Minimal inflationary cosmologies and production of heavy dark matter (original) (raw)
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Minimal inflationary cosmologies and constraints on reheating
arXiv: Cosmology and Nongalactic Astrophysics, 2016
With the growing consensus on simple power law inflation models not being favored by the PLANCK observation, dynamics for the non-standard form of the inflaton potential gain significant interest in the recent past. In this paper, we analyze in great detail classes of phenomenologically motivated inflationary models with non-polynomial potential which are the generalization of the potential introduced in \cite{mhiggs}. After the end of inflation, inflaton field will coherently oscillate around its minimum. Depending upon the initial amplitude of the oscillation and coupling parameters standard parametric resonance phenomena will occur. Therefore, we will study how the inflationary model parameters play an important role in understanding the resonant structure of our model under study. Subsequently, the universe will go through the perturbative reheating phase. However, without any specific model consideration, we further study the constraints on our models based on model independent...
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Journal of Cosmology and Astroparticle Physics, 2006
We present a complete particle physics model that explains three major problems of modern cosmology: inflation, dark matter and dark energy, and also gives a mechanism for leptogenesis. The model has a new gauge group SU (2)Z that grows strong at a scale Λ ∼ 10 −3 eV. We focus on the inflationary aspects of the model. Inflation occurs with a Coleman-Weinberg potential at a low scale, down to ∼ 6 × 10 5 GeV, being compatible with observational data.
Vector dark matter production from inflation with symmetry breaking
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We present a scenario of vector dark matter production from symmetry breaking at the end of inflation. In this model, the accumulated energy density associated with the quantum fluctuations of the dark photon accounts for the present energy density of dark matter. The inflaton is a real scalar field while a heavy complex scalar field, such as the waterfall of hybrid inflation, is charged under the dark gauge field. After the heavy field becomes tachyonic at the end of inflation, rolling rapidly toward its global minimum, the dark photon acquires mass via the Higgs mechanism. To prevent the decay of the vector field energy density during inflation, we introduce couplings between the inflaton and the gauge field such that the energy is pumped to the dark sector. The setup can generate the observed dark matter abundance for a wide range of the dark photon's mass and with the reheat temperature around 10 12 GeV. The model predicts the formation of cosmic strings at the end of inflation with the tensions which are consistent with the CMB upper bounds.
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Physics of the Dark Universe, 2019
We consider the CMB constrains on reheating and dark matter parameter space for a specific plateau type inflationary model. The plateau inflationary models which are currently most favored models from data can be well approximated by a potential of the form V (φ) ∝ φ n around φ = 0. This fact makes it possible to study the reheating phase with general inflaton equation of state in a viable cosmological scenario. In addition, following our recent work[1], we generalize the connection between reheating and the present CMB data and the dark matter parameter space for general inflaton equation of state parameter.
Minimal plateau inflationary cosmologies and constraints from reheating
Classical and Quantum Gravity, 2019
With the growing consensus on simple power law inflation models not being favored by the PLANCK observations, dynamics for the non-standard inflation gain significant interest in the recent past. In this paper, we analyze in detail a class of supergravity inspired phenomenological inflationary models with non-polynomial potential based on[1], and compare the model predictions with the currently most favored Starobinsky and its generalized α-attractor models in the (n s , r) plane constrained by PLANCK. Importantly for a wide range of parameter space, our model provides successful inflation in the sub-Planckian regime. We also have performed model independent analysis of reheating in terms of the effective equation of state parameter. In particular, we consider two stages of reheating dynamics with generalized inflaton equation of state in the initial and relativistic equation of state in the later phase. Finally, we show how our generalized reheating analysis constrains the inflation models under consideration.
