Depth of the Maximum of Extensive Air Showers (EASes) and the Mean Mass Composition of Primary Cosmic Rays in the 1015^{15}–1018^{18} eV Range of Energies, According to Data from the TUNKA-133 and TAIGA-HiSCORE Arrays for Detecting EAS Cherenkov Light in the Tunkinsk Valley

A corrected energy dependence of the depth of the maximum in the wide range of energies 10$^{15}$ to 10$^{18}$ eV is obtained using data collected at the Tunka-133 facility over 7 years of operation (2009–2017) and the TAIGA-HiSCORE facility in the 2019–2020 season. At the highest energies, our results match those of the Pierre Auger observatory. The results are converted to parameter ❬ln A❭, which characterizes the mean EAS composition

Spin and orbital angular momentum separation: Theorem on decomposition

Recently, the problem of spin and orbital angular momentum (AM) separation has widely been discussed. Nowadays, all discussions about the possibility to separate the spin AM from the orbital AM in the gauge invariant manner are based on the ansatz that the gluon field can be presented in form of the decomposition where the physical gluon components are additive to the pure gauge gluon components, i.e. $A_\mu = A_\mu^{\text{phys}}+A_\mu^{\text{pure}}$. In the present paper, we show that in the non-Abelian gauge theory this gluon decomposition has a strong mathematical evidence in the frame of the contour gauge conception. In other words, we reformulate the gluon decomposition ansatz as a theorem on decomposition and, then, we use the contour gauge to prove this theorem. In the first time, we also demonstrate that the contour gauge possesses the special kind of residual gauge related to the boundary field configurations and expressed in terms of the pure gauge fields. As a result, the trivial boundary conditions lead to the inference that the decomposition includes the physical gluon configurations only provided the contour gauge condition

Study of Λ\Lambda Identification Method by the π−p→K0Λ\pi ^{ - }p \to K^{0}\Lambda Reaction for a Λp Scattering Experiment at J-PARC

The π− p → K0Λ reaction is an important elementary process to produce Λ from a proton target andis a key for a Λp scattering experiment where the momentum of Λ should be tagged from the missingmomentum of the (π−, K0) reaction. However, the (π−, K0) spectroscopy method has not been established yet due to the difficulty of the K0 detection. Therefore, we have proposed a new K0 detectionmethod where π+and π−from the K0 decay are measured by a forward magnetic spectrometer and adetector cluster surrounding the target, respectively. The feasibility of the K0 detection method wasconfirmed by analyzing the J-PARC E40 data taken with such a detector system. In the analysis, Λ’swere successfully identified in the missing mass spectrum of the π− p → K0X reaction

The use of Boosted Decision Trees for Energy Reconstruction in JUNO experiment

The Jiangmen Underground Neutrino Observatory (JUNO) is a neutrino experiment with a broad physical program. The main goals of JUNO are the determination of the neutrino mass ordering and high precision investigation of neutrino oscillation properties. The precise reconstruction of the event energy is crucial for the success of the experiment. JUNO is equiped with 17612 + 25600 PMT channels of two kind which provide both charge and hit time information. In this work we present a fast Boosted Decision Trees model using small set of aggregated features. The model predicts event energy deposition. We describe the motivation and the details of our feature engineering and feature selection procedures. We demonstrate that the proposed aggregated approach can achieve a reconstruction quality that is competitive with the quality of much more complex models like Convolution Neural Networks (ResNet, VGG and GNN)

Rate of decline of the production cross section of superheavy nuclei with ZZ=114–117 at high excitation energies

The production cross sections of superheavy nuclei with charge numbers 114–117 are predicted in the (5–9)n evaporation channels of the Ca48-induced complete fusion reactions for future experiments. The estimates of synthesis capabilities are based on a uniform and consistent set of input nuclear data provided by the multidimensional microscopic-macroscopic approach. The contributions of various factors to the final production cross section are discussed. As shown, the specific interplay between survival and fusion probabilities unexpectedly leads to a relatively slow decline of the total cross sections with increasing excitation energy. This effect is supported by a favorable arrangement of fission barriers protecting the compound nucleus against splitting concerning energetic thresholds for the emission of successive neutrons. In particular, the probabilities of the formation of superheavy nuclei in the 5n, 6n, and in some cases even 7n evaporation channels are still promising. This may offer a new opportunity for the future synthesis of unknown neutron-deficient superheavy isotopes

Complete set of bound negative-parity states in the neutron-rich 18N nucleus

High-resolution gamma-ray spectroscopy of 18N is performed with the Advanced GAmma Tracking Array AGATA, following deep-inelastic processes induced by an 18O beam on a 181Ta target. Six states are newly identified, which together with the three known excitations exhaust all negative-parity excited states expected in 18N below the neutron threshold. Spin and parities are proposed for all located states on the basis of decay branchings and comparison with large-scale shell-model calculations performed in the p-sd space, with the YSOX interaction. Of particular interest is the location of the 0^-_1 and 1^-_2 excitations, which provide strong constrains for cross-shell p-sd matrix elements based on realistic interactions, and help to simultaneously reproduce the ground and first-excited states in 16N and 18N, for the first time. Understanding the 18N structure may also have significant impact on neutron-capture cross-section calculations in r-process modeling including light neutron-rich nuclei

A Passive Shield for the RED-100 Neutrino Detector

A combined passive shield of the RED-100 two-phase emission neutrino detector has been developed and built for suppressing the background of external γ rays and neutrons. The shield is composed of a5-cm-thick copper layer (the inner layer is adjacent to the detector) and a water layer with a total thickness ofapproximately 70 cm (including the water inside the copper shield). The Monte Carlo simulation of theshielding efficiency has been performed. The obtained attenuation factor of the copper shield for the γ-raybackground has been experimentally verified in a laboratory test using a NaI(Tl) scintillator detector.The γ-ray background rejection factor of the full shield has also been calculated

Octupole correlations near 110^{110}Te

The lifetime of the 2+ and 9−, 11−, 13−, 15− states in the neutron-deficient Te110 was measured for the first time using the recoil distance Doppler shift technique. The reported value of the reduced transition probability B(E2;0g.s+→2+)=4.3(8)×103e2fm4 supports the systematic for even-mass Te isotopes and was interpreted in the framework of the large-scale shell model and cranked shell model calculations. The measured reduced transition probabilities in the negative-parity yrast band revealed the upward trend towards the high spins. The enhanced collectivity is discussed in terms of the tilted axis cranking approach and the symmetry configuration mixing method with the Gogny D1S interaction

The cross section of the process e+e−→ppˉe^+e^- \to p\bar{p} in the vicinity of charmonium ψ(3770)\psi(3770) including three-gluon and DD-meson loop contributions

The total cross section of the process $e^+e^- \to p\bar{p}$ is calculated within the energy range close to the mass of $\psi(3770)$ charmonium state. It was shown that the main contribution to this cross section comes from three gluon mechanism which is also responsible of the large phase with respect to the Born amplitude. This phase provides the characteristic dip behaviour of the cross section in contrast to the usual Breit-Wigner peak shape. OZI-allowed mechanism with D-mesons in the intermediate state was also estimated and gives relatively small contribution to the cross section and to the phase