Selective Reflection Spectroscopy at the Interface between a Calcium Fluoride Window and Cs Vapour

A special vapour cell has been built, that allows the measurement of the atom-surface van der Waals interaction exerted by a CaF2 window at the interface with Cs vapour. Mechanical and thermal fragility of fluoride windows make common designs of vapour cells unpractical, so that we have developed an all-sapphire sealed cell with an internal CaF2 window. Although impurities were accidentally introduced when filling-up the prototype cell, leading to a line-broadening and shift, the selective reflection spectrum on the Cs D1 line (894 nm) makes apparent the weak van der Waals surface interaction. The uncertainties introduced by the effects of these impurities in the van der Waals measurement are nearly eliminated when comparing the selective reflection signal at the CaF2 interface of interest, and at a sapphire window of the same cell. The ratio of the interaction respectively exerted by a sapphire interface and a CaF2 interface is found to be 0.55 $\pm$ 0.25, in good agreement with the theoretical evaluation of ~0.67.Comment: soumis \`a Appl Phys B MS 4734

Two-particle angular correlations in the search for new physics at future e+e−e^+e^- colliders

The analysis of angular particle correlations can yield valuable insights into the initial state of matter in high-energy collisions, thereby potentially revealing the existence of Beyond the Standard Model scenarios such as Hidden Valley (HV). In this study, we focus on a QCD-like hidden sector with relatively massive HV quarks ($\lesssim 100$~GeV) which might enlarge and strengthen azimuthal correlations of final-state SM hadrons. In particular, we study the formation and possible observation of \textit{ridge-like} structures in the angular two-particle correlation function at future $e^+e^-$ colliders, with a much cleaner environment than in hadron colliders, such as the LHC.Comment: Talk presented at the International Workshop on Future Linear Colliders (LCWS 2023), 15-19 May 2023. C23-05-15.

Assessment and Calculation of Groundwater Reserves for Drinking Water Supply in Mountainous Areas of the Chechen Republic

This article is devoted to the urgent problem of drinking water supply in the mountainous regions of the Chechen Republic. The results of the assessment and calculation of groundwater reserves are presented. The article gives a brief assessment of the hydrogeological conditions of the study area, especially the complex of alluvial lower-upper Pleistocene sediments of the overdeepened river valleys, represented by boulder-pebble and boulder-rubbly formations with sand and sand-loamy aggregates. For inventory assessment and choice of a methodology of the reserves calculation in the Research Methods section, the hydrogeological conditions for the formation of groundwater are schematized in all the four study areas (Khimoyskiy, Shatoyskiy, Itum-Kalinskiy, Vedenskiy). On the basis of experimental field hydrogeological works, the calculation hydrogeological parameters necessary for the calculation of the groundwater reserves are determined (the main hydrogeological parameters on the estimated areas are given in the article, in the table 1). In the Methods section, the detailed justification of the scheme of placement of project wells is given (further the wells are supposed to be used as a water intake). For all the four areas – Khimoyskiy, Shatoyskiy, Itum-Kalinskiy and Vedenskiy the “strip aquifer” scheme is adopted as the calculation, limited by two parallel impermeable contours (the slopes of river valleys are composed of impermeable water-resistant bedrocks). In the Results section, all schemes, formulas and brief characteristics of each investigated area (the acreage, the necessary water demand, the type of project water intake) are given. For each area, an security assessment of the calculated reserves is given, which is confirmed by the balance method (all the calculations are given in the article). In conclusion of the article in table 03 the data on the reserves of fresh groundwater based on the results of prospecting-evaluation works of 01.06.2015 are given

Lorentz Invariance Violation induced time delays in GRBs in different cosmological models

Lorentz Invariance Violation (LIV) manifesting itself by energy dependent modification of standard relativistic dispersion relation has recently attracted a considerable attention. Ellis et al. previously investigated the energy dependent time offsets in different energy bands on a sample of gamma ray bursts and, assuming standard cosmological model, they found a weak indication for redshift dependence of time delays suggestive of LIV. Going beyond the $\Lambda$CDM cosmology we extend this analysis considering also four alternative models of dark energy (quintessence with constant and variable equation of state, Chaplygin gas and brane-world cosmology). It turns out that the effect noticed by Ellis et al. is also present in those models and is the strongest for quintessence with variable equation of state.Comment: 14 pages, 1 figur

