Physics of Atomic Nuclei最新文献

In this article we describe the (eta_{c}) production in proton–proton collisions at small values of the transverse momentum of the charmonium. Soft gluon resummation is used as a TMD factorization approach. At small transverse momenta, the color singlet contribution dominates, allowing us to use (eta_{c}) as a test of the resummation scheme for the noncollinear gluon PDF. The cross sections of (eta_{c}) production at (sqrt{s}=27) GeV, (115) GeV and (13) TeV are predicted.

The burgeoning interest in theoretical physics, particularly within the microscopic domain and in the context of many-body systems, necessitates the employment of the ({}^{4})He nucleus as an exemplar for the investigation of nuclear forces via an array of theoretical modelling methodologies. Rigorous importance of the study of alpha–nucleon system developed the curiosity among the physicists to deal with the problem by the formalism of two body scattering theory. The alpha–neutron system was analyzed using a modified Hylleraas potential as the nuclear interaction component, while the alpha–proton system incorporated an additional pure Coulomb potential to model the electromagnetic interaction. It is argued that the traditional phase function method (PFM) does not hold good for pure Coulomb and Coulomb-like interaction and needs modification. For brevity, it is conjectured here that local Coulomb-like potential is equally applicable for the traditional phase function method which will be examine through some model calculations. The scattering phase shifts for ({}^{2}S_{1/2}), ({}^{2}P_{1/2}), ({}^{2}P_{3/2}), ({}^{2}D_{3/2}) and ({}^{2}D_{5/2}) states of both the alpha–neutron and alpha–proton systems at a laboratory energy of 12.5 MeV were computed using the Phase Function Method. The calculated phase shifts were then compared to previously reported data, revealing a strong agreement that emphasizes the validity and effectiveness of the present methodological approach.

The study results of the (d+{}^{1}textrm{H}to p+p+n) reaction are presented. A kinematically complete experiment with using a deuteron beam energy of 15.3 MeV at the U-120 accelerator of the Skobeltsyn Institute of Nuclear Physics of the Lomonosov Moscow State University was carried out. A proton from the breakup of the singlet (pp) state and a secondary neutron were registered in coincidence. As a result of the study, the low-energy characteristics of (pp) interaction, namely, the energy value of the virtual singlet (pp) state and the corresponding value of the (pp) scattering length were determined.

The scintillation experiment of the TAIGA astrophysical complex comprises two systems: Tunka-Grande and Taiga-Muon. The main objective of these systems is to study the energy spectrum and mass composition of cosmic rays in the energy range of (10^{15}{-}10^{18}) eV, as well as to search for gamma radiation in the same energy range. An additional task of the experiments is to search for a signal from gamma quanta in the sub-PeV energy range in conjunction with wide angle Cherenkov detectors TAIGA-HiSCORE and Tunka-133. The report presents the objectives and status of the facility and a description of the design of scintillation counters and clusters. The results of the study of EAS with an unusual spatiotemporal structure are presented together with the results of a study of the joint operation of the Tunka-Grande and TAIGA-HiSCORE setups in order to search for sub-PeV gamma quanta. Estimates are made of the expected number of registered gamma quanta from the Crab Nebula.

Tile scintillators are the widely used technology in HEP experiments. The technology implies wavelength shifters (WLS) to collect light from a tile and guide it toward a photomultiplier and provides homogeneous readout from tiles with low dependence on tile shape and size. For this purpose, WLSs must provide appropriate light transportation along with good light trapping efficiency and time performance. Here we present results of comparative study of light collection and losses for two WLSs: Kurarai Y-11 and Saint Gobain BCF-92.

The neutrino evolution in realistic magnetic fields of astrophysical objects such as supernova bursts and neutron stars is studied. For the first time, we have derived an effective Hamiltonian for neutrinos propagating in nondipolar magnetic fields and obtained appropriate probabilities for neutrino oscillations.

An application of the SS-HORSE–NCSM approach with realistic nucleon–nucleon forces to the search of resonant states in three-nucleon system is discussed.

In 2022, a hybrid muon hodoscope with a sensitive area of (3times 3) m({}^{2}) for studying the internal structure of large-scale objects using the muonography method was created at MEPhI. The hodoscope’s detecting system has a hybrid structure. It consists of a scintillation strip detector and a drift tube detector and is designed to record tracks of charged particles. The muonography method is based on the use of cosmic ray muons as penetrating radiation for ‘‘translucence’’ (analogous to radiography) of large-scale objects. Experimental studies of the internal structure of the Kalinin NPP power unit using the muonography method were carried out in 2022–2023. The paper presents a brief description of the design of a hybrid muon hodoscope, as well as the results of an experiment on diagnostics of the power unit structure using this method, which was carried out during the scheduled power unit’s maintenance. The purpose of the experiment was to develop a method for real-time detection of changes in the structure of a reactor unit during its maintenance.

In the framework of the modified general relativity theory—the so called quartet-metric gravity/spontaneously broken relativity, objects to be called ‘‘dark holes’’ merging central black holes and peripheral scalar graviton dark haloes are considered. It is shown that the dark holes may naturally explain the effect of asymptotically flat rotation curves, attributed generally to the presence of some more conventional dark matter. Prospects of further modification of the discussed basic dark holes, to convert them to more realistic ones for application in astrophysics and cosmology, are outlined.

In this paper, in the framework of the random phase approximation, we investigate the properties of even–even nuclei in the vicinity of the remote doubly magic nucleus ({}^{78})Ni. The energies of the levels and probabilities of electromagnetic transitions in the considered nuclei are calculated. A comparison of the results with the currently available few experimental data is carried out.