In this work we introduce a new plateau-like inflationary model including a quadratic scalar potential coupled non-minimally to gravity. This potential has a dominant constant energy density at early times which can realize successful inflation. It also includes an infinitesimal non-zero term V0 responsible for explaining dark energy which causing the universe to expand accelerating at the late time. We show that this model predicts small tensor-to-scalar ratio of the order of r 0.01 which is fully consistent with Planck constraints. Using the lower and upper bounds on reheating temperature, we provide additional constraints on the non-minimal coupling parameter of the model. We also study the preheating stage predicted by this kind of potentials using numerical calculations.
Beyond the simplest inflationary cosmological models
Though predictions of the simplest inflationary cosmological models with cold dark matter, flat space and approximately flat initial spectrum of adiabatic perturbations are remarkably close to observational data, we have to go beyond them and to introduce new physics not yet discovered in laboratories to account for all data. Two extensions of these models which seem to be the most actual at present time are discussed. The first one is the possibility that we are living at the beginning of a new inflation-like era. Then classical cosmological tests, like the luminosity distance or the angular size of distant objects as functions of redshift, as well as the behaviour of density perturbations in a dustlike matter component including baryons as a function of redshift, can provide information sufficient for the unambiguous determination of an effective potential of a corresponding present inflaton scalar field. The second, unrelated extension is a possibility of brokenscale-invariant cosmological models which have localized steps or spikes in the primordial perturbation spectrum. These features can be produced by fast phase transitions in physical fields other than an inflaton field in the early Universe during inflation and not far from the end of it. At present, it seems that the only scale in the spectrum around which we might see something of this type is k = 0.05 h Mpc −1 .
The European Physical Journal C, 2017
In the present work, we study the consequences of considering a new family of single-field inflation models, called power-law plateau inflation, in the warm inflation framework. We consider the inflationary expansion is driven by a standard scalar field with a decay ratio having a generic power-law dependence with the scalar field φ and the temperature of the thermal bath T given by (φ, T) = C φ T a φ a−1. Assuming that our model evolves according to the strong dissipative regime, we study the background and perturbative dynamics, obtaining the most relevant inflationary observable as the scalar power spectrum, the scalar spectral index and its running and the tensor-toscalar ratio. The free parameters characterizing our model are constrained by considering the essential condition for warm inflation, the conditions for the model evolves according to the strong dissipative regime and the 2015 Planck results through the n s-r plane. For completeness, we study the predictions in the n s-dn s /d ln k plane. The model is consistent with a strong dissipative dynamics and predicts values for the tensor-to-scalar ratio and for the running of the scalar spectral index consistent with current bounds imposed by Planck and we conclude that the model is viable.
Advances in High Energy Physics
We investigate matter creation processes during the reheating period of the early Universe, by using the thermodynamic of open systems. The Universe is assumed to consist of the inflationary scalar field, which, through its decay, generates relativistic matter and pressureless dark matter. The inflationary scalar field transfers its energy to the newly created matter particles, with the field energy decreasing to near zero. The equations governing the irreversible matter creation are obtained by combining the thermodynamics description of the matter creation and the gravitational field equations. The role of the different inflationary scalar field potentials is analyzed by using analytical and numerical methods. The values of the energy densities of relativistic matter and dark matter reach their maximum when the Universe is reheated up to the reheating temperature, which is obtained as a function of the scalar field decay width, the scalar field particle mass, and the cosmological ...
Constraining inflationary dark matter in the luminogenesis model
Journal of Cosmology and Astroparticle Physics, 2015
Using renormalization-group flow and cosmological constraints on inflation models, we exploit a unique connection between cosmological inflation and the dynamical mass of dark matter particles in the luminogenesis model, a unification model with the gauge group SU (3) C × SU (6) × U (1) Y , which breaks to the Standard Model with an extra gauge group for dark matter when the inflaton rolls into the true vacuum. In this model, inflaton decay gives rise to dark matter, which in turn decays to luminous matter in the right proportion that agrees with cosmological data. Some attractive features of this model include self-interacting dark matter, which may resolve the problems of dwarf galaxy structures and dark matter cusps at the centers of galaxies.