the radiatively-corrected, tree-level potential that sets up inflation, we show that the inflaton can be a significant part of dark matter today. We exhibit…
We show that a Majorana heavy neutrino with a mass O(100TeV) is a good candidate particle for cold dark matter. It can be responsible for the majority of the cosmological diffuse photon background owing to lifetime of the order of…
In this paper a hypothesis is considered, in which neutrinos and other weakly interacting particles play a fundamental role in Universe. In addition the Newton gravitational constant $G_N$ and the Hubble constant $H$ are interpreted as…
We present a full one-loop calculation of the gravitino thermal production rate, beyond the so-called hard thermal loop approximation, using the corresponding thermal spectral functions in numerical form on both sides of the light cone.…
Scalar-tensor theories of gravity that embrace conformal coupling to the scalar curvature are the focal point of cosmology on discussions of inflation and late-time accelerating universe. Although there exists a stringent nucleo-synthesis…
The decay of a false vacuum of unbroken B-L symmetry is an intriguing and testable mechanism to generate the initial conditions of the hot early universe. If B-L is broken at the grand unification scale, the false vacuum phase yields hybrid…