Physics of Atomic Nuclei最新文献

The energies and electrical properties of the octupole states of the ({}^{238})U nucleus are studied within the framework of a phenomenological model considering the Coriolis mixing of rotational bands. Mixing of the low-lying negative parity bands is considered. The energies, the structures of states of rotational bands with (K^{{pi}}=0^{-}), (1^{-}), (2^{-}), (3^{-}), and the reduced probabilities of E1 transitions are calculated. Theoretical energy values and (E)1 transitions’ probabilities are compared with the experimental data. Good agreement between experimental data and theoretical results is obtained.

In November 2020, the IceCube Neutrino Observatory registered a neutrino event with an energy of 150 TeV directed at the Cygnus Cocoon gamma-ray source. In the Carpet-2 experiment, as part of the Baksan Neutrino Observatory (BNO), a sharp increase in the flow of events with an energy above 300 TeV was recorded from the same direction within the angular accuracy of the events. This flux is 4 orders of magnitude higher than the expected intensity of gamma quanta of this energy region according to data in the region of less than 100 TeV. It was expected that such a powerful flare could be registered by the TAIGA-HiSCORE installation of the TAIGA astrophysical complex. We analyzed the events of the EAS recorded by the installation of TAIGA-HiSCORE for 18 h in October–November 2020 from the Cygnus Cocoon source. This article provides the upper limit of the expected excess flow.

The existence of dibaryons, the systems with baryon number two, is one of the central questions in modern nuclear physics. It is closely connected with the problem of phase transitions in nuclear matter, various manifestations of which are being searched for in the experiments with colliding heavy nuclei. Since the theory of these processes is very difficult, the interpretation of such data usually contains large uncertainties. At the same time there is a possibility of understanding some features of these processes in the collision of the lightest nuclei–deuterons. Exploring such an opportunity at the future NICA SPD is the focus of this paper. It is shown that while using Kinematical fit technique at the simulation of the process (d+drightarrow d+X) below meson production threshold, the accuracy of the estimation of the (X) mass is on the level 2–3 MeV/(c) when the deuteron moment of the NICA Collider is equal to 2.6 GeV/c (below (MX) is used as a mass of (X), i.e. (MX=M_{d}+E_{textrm{exc}}), where (M_{d}), (E_{textrm{exc}}) are deuteron mass and excitation energy). The system (X) is called sometimes as dibaryons below.

A detailed analytic calculation of one-loop electromagnetic radiative corrections in Møller scattering beyond the ultrarelativistic approximation is presented, all masses being completely taken into account. The infrared divergence is removed by means of the covariant approach proposed by Bardin and Shumeiko. A successful numerical comparison of the radiative effects in question with the results obtained earlier in which the infrared divergence was removed by alternative methods was performed over a broad kinematical range. A kinematical region where the use of the ultrarelativistic approximation should be avoided in order obtain a precision estimate of radiative effects is determined.

Measurement of electroweak production of single heavy vector bosons in (pp)-collisions at the LHC is an important test for new physics. The most interesting case is the so-called vector boson fusion process which involves trilinear gauge coupling constant. This paper summarizes experimental results on electroweak production cross sections of events with leptonic decays of (W)- and (Z)-bosons plus two hadron jets. They are based on datasets accumulated by the ATLAS and CMS detectors at (sqrt{s}=7), (8) and (13) TeV during Run1 and Run2 of the LHC.

The recent results on charmonium production at BESIII are reviewed, including the observation of charmonium-like states in the processes of electron–positron annihilation into (D^{*0}D^{*-}pi^{+}), (omega X(3872)), (K^{0}_{s}K^{0}_{s}J/psi), and (pi^{+}pi^{-}psi_{2}(3823)) final states, as well as the study of the prompt inclusive production of the (J/psi) and (psi(3686)) mesons.

At an experiment on acceleration of a polarized proton beam up to an energy at (13text{ GeV}), the possibility of crossing the transition energy at (5.7text{ GeV}) by a jump is considered. The scheme of crossing by a rapid change of transition energy, assumes the longitudinal movement in Barrier Bucket RF near the zero value of the slip-factor. The jump itself is carried out in the absence of an RF field. The paper presents the influence of the above features on the dynamics of a polarized beam.

First results on (A)-dependence measurements in inclusive (K_{S}^{0}) meson production in (pi^{-}A) interactions ((A=textrm{C}), Al, Cu, Sn, and W) are presented at ({approx}26.5) GeV/c. The ratios of the differential cross sections of four of these nuclei to the differential cross section on aluminum were measured and the dependence of these cross sections on the atomic of the nucleus was studied. The measurements were carried out in the kinematic region of the Feynman variable (0.2<x_{textrm{F}}<0.8) and transverse momentum (p_{T}<1.2) GeV/c. (K_{S}^{0}) mesons were detected in the decay mode (K_{S}^{0}topi^{+}pi^{-}) at the SPASCHARM experimental setup using negative charged beams at beamline 14 of the U-70 accelerator complex.

The production of (Z) bosons in proton–proton collisions and the LHC energies is studied. The production cross sections for (Z) bosons and their transverse-momentum spectra are calculated along with the lepton angular coefficients as functions of the (Z)-boson transverse momentum. The calculations are performed within the parton Reggeization approach in the leading-order approximation in the strong coupling constant ((Qbar{Q}to Z)) and with allowance for the next-to-leading-order correction associated with Reggeized-quark scattering on a Reggeized gluon ((RQto Zq)). A numerical simulation is performed by means of the KaTie Monte Carlo generator. The results of the calculations are compared with experimental data of the ATLAS Collaboration.