Possibility of hypothetical stable micro black hole production at future 100 TeV collider

We study the phenomenology of TeV-scale black holes predicted in theories with large extra dimensions, under the further assumption that they are absolutely stable. Our goal is to present an exhaustive analysis of safety of the proposed 100 TeV collider, as it was done in the case of the LHC. We consider the theories with different number of extra dimensions and identify those for which a possible accretion to macroscopic size would have timescales shorter than the lifetime of the Solar system. We calculate the cross sections of the black hole production at the proposed 100 TeV collider, the fraction of the black holes trapped inside the Earth and the resulting rate of capture inside the Earth via an improved method. We study the astrophysical consequences of stable micro black holes existence, in particular its influence on the stability of white dwarfs and neutron stars. We obtain constraints for the previously unexplored range of higher-dimensional Planck mass values. Several astrophysical scenarios of the micro black hole production, which were not considered before, are taken into account. Finally, using the astrophysical constraints we consider the implications for future 100 TeV terrestrial experiments. We exclude the possibility of the charged stable micro black holes production.Comment: 11 pages, 8 figures, accepted for publication in EPJ

Interfering Doorway States and Giant Resonances. II: Transition Strengths

The mixing of the doorway components of a giant resonance (GR) due to the interaction via common decay channels influences significantly the distribution of the multipole strength and the energy spectrum of the decay products of the GR. The concept of the partial widths of a GR becomes ambiguous when the mixing is strong. In this case, the partial widths determined in terms of the $K$- and $S$-matrices must be distinguished. The photoemission turns out to be most sensitive to the overlapping of the doorway states. At high excitation energies, the interference between the doorway states leads to a restructuring towards lower energies and apparent quenching of the dipole strength.Comment: 17 pages, LaTeX, 5 figures as JPEG, to appear in PRC (July 1997

Between Barbarism and Progress: Enlightenment Historical Writings on a Major Conflict in Russian History

Received 11 November 2019. Accepted 20 December 2019. Published online 6 January 2020.The dichotomy of barbarism and progress has long been a focal point for the discussions about Russia’s past and present. The discourse on Russian barbarism had been known in Europe since at least 16th century, but Enlightenment thinkers gave it a new shape by juxtaposing the ancient conception of barbarism with the rather modern idea of progress. In this article, Enlightenment historical writings are examined; the focus is on the question of how Russian history was studied in order to find signs of barbarism and the different guises of progress. The primary sources for the article are mainly Russian historical writings; however, relations and interactions between Russian and European intellectuals, as well as intellectual exchange and influence, are also noted. As there were no word “civilization” in 18th-century Russian, enlightenment was deemed by Russian thinkers as the antipode to barbarism. It is concluded that most Enlightenment writers saw Christianization as a step forward from barbarism in Russian history. Parallels between Russia and Scandinavia as they were drawn by August Schlözer are also analyzed. The article shows how the idea of conflict between barbarism and progress altered the understanding of Russian history in the Enlightenment.This work was supported by the Russian Science Foundation under the grant No. 18-18-00216