In modern high-energy physics, based on the principles and methods of quantum field theory, the Standard Model (SM) has been developed and tested with high accuracy in many experiments, which at the moment contains scientific knowledge about the structure of the microworld. However, there are a number of theoretical problems and confirmed observed phenomena in the structure and evolution of the Universe that cannot be explained within the framework of this model. One of such phenomena is the obvious existence in the Universe of a special type of matter, the so-called hidden mass (or Dark Matter), which manifests itself mainly in the gravitational effect on astronomical objects.

“The physics of Dark Matter can only be understood within the framework of extensions of the Standard Model. But it is possible to construct generalizations of the Standard Model mathematically accurately in more than one way; there are many options to add new objects to the already known particles of the Standard Model. Currently, we are in constant active search, developing and analyzing various scenarios of SM expansion, predicting observable and measurable effects in which the mysterious nature of elusive particles of hidden mass will manifest, "said Vitaly Beilin, a leading researcher at the theoretical physics department of the Scientific Research Institute of Physics, SFedU.

According to scientists, studies of original models of physics of the hidden mass of the Universe, which require considering phenomena on cosmological scales using the methods of quantum field theory and modern astrophysics, are carried out within the framework of a synthetic approach - cosmomicrophysics.

“In our works, we have obtained a generalization of the complexity coefficient for static spherically symmetric self-gravitating structures in extended gravity models. For a locally anisotropic spherical distribution of matter, the field equations and conservation laws are determined. It is shown that the system can have a zero complexity coefficient if the effects of energy density inhomogeneity and pressure anisotropy neutralize the influence of each other, ”shared the head of the group, chief researcher at the Research Institute of Physics of the SFedU Maxim Khlopov.

A group of theoreticians from the Scientific Research Institute of Physics of the Southern Federal University showed that in the original model of the SM expansion by additional heavy fermions, hyperquarks, they developed, Dark Matter can be described as two-component, consisting of heavy particles interacting in different ways with ordinary matter, including high-energy cosmic rays. Scientists have also proposed a mechanism to delay the evaporation of primordial black holes (PBHs), so that their evaporation is the main source of the observed cosmic gamma background. At the final stage of

evaporation, these PBHs can be a source of cosmic rays and ultrahigh-energy gamma quanta, which makes it possible to verify their existence.

Our physicists have proposed a model of strongly interacting heavy compound carriers of hidden mass, consisting of ordinary and so-called singlet heavy quarks. A detailed analysis of the structure and specific interactions of such objects with ordinary matter has shown the presence of excited states in such composite objects, due to which a possible new observed effect is the appearance of a weak low-energy glow of the galactic DM halo. As Vladimir Kuksa, leading researcher of the Department of Theoretical Physics of the Scientific Research Institute of Physics of the Southern Federal University, explained, the low-energy radiation recently discovered on the XENON1T underground detector can also be a manifestation of this kind of Dark Matter.

New results of physicists from the Scientific Research Institute of Physics SFedU published in high-ranking journals (Axioms, Mon. Not. Roy. Astr. Soc., Symmetry V.12 (4), Symmetry, V. 12 (5) and Universe V.6 (10)) are presented in reports of international conferences (XXIII Int. Workshop “What Comes Beyond the Standard Models?”, Bled, Slovenia, 2020; The 4th Zeldovich Memorial Virtual Meeting, International Center for Relativistic Astrophysics Network and National Academy of Sciences of Belarus; 5th International Conference on Particle Physics and Astrophysics, dedicated 90th anniversary of BADolgoshein, NRNU, Moscow).