arXiv subjects

M. L. Solovyov

Publications and source records attributed to M. L. Solovyov.

5 recordsLinked to original sources

arXiv2025

Reconstruction of the dark matter density profile from cosmic positron anomaly data

In this work we continue our investigations of the possibility of explanation of the positron anomaly (PA) in cosmic rays with the help of annihilating or decaying dark matter (DM) component by varying its space distribution. In the contrast of our previous studies, where we first assumed some specific spatial distribution of DM component and looked at how it agrees with data, here we solve, in some sense, the inverse problem: we search for distribution, in a mathematical way, which satisfies observational data. A unique algorithm has been implemented which, using linear algebra and adaptive grid methods, adjusts distribution to the data. It allows telling in principle whether or not is possible to solve PA problem by variation of spatial distribution of DM sources. A positive result has been formally obtained. A class of solutions can be identified. Though the distributions obtained at the chosen injection spectra may seem slightly realistic, nonetheless it demonstrates a quite powerful possibility in explaining PA that could be realized in more realistic models.

astro-ph.HE↗

arXiv2022

Hot primordial regions with anomalous hydrogenless chemical composition

We study primordial nucleosynthesis in hypothetical hot regions that could be formed by the primordial density inhomogeneities. It is shown that the regions survived up to the present times acquire an abnormally high metallicity. This conclusion holds in wide range of initial parameters of such regions. We considered the thermonuclear reaction rates and estimated abundances of deuterium and helium-3 and -4 inside these areas. It has been established that all baryons tend to form helium-4, which is the thermonuclear link in the chain of formation of heavier elements.

astro-ph.CO↗

arXiv2020

The "Dark disk" model in the light of DAMPE experiment

There are a lot of models considering the Dark Matter (DM) to be the origin of cosmic ray (CR) positron excess. However, they face an obstacle in the form of gamma-rays. Simple DM models tend to overproduce gamma-rays, leading to contradiction with isotropic gamma-ray background (IGRB). The < > model has been proposed to alleviate this contradiction. This work considers results of DAMPE experiment in the framework of the disk model. It is obtained that such a framework allows improving data fit considerably.

astro-ph.HE↗

arXiv2019

Indirect effects of dark matter

Here we briefly review possible indirect effects of dark matter (DM) of the Universe. It includes effects in cosmic rays (CR): first of all, the positron excess at $\sim$ 500 GeV and possible electron-positron excess at 1-1.5 TeV. We tell that the main and least model-dependent constraint on such possible interpretation of CR effects goes from gamma-ray background. Even ordinary $e^+e^-$ mode of DM decay or annihilation produces prompt photons (FSR) so much that leads to contradiction with data on cosmic gamma-rays. We present our attempts to possibly avoid gamma-ray constraint. They concern peculiarities of both space distribution of DM and their physics. The latter involves complications of decay/annihilation modes of DM, modifications of Lagrangian of DM-ordinary matter interaction, and inclusion of mode with identical fermions in final state. In this way, no possibilities to suppress were found except, possibly, mode with identical fermions. While the case of spatial distribution variation allows achieving consistency between different data. Also we consider stable form of dark matter which can interact with baryons. We show which constraint such DM candidate can get from damping effect in plasma during large scale structure formation in comparison with other existing constraints.

hep-ph↗

arXiv2018

Development of dark disk model of positron anomaly origin

Dark disk model could be a remedy for dark matter (DM) explanation of positron anomaly (PA) in cosmic rays (CR). The main difficulty in PA explanation relates to cosmic gamma-radiation which is inevitably produced in DM annihilation or decay leading to tension with respective observation data. Introduction of "active" (producing CR) DM component concentrating in galactic disk alleviates this tension. Earlier we considered two-lepton modes, with branching ratios being chosen to fit in the best way all the observation data. Here we considered, in framework of the same dark disk model, two cases: two-body final state annihilation and four-body one, and in each case a quark mode is added to the leptonic ones. It is shown that 4-body mode case is a little better than 2-body one from viewpoint of quality of observation data description at the fixed all other parameters (of CR propagation, background, disk height). The values of DM particle mass around 350 GeV and 500 GeV are more favourable for 2- and 4-body modes respectively. Higher values would improve description of data on positrons only but accounting for data on gamma-radiation prevents it because of unwanted more abundant high-energy gamma production. Inclusion of the quark modes improves a little fitting data in both 4- and 2-body mode cases, contrary to naive expectations. In fact, quark mode has a bigger gammas yield than that of most gamma-productive leptonic mode~--- tau, but they are softer due to bigger final state hadron multiplicity.

astro-ph.HE↗