Physics of Particles and Nuclei最新文献

The status of the study of (2403 pm 98) events of the ({{pi }^{ - }} + {text{Be}} to ;phi {{pi }^{0}}; + ;A{kern 1pt}^{*}) reaction collected in the exposition of a Be target of the VES setup to (2.5 times {{10}^{{11}}}) ({{pi }^{ - }}) mesons with a momentum of 29 GeV/c is presented. The (phi {{pi }^{0}}) production in the vector state predominantly associated with the (Delta (1232)) isobar in the process with (pi )-exchange dominance is observed. The (phi {{pi }^{0}}) mass spectrum has a complicated shape.

The paper presents in detail the methodology for simulation radiation conditions during operation of stations and channels for applied research SIMBO and ISCRA of the NICA complex of JINR. The Monte Carlo program FLUKA was used for simulation. The calculation results for the main operating modes of the stations are presented and discussed. The limiting intensities, at which the established zoning for the personnel is observed, are calculated. The obtained estimates show that the adopted design solutions ensure compliance with radiation safety standards during operation of stations with the limiting beam intensities determined as a result of simulation.

The magnetic measurement systems based on the wire’s techniques are universal and potential precision. Achieve to necessary measurement’s precision requires to calibration of the measurement equipment and a decreasing of systematic errors at the commissioning stage. This work describes an experience of based-on-wire magnetic measurement system commissioning for measure the magnets of the NICA accelerator complex at the Joint Institute for Nuclear Research (Dubna).

The problem of computing functional integrals in quantum mechanics models is considered. Functional integrals in models of the harmonic oscillator, double well potential, and Morse potential were computed using a neural network algorithm for normalizing flows. A comparison was made with results obtained from Monte Carlo simulation.

Using the Newman–Janis algorithm, rotating solutions were obtained for the Horndesky and bumblebee models. Mathematical modelling of black hole shadow profiles was conducted for the case of the two most probable configurations of Sgr A*. As a result, it is shown that the Horndesky model weakens the rotation effect (like gravity with nonlocal corrections), while the bumblebee model, in contrast, enhances it.

The main methods for measuring the cross sections in the VES experiment, which studies meson-nuclear interactions on a fixed target at a beam momentum of 29 GeV/c, are presented. A comparative analysis of different methods has been performed, their systematic errors have been estimated, and the verification of these methods based on the reactions with known cross sections is presented. Special attention is paid to the beam intensity-dependent effects in the measurements of cross sections.

This paper presents an overview of the latest results and research methodology of statistical combination of Higgs invisible searches at ATLAS Large Hadron Collider experiment using data collected in Run I ((sqrt s ) = 7 TeV, 8 TeV) and Run II ((sqrt s ) = 13 TeV). In this search, multiple production modes of the Standard Model Higgs boson were considered. Obtained upper limit on H → inv branching ratio of 0.107 (0.077) at the 95% confidence level is observed (expected). This result is the most strict up to date. Obtained values at the ATLAS experiment are compared with the results of direct-search experiments.

The scheme of a plasma neutron generator on a plasma target, theoretical and applied aspects of modeling the magnetohydrodynamic flow of controlled plasma, substantiation of the discretization of condensed plasma and ion fluxes based on the introduction of the concept of flow discreteness stemming from the development of methods and technology for creating and forming electronically controlled ion and plasma fluxes in magnetic fields by grouping fluxes in certain sequences are briefly considered. The operation of the developed installations is based on the physical principles of discrete compaction of plasma and ion flows by changing the control parameters of magneto-optical systems. Preliminary experiments have been carried out on a setup with a plasma electric generator for irradiating semiconductor heterostructures to create radiation-induced defects.

In addition to the proton–proton (pp) chain consisting only of isotopes of hydrogen and helium fusion of hydrogen into helium occurs in stars through the carbon-nitrogen-oxygen (CNO) cycle, in which the nuclear synthesis is catalyzed by C, N, and O nuclei. The CNO cycle produces only 1% of all solar energy and it is secondary for the Sun. However, for more massive and hot stars this cycle is dominant. In 2020–2023 the international Borexino collaboration presented results on first detection of neutrinos emitted in CNO cycle reactions on the Sun. The research also obtained results on measuring the beta spectrum of ²¹⁰Bi, knowing which is necessary to register the signal from CNO neutrinos.

Calibration experiments with artificial neutrino sources ⁵¹Cr and ³⁷Ar in the gallium solar neutrino experiments SAGE and GALLEX showed a neutrino capture rate significantly lower than expected. This result, known as the gallium anomaly, was later confirmed at a significance level of more than 4σ in the BEST experiment on the UNU GGNT with a ⁵¹Cr source. For a detailed study of the gallium anomaly, the BEST-2 experiment on a gallium target with an artificial source of ⁵⁸Co is proposed.