ترغب بنشر مسار تعليمي؟ اضغط هنا

Cosmological Constraints on Chiral Tensor Particles

247   0   0.0 ( 0 )
 نشر من قبل D. P. Kirilova
 تاريخ النشر 2019
  مجال البحث فيزياء
والبحث باللغة English




اسأل ChatGPT حول البحث

We discuss an extended model with chiral tensor particles in the Universe. Their direct influence on the Universe dynamics and their characteristic interactions in the hot Universe plasma, considered in previous publications, are briefly reviewed. A short discussion on the contemporary cosmological bounds on effective number of the relativistic degrees of freedom is provided. Cosmological constraints on the tensor particles interactions strength are obtained, corresponding to different cosmological bounds on the relativistic degrees of freedom and for different assumptions about right handed neutrinos.

قيم البحث

اقرأ أيضاً

Axion-like particles with masses in the keV-GeV range have a profound impact on the cosmological evolution of our Universe, in particular on the abundance of light elements produced during Big Bang Nucleosynthesis. The resulting limits are complement ary to searches in the laboratory and provide valuable additional information regarding the validity of a given point in parameter space. A potential drawback is that altering the cosmological history may potentially weaken or even fully invalidate these bounds. The main objective of this article is therefore to evaluate the robustness of cosmological constraints on axion-like particles in the keV-GeV region, allowing for various additional effects which may weaken the bounds of the standard scenario. Employing the latest determinations of the primordial abundances as well as information from the cosmic microwave background we find that while bounds can indeed be weakened, very relevant robust constraints remain.
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.
83 - O. Sergijenko 2017
We constrain the contribution of tensor-mode perturbations with free $n_t$ in the models with dynamical dark energy with the barotropic equation of state using Planck-2015 data on CMB anisotropy, polarization and lensing, BICEP2/Keck Array data on B- mode polarization, power spectrum of galaxies from WiggleZ and SN Ia data from the JLA compilation. We also investigate the uncertainties of reconstructed potential of the scalar field dark energy.
We present cosmological constraints on the scalar-tensor theory of gravity by analyzing the angular power spectrum data of the cosmic microwave background obtained from the Planck 2015 results together with the baryon acoustic oscillations (BAO) data . We find that the inclusion of the BAO data improves the constraints on the time variation of the effective gravitational constant by more than $10%$, that is, the time variation of the effective gravitational constant between the recombination and the present epochs is constrained as $G_{rm rec}/G_0-1 <1.9times 10^{-3} (95.45% {rm C.L.})$ and $G_{rm rec}/G_0-1 <5.5times 10^{-3} (99.99 % {rm C.L.})$. We also discuss the dependence of the constraints on the choice of the prior.
We discuss several physical constraints imposed on elasticity parameters of a transversely isotropic (TI) tensor. There are three types of restrictions we investigate; a fundamental one of stability conditions, and two additional ones, commonly consi dered in seismology. The first commonly considered restriction comes from an assumption of a wave with a greater speed in the horizontal than vertical direction. The second constitute the assumption that quasi-P wave is faster than quasi-S waves. We show several numerical examples to examine how these restrictions affect a TI tensor with known values of certain elasticity constants that could be acquired from the vertical or horizontal measurements.
التعليقات
جاري جلب التعليقات جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
mircosoft-partner

هل ترغب بارسال اشعارات عن اخر التحديثات في شمرا-اكاديميا