Fragmentation of relativistic nuclei in peripheral interactions in nuclear track emulsion

The technique of nuclear track emulsions is used to explore the fragmentation of light relativistic nuclei down to the most peripheral interactions - nuclear "white" stars. A complete pattern of therelativistic dissociation of a $^8$B nucleus with target fragment accompaniment is presented. Relativistic dissociation $^{9}$Be$\to2\alpha$ is explored using significant statistics and a relative contribution of $^{8}$Be decays from 0$^+$ and 2$^+$ states is established. Target fragment accompaniments are shown for relativistic fragmentation $^{14}$N$\to$3He+H and $^{22}$Ne$\to$5He. The leading role of the electromagnetic dissociation on heavy nuclei with respect to break-ups on target protons is demonstrated in all these cases. It is possible to conclude that the peripheral dissociation of relativistic nuclei in nuclear track emulsion is a unique tool to study many-body systems composed of lightest nuclei and nucleons in the energy scale relevant for nuclear astrophysics.Comment: 15 pages, 4 figures, 4 tables, conference: Relativistic nuclear physics: from Nuclotron to LHC energies, Kiev, June 18-22, 200

Modified Dispersion Relations from the Renormalization Group of Gravity

We show that the running of gravitational couplings, together with a suitable identification of the renormalization group scale can give rise to modified dispersion relations for massive particles. This result seems to be compatible with both the frameworks of effective field theory with Lorentz invariance violation and deformed special relativity. The phenomenological consequences depend on which of the frameworks is assumed. We discuss the nature and strength of the available constraints for both cases and show that in the case of Lorentz invariance violation, the theory would be strongly constrained.Comment: revtex4, 9 pages, updated to match published versio

ЗАВИСИМОСТЬ ИСПОЛЬЗУЕМЫХ РЕСУРСОВ ОТ НЕЛИНЕЙНОСТИ ПРОИЗВОДСТВЕННОЙ ФУНКЦИИ

The inherent nonl inearity of production functions and loss of sensitivity generated by it and decreasing effectiveness are investigated in the framework of sensitivity theory. On this basis, the problem of optimization of resources is explored according to the criteria of benefits and costs, as well as the nonlinear nature of the central causation, which is characteristic of natural and artificial systems. The effects, reflecting these features, are spatio-temporal in nature and appear in engineering, economics, management. Attention to them is only increasing.Присущая производственным функциям нелинейность и порождаемые ею явления потери чувствительности и убывающей эффективности исследуются в рамках теории чувствительности. На этой основе рассматривается проблема оптимизации ресурсов с учетом критериев затрат и отдачи, а также нелинейной природы центральной причинной связи, свойственной естественным и искусственным системам. Отражающие эти особенности эффекты носят пространственно-временной характер и отражаются в технике, экономике, сфере управления. И внимание к ним только усиливается

Clustering in light nuclei in fragmentation above 1 A GeV

The relativistic invariant approach is applied to analyzing the 3.3 A GeV $^{22}$Ne fragmentation in a nuclear track emulsion. New results on few-body dissociations have been obtained from the emulsion exposures to 2.1 A GeV $^{14}$N and 1.2 A GeV $^{9}$Be nuclei. It can be asserted that the use of the invariant approach is an effective means of obtaining conclusions about the behavior of systems involving a few He nuclei at a relative energy close to 1 MeV per nucleon. The first observations of fragmentation of 1.2 A GeV $^{8}$B and $^{9}$C nuclei in emulsion are described. The presented results allow one to justify the development of few-body aspects of nuclear astrophysics.Comment: 7 pages, 8 figures, 3 tables, Nuclear Physics in Astrophysics-2, 16-20 May, 2005 (ATOMKI), Debrecen, Hungar

The model of particle production by strong external sources

Using some knowledge of multiplicity disributions for high energy reactions, it is possible to propose a simple analytical model of particle production by strong external sources. The model describes qualitatively most peculiar properties of the distributions. The generating function of the distribution varies so drastically as it can happen at phase transitions.Comment: 7 pages, no Figures, LATEX; Eq. (10) corrected, Eqs (25), (26) added, ref [20] corrected; Pisma v Zhetf 84, n5 (2006