Renormalization group in the theory of turbulence: Three-loop approximation as <Emphasis Type="Italic">d</Emphasis> → ∞

We use the renormalization group method to study the stochastic Navier-Stokes equation with a random force correlator of the form k ^4−d−2ɛ in a d-dimensional space in connection with the problem of constructing a 1/d-expansion and going beyond the framework of the standard ɛ-expansion in the theory of fully developed hydrodynamic turbulence. We find a sharp decrease in the number of diagrams of the perturbation theory for the Green’s function in the large-d limit and develop a technique for calculating the diagrams analytically. We calculate the basic ingredients of the renormalization group approach (renormalization constant, β-function, fixed-point coordinates, and ultraviolet correction index ω) up to the order ɛ ³ (three-loop approximation). We use the obtained results to propose hypothetical exact expressions (i.e., not in the form of ɛ-expansions) for the fixed-point coordinate and the index ω. __________ Translated from Teoreticheskaya i Matematicheskaya Fizika, Vol. 158, No. 3, pp. 460–477, March, 2009.     

Measurements of the integrated muon intensity at large zenith angles

Precision measurements of the zenith-angle distributions of muons in the range 61°–89° are performed using the DECOR coordinate detector. The total number of selected events is more than 20 million. The dependence of the integrated muon intensity on the zenith angle is determined for several threshold energies in the range from 1.7 to 7.2. GeV. The experimental results in these ranges of zenith angles and threshold energies are obtained for the first time. It is demonstrated that the dependence of the integrated muon intensity on the zenith angle is adequately described by a simple analytical relationship.     

Experiments on small-size fast critical fuel assemblies at the AKSAMIT facility and their use for development of computational models

Small-size fast critical assemblies with highly enriched fuel at the AKSAMIT facility are described in detail. Computational models of the critical assemblies at room temperature are given. The calculation results for the critical parameters are compared with the experimental data. A good agreement between the calculations and the experimental data is shown. The physical models developed for the critical assemblies, as well as the experimental results, can be applied to verify various codes intended for calculation of the neutronic characteristics of small-size fast nuclear reactors. For these experiments, the results computed using the codes of the MCU family show a high quality of the neutron data and of the physical models used.     

Study of cascade showers generated by near-horizontal muons in the water Cherenkov detector with a dense array of optical modules

The method for reconstructing the cascade curve by the Cherenkov radiation in water of the NEVOD detector with a dense spatial array of optical modules is discussed. Cascades are generated by near-horizontal muons which are separated by the DECOR coordinate detector. The cascade curves and the cascade energy spectrum measured in an ～8000-hour measurement series are presented.     

Investigating the energy, angular, and temporal characteristics of forbush effects registered by the URAGAN muon hodoscope

The results from analyzing variations in the flux of cosmic ray muons during Forbush effects (FEs) registered by the URAGAN muon hodoscope over the period 2005–2009 are presented. The dependences of the amplitudes for reductions in the intensity of the cosmic ray muon flux on the energy of primary particles in energy ranges higher than 10 GeV were obtained. Their changes upon different phases of Forbush effect development were investigated. The local anisotropy vectors were calculated on the basis of spatial-angular variations in the muon flux. Correlations between the parameters of physical properties in the near heloiosphere related to the Forbush effects and the characteristics of muon flux variations were analyzed.     

Critical behavior of the <Emphasis Type="Italic">O</Emphasis>(<Emphasis Type="Italic">n</Emphasis>) <Emphasis Type="Italic">ϕ</Emphasis><Superscript>4</Superscript> model with an antisymmetric tensor order parameter: Three-loop approximation

We consider the critical behavior of the O(n)-symmetric model of the ? ⁴ type with an antisymmetric tensor order parameter. According to a previous study of the one-loop approximation in the quantum field theory renormalization group, there is an IR-attractive fixed point in the model, and IR scaling with universal indices hence applies. Using a more specific analysis based on three-loop calculations of the renormalization-group functions and Borel conformal summation, we show that the IR behavior is in fact governed by another fixed point of the renormalization-group equations and the model therefore belongs to a different universality class than the one suggested by the simplest one-loop approximation. Nevertheless, the validity of the obtained results remains a subject for discussion.     

Physical states of aqueous solutions of oxyethylated glycerol with polymerization degree of n=30 at temperatures lower than 283 K

A binary system water-oxyethylated glycerol with polymerization degree of n=30 (OEGn=30) is studied over the concentration range of 0-100% (w/w) and the temperature range of 123-283 K by differential scanning calorimetry (DSC). A phase diagram of this system is constructed at the average cooling rate of 200 K-1 per min and the warming rate of 0.5 K-1 per min. Ice crystallization occurs and 70% (w/w) unfrozen residues remain during cooling in the OEGn=30 concentration range of 0-45% (w/w). The system hardens in the amorphous state during cooling and ice crystallization occurs during warming in the range of 46-62% (w/w). Crystallization is observed neither during the cooling nor the subsequent warming in the range of 63-74% (w/w). OEGn=30 crystallization occurs in the range of 75-100% (w/w). Each OEGn=30 molecule can strongly bind to 48 water molecules. In parallel with dsc study, the water-OEGn=30 system is investigated by cryomicroscopy in the temperature range of 173-283 K. Cryomicrographs of the solidified solutions representing each of the four concentration bands mentioned above are given.     

New detecting system of the NEVOD Cherenkov water detector

A new detecting system of the NEVOD Cherenkov water detector is described, whose development implies replacement of photomultipliers in quasispherical modules of the existing three-dimensional network by low-noise FEU-200 photomultipliers, their dynamic range expansion with the purpose to study events with energies above 10¹⁷ eV, the transition to the cluster structure principle, and the possibility of operating in the hodoscopic mode.