相关论文: Ultra High Energy Cosmic Rays and Inflation
We give an overview over models in which cosmic rays above 1 EeV = 10**(18) eV are produced by the decay of supermassive "X" particles released from topological defects possibly created in cosmological phase transitions. We note that, for…
Cosmological inflation generates primordial density perturbations on all scales, including those far too small to contribute to the cosmic microwave background. At these scales, isolated ultracompact minihalos of dark matter can form well…
At the present moment, there is an unresolved problem in the physics of cosmic rays. The problem concerns the origin of the ultrahigh energy cosmic rays. One of the possible mechanisms of the particle's birth with such energy is bound to…
Cosmological inflation and topological defects have been considered for a long time, either in disagreement or in competition. On the one hand an inflationary era is required to solve the shortcomings of the hot big bang model, while on the…
The creation of ultra-light dark particles in the late-time FLRW spacetime provides a cosmological model in accordance with precise observational tests. The matter creation backreaction implies in this context a vacuum energy density…
A variant of hybrid inflation which is applicable in a wide class of supersymmetric grand unified models and reproduces the observed temperature perturbations of cosmic background radiation with natural values of the parameters is…
It is shown that the acceleration of particles by a powerful relativistic jet associated with the activity of a supermassive black hole in the Galactic center several million years ago may explain the observed cosmic ray spectrum at…
Origin of ultra high energy cosmic rays is an unsolved problem. Several proposals such as Z-burst, decay of super massive matter, susy particles as a primary, neutrino as a primary in extra dimension models exist in the literature which try…
In the present model, a unified picture of cosmology from early inflation to late acceleration is obtained from $ f(R)-$ gravity with non-linear terms $ R^2 $ and $ R^5 $ of scalar curvature $R$. It is discussed that elementary particles…
In the pre-reheating era, following cosmic inflation and preceding radiation domination, the energy density may be dominated by an oscillating massive scalar condensate, such as is the case for quadratic chaotic inflation. We have found in…
These lectures discuss the mysteries involving the production and extragalactic propagation of ultrahigh energy cosmic rays and suggested possible solutions.
These lecture notes intend to form a short pedagogical introduction to inflationary cosmology, highlighting selected areas of recent progress such as reheating and the theory of cosmological perturbations. Problems of principle for…
After cosmic inflation, the universe is cold and almost empty. Thus, the inflation field should decay to the particles for BBN through the so-called reheating process. Later, the matter-antimatter asymmetry and dark matter are produced. In…
We briefly review the main channels of gamma ray and neutrino production due to the propagation of ultra high energy cosmic rays. We show how the observations of these secondary radiations are of paramount importance in tagging mass…
The physics of Ultra High Energy Cosmic Rays will be reviewed, discussing the latest experimental results and theoretical models aiming at explaining the observations in terms of spectra, mass composition and possible sources. It will be…
We will discuss the main relevant aspects of the physics of ultra high energy cosmic rays. After a short recap of the experimental evidences, we will review theoretical models aiming at describing the sources of these extremely energetic…
We consider the cosmological production of fermionic dark matter during inflation and a post-inflationary radiation dominated era. This fermion \emph{only interacts gravitationally}, has a mass $m$ much smaller than the Hubble scale during…
A fundamental question that can be answered in the next decade is: WHAT IS THE ORIGIN OF THE HIGHEST ENERGY COSMIC PARTICLES? The discovery of the sources of the highest energy cosmic rays will reveal the workings of the most energetic…
We briefly discuss three aspects related to the origin of ultra-high energy cosmic rays (UHECRs) namely: 1) particle acceleration in astrophysical sources; 2) transition to an extragalactic origin; 3) spectrum and anisotropies at the…
We review the experimental evidences about flux and mass composition of ultra high energy cosmic rays in connection with theoretical scenarios concerning astrophysical sources. In this context, we also address the discussion about the…