Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userEvolution of Universe to the present inert phase
180
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
We assume that current state of the Universe can be described by the Inert Doublet Model, containing two scalar doublets, one of which is responsible for EWSB and masses of particles and the second one having no couplings to fermions and being responsible for dark matter. We consider possible evolutions of the Universe to this state during cooling down of the Universe after inflation. We found that in the past Universe could pass through phase states having no DM candidate. In the evolution via such states in addition to a possible EWSB phase transition (2-nd order) the Universe sustained one 1-st order phase transition or two phase transitions of the 2-nd order.
rate research
Read More
The evolution of the Universe is the ultimate laboratory to study fundamental physics across energy scales that span about 25 orders of magnitude: from the grand unification scale through particle and nuclear physics scales down to the scale of atomic physics. The standard models of cosmology and particle physics provide the basic understanding of the early and present Universe and predict a series of phase transitions that occurred in succession during the expansion and cooling history of the Universe. We survey these phase transitions, highlighting the equilibrium and non-equilibrium effects as well as their observational and cosmological consequences. We discuss the current theoretical and experimental programs to study phase transitions in QCD and nuclear matter in accelerators along with the new results on novel states of matter as well as on multi- fragmentation in nuclear matter. A critical assessment of similarities and differences between the conditions in the early universe and those in ultra- relativistic heavy ion collisions is presented. Cosmological observations and accelerator experiments are converging towards an unprecedented understanding of the early and present Universe.
In this work an update of the cosmological role and place of the chiral tensor particles in the Universe history is provided. We discuss an extended model with chiral tensor particles. The influence of these particles on the early Universe evolution is studied. Namely, the increase of the Universe expansion rate caused by the additional particles in this extended model is calculated, their characteristic interactions with the particles of the hot Universe plasma are studied and the corresponding times of their creation, scattering, annihilation and decay are estimated for accepted values of their masses and couplings, based on the recent experimental constraints. The period of abundant presence of these particles in the Universe evolution is determined.
A period of slow contraction with equation of state w > 1, known as an ekpyrotic phase, has been shown to flatten and smooth the universe if it begins the phase with small perturbations. In this paper, we explore how robust and powerful the ekpyrotic smoothing mechanism is by beginning with highly inhomogeneous and anisotropic initial conditions and numerically solving for the subsequent evolution of the universe. Our studies, based on a universe with gravity plus a scalar field with a negative exponential potential, show that some regions become homogeneous and isotropic while others exhibit inhomogeneous and anisotropic behavior in which the scalar field behaves like a fluid with w=1. We find that the ekpyrotic smoothing mechanism is robust in the sense that the ratio of the proper volume of the smooth to non-smooth region grows exponentially fast along time slices of constant mean curvature.
We introduce one pair of inert Higgs doublets {H_d, H_u} and singlets {N^c, N}, and consider their couplings with the Higgs doublets of the minimal supersymmetric standard model (MSSM), W supset y_N N^c h_u H_d + y_N N h_d H_u. We assign extra U(1)_{Z} gauge charges only to the extra vector-like superfields, and so all the MSSM superfields remain neutral under the new U(1)_{Z}. They can be an extension of the lambda term, W supset lambda S h_u h_d in the next-to-MSSM (NMSSM). Due to the U(1)_{Z}, the maximally allowed low energy value of y_N can be lifted up to 0.85, avoiding a Landau-pole (LP) below the grand unification scale. Such colorless vector-like superfields remarkably enhance the radiative MSSM Higgs mass particularly for large tanbeta through the y_N term and the corresponding holomorphic soft term. As a result, the lower bound of lambda and the upper bound of tanbeta can be relaxed to disappear from the restricted parameter space of the original NMSSM, 0.6 < lambda < 0.7 and 1< tanbeta < 3. Thus, the valid parameter space significantly expands up to 0 < lambda < 0.7, 0 < y_N < 0.85, and 2 < tanbeta < 50, evading the LP problem and also explaining the 126 GeV Higgs mass naturally.
We propose a two-loop induced Zee-Babu type neutrino mass model at the TeV scale. Although there is no dark matter candidate in the original Zee-Babu model, that is contained in our model by introducing an unbroken discrete $Z_2$ symmetry. The discrepancy between the experimental value of the muon anomalous magnetic moment (muon $g-2$) and its prediction in the standard model can be explained by contributions from additional vector-like charged-leptons which are necessary to give non-zero neutrino masses. The mass of vector-like leptons to be slightly above 300 GeV is favored and allowed from the muon $g-2$ and the current LHC data. We find that from the structure of neutrino mass matrix, doubly-charged scalar bosons in our model can mainly decay into the same-sign and same-flavour dilepton plus missing transverse momentum. By measuring an excess of these events at the LHC, our model can be distinguished from the other models including doubly-charged scalar bosons.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
