Physics of Particles and Nuclei Letters最新文献

A hypothesis of neutron lifetime dependence on its helicity is proposed. It is shown that this effect contradicts with relativity principle and thus may be a test of it in a weak interaction. The numerical model of effect is built and the experiments for its measurement are considered as well as discussion and consequences.

Possibilities for formation of the charged pion field vortices in a rotating empty vessel (in vacuum) and in the rotating pion gas with a dynamically fixed particle number at zero temperature are studied within the (lambda {{left| phi right|}^{4}}) model. It is shown that in the former case at a rapid rotation a supervortex of a charged pion field can be formed. Important role played by the electric field is demonstrated. Field configurations in presence and absence of the pion self-interaction are found. Conditions for formation of the vortex lattice at the rotation of the charged pion gas at zero temperature are studied. Observational effects are discussed.

The effect of the combined use of protons at a dose of 3 Gy and 1-β-D-arabinofuranosylcytosine (Ara-C) on the physiological parameters of immunocompetent organs on the 90th day was studied: the weight of the spleen, thymus, total leukocyte count, and leukogram were examined. A significant decrease in thymus mass was established under the combined action of protons and Ara-C; a trend was observed in all experimental groups towards a decrease in spleen weight compared to the reference group. A statistically significant increase in the number of leukocytes in the “Ara-C” group was revealed, without differences in their types distribution during visual differentiated counting. It is concluded that further research of combined use of the DNA replication and Ara-C repair inhibitor and various types of ionizing radiation may be a promising way for extending the therapeutic capabilities of oncological practice.

Industrial effluents are often used to grow crops, including vegetables. Wastewaters contain not only organic matter and other nutrients but also heavy metals, which contribute to soil pollution and their further accumulation in vegetables. For this reason, a laboratory experiment was performed to assess zinc accumulation and translocation in the following chain: industrial effluents–soil–parts of radish (Raphanus sativus L.). The industrial effluents contained zinc in a concentration similar to its maximum permissible level in irrigation water (Effluent 1) and about 40 times higher than the established level (Effluent 2). Zinc concentrations in effluents, soil, and radish were determined by inductively coupled plasma optical emission spectrometry. The contamination factor, bioconcentration factor, translocation factor, and estimated daily intake of zinc were calculated. The antioxidant activity and the phenol content in radish biomass were also determined. The levels of zinc in different parts of radish ranged between 37.76 and 588 mg/kg dry weight and followed the order: non-edible roots of radish ≥ leaves ≥ edible roots. Zinc content in the edible and non-edible parts of radish irrigated with Effluent 2 was up to 5 times higher than the maximum permissible value of 117 mg/kg dry weight established by the Ministry of Health of the Russian Federation. The values of bioconcentration factors varied from 0.33 to 2.44 for radish roots, and the maximum bioaccumulation capacity was revealed for the control plants. According to this work, the values of the estimated daily intake of zinc were lower than the safe daily dietary intake established for zinc by World Health Organization.

The angular anisotropy of secondary neutrons in neutron emission spectra (NES) of even–even and even–odd target nuclei and in observed prompt fission neutron spectra (PFNS) of the even–odd ²³⁹Pu and ²³⁵U target nuclei is caused by the preequilibrium emission of neutrons in the reaction (n, nX)¹ and its effect on the prefission neutron spectrum from (n, xnf) reactions. In the case of PFNS, the average energy of (n, nf)¹ neutrons depends on the angle of emission with respect to the incident neutron beam θ; consequently, the fission cross section, the average number of prompt fission neutrons (PFN), and the total kinetic energy (TKE) of fission fragments also depend on θ. High sensitivity to emission of (n, xnf)¹ neutrons in the forward and backward hemispheres is predicted for the reaction ²³³U(n, F). Exclusive prefission neutron spectra from reactions ²³³U(n, xnf)^1,...x and exclusive neutron spectra from (n, nγ) and (n, xn)^1,...x are calculated within the Hauser–Feshbach formalism together with the cross sections for the (n,F) and (n,хn) reactions with allowance for the angular dependence of the first neutron emission (omega (theta )) in ²³³U(n, nX)¹. Calculated exclusive neutron spectra of ²³³U(n, xnf)^1,...x for θ ~ 90° agree with the consistent description of the observed ^{233, 232}U(n, F) fission cross sections for neutrons with an energy of E_n ~ 0.01–20 MeV. An approximation of the angular PFNS anisotropy (omega (theta )) obtained for ²³⁹Pu(n, F) and ²³⁵U(n, F) allows correlating the angular anisotropy of ²³³U(n, xnf)¹ neutrons with the contribution of the ²³³U(n, xnf) emission fission to the observed ²³³U(n, F) fission cross section. The ratio of average PFNS energies (leftlangle E rightrangle ) is obtained for forward and backward emission of (n, xnf)¹ in the reaction ²³³U(n, xnf), which is much larger than for the ²³⁹Pu(n, F) and ²³⁵U(n, F) reactions.

