Physics of Atomic Nuclei最新文献

Recent experimental results on searches for non-resonant Higgs boson pair production at the LHC are summarized and expected sensitivity to this process at the high-luminosity LHC is discussed. These results are based on analyzes of complete datasets accumulated by the