Related papers: Graviton Cosmology in Universal Extra Dimensions
In supersymmetric models of warm inflation, the large temperature of the radiation bath produced by the dissipative motion of the inflaton field may induce a significant thermal abundance of potentially dangerous gravitinos. While previous…
Recent studies of the cosmic microwave background, large scale structure, and big bang nucleosynthesis (BBN) show trends towards extra radiation. Within the framework of supersymmetric hadronic axion models, we explore two…
We study the production of spin 1/2 gravitinos in a thermal Universe. Taking into account supersymmetry breaking due to the finite thermal energy density of the Universe, there is a large enhancement in the cross section of production of…
We consider the production of matter and radiation during reheating after inflation, restricting our attention solely to gravitational interactions. Processes considered are the exchange of a graviton, $h_{\mu \nu}$, involved in the…
The observed low-energy values of the $SU(3)\times SU(2)\times U(1)$ gauge couplings, extrapolated via the minimal Standard Model Renormalization Group evolution, hint at the exciting possibility of a Grand Unified Theory (GUT) at $M_U \sim…
We discuss the signatures, at the LHC, of the (1,0)-th Kaluza-Klein (KK) gluon and quarks in the framework of the two universal extra dimensional (2UED) model. Once produced, these particles typically suffer a cascade of decays terminating…
In String theory realizations of inflation, the end point of inflation is often brane-anti brane annihilation. We consider the processes of reheating of the Standard Model universe after brane inflation. We identify the channels of inflaton…
We show that the gravitino-overproduction problem is prevalent among inflation models in supergravity. An inflaton field \phi generically acquires (effective) non-vanishing auxiliary field G_\phi, if the K\"ahler potential is non-minimal.…
One proposed solution of the moduli problem of string cosmology requires that the moduli are quite heavy, their decays reheating the universe to temperatures above the scale of nucleosynthesis. In many of these scenarios, the moduli are…
The framework of a warped extra dimension with the Standard Model (SM) fields propagating in it is a very well-motivated extension of the SM since it can address both the Planck-weak and flavor hierarchy problems of the SM. We consider…
In the framework of quantum gravity propagating in large extra dimensions, the effects of virtual Kaluza-Klein gravitons on the imaginary part of the amplitude of the process e+ e- --> f f-bar are analyzed at the Z-pole. Notably, the…
By invoking small extra dimensions as a good energy bearer, a new scenario for understanding the origin of ultrahigh-energy cosmic rays (UHECRs), from both the bottom-up and the top-down viewpoints, is proposed. We explore the possibility…
In the framework of the large extra dimensions (LED) model, we investigate the effects induced by the Kaluza-Klein (KK) gravitons up to the QCD next-to-leading order (NLO) on the $W$-pair production followed by a subsequential $W$-decay at…
In supergravity theories, a natural possibility is that neutralinos or sleptons freeze out at their thermal relic density, but then decay to gravitinos after about a year. The resulting gravitinos are then superWIMPs --…
If large extra dimensions exist in nature, supernova (SN) cores will emit large fluxes of Kaluza-Klein gravitons, producing a cosmic background of these particles with energies and masses up to about 100 MeV. Radiative decays then give rise…
In five-dimensional universal extra-dimensional models compactified on an $S^1/Z_2$ orbifold four-dimensional kinetic terms are allowed at the two fixed points. If these terms are unequal then Kaluza-Klein (KK) parity is broken. Within such…
Here we study the essence of $f(R,T)$ gravitation theory in five dimensional Universe and see the role of dark energy in the form of wet dark fluid in such a Universe. It is found that the dark energy is not exaggerated in contributing to…
The non-thermal production of dark matter (DM) usually requires very tiny couplings of the dark sector with the visible sector and therefore is notoriously challenging to hunt in laboratory experiments. Here we propose a novel pathway to…
We report on a search for large extra dimensions in a data sample of approximately 1 fb^{-1} of ppbar collisions at sqrt(s) = 1.96 TeV. We investigate Kaluza-Klein graviton production with a photon and missing transverse energy in the final…
The prospect of large extra dimensions and an effective theory of gravity at around a TeV has interesting experimental consequences. In these models, the Kaluza-Klein modes interact with Standard Model particles and these interactions lead…