The occurrence of like-nucleon pair correlations in the ground state of spherical even–even nuclei is considered on the basis of the special Bogoliubov transformation. It is confirmed that, in closed-subshell nuclei, superconducting pair correlations occur at coupling constants G greater than a certain threshold value. Rough estimates of upper and lower bounds are obtained for the threshold value. It is shown that, in open-subshell nuclei, superconducting correlations exist at any positive G, and nucleon pairs are distributed over all subshells participating in the pairing interaction.

This work is devoted to the search for lambda hyperons and short-lived neutral kaons born in nuclear collisions in the Baryonic Matter at Nuclotron (BM@N) experiment, implemented at the Joint Institute for Nuclear Research (JINR, Dubna). To analyze the influence of different sources on the effectiveness of strange particle reconstruction algorithms, Monte Carlo simulations of the collision of a 3.9 AGeV Xe beam with a CsI target were used. After reconstruction of events and selection of candidate pairs, distributions of invariant masses were obtained and peaks corresponding to lambda hyperons and neutral kaons were identified. An analysis of the impact of each of the sources on the reduction of reconstruction efficiency was performed.

The current study aims to analyze the experimental data for deuterons elastically scattered by ^6,7Li, ⁹Be, and ¹¹B in the energy range from 8 to 50 MeV, applying semi-microscopic and microscopic methods (São Paulo potential (Optical Model) and coupled discretized continuum channels (CDCC)). The double-folding São Paulo Potential (SPP) was used as a real part of optical potential where the Woods–Saxon form was used as an imaginary part. The comparison between the optical model (OM) and the CDCC method is applied to the considered systems. The optical model parameters and the normalization factors have an influence on the fitting of the experimental data. The volume integral of the imaginary part of the optical potential was found to be slightly energy-dependent. Deuterons elastically scattered by light nuclei ^6,7Li, ⁹Be, and ¹¹B were well described using the CDCC method, where the breakup of the deuteron was included during the analysis. The break-up of the deuteron has a significant effect on the calculated reaction cross section σ_R of all the systems under consideration.

Photoionization (PI) of iron-group elements (Fe, Co, and Ni) is investigated in this article in the framework of the screening constant per unit nuclear charge (SCUNC) method. The resonance energies of several series of autoionizing Rydberg resonances identified in the PI spectra of these three transition elements are reported. The results of the SCUNC calculations in this study, which is considered to be the first theoretical study, are compared with the available experimental data and show minimal deviation of the theoretically calculated values from the experimental data. The correspondences obtained are very satisfactory, clarifying the uncertain resonance energies measured for certain series. This comparison reinforces confidence in the available experimental and theoretical data, as well as in the new data extrapolated in this study for astrophysical applications. The theoretical data for iron, cobalt and nickel presented in this work make a significant contribution to improving the fundamental atomic database of transition elements, providing valuable references for future calculations and potential astrophysical applications.

The MPD detector is one of two at NICA collider. The Master Scada software was suggested to be integrated with the MPD detector control system. The Time Projection Chamber is the main tracking detector of MPD experiment. The OPC UA server protocol and CAEN hardware form the foundation of the TPC LV and HV systems concept. The current status of the graphic user interface design for CAEN equipment, based on OPC UA, the Master SCADA for HV and LV is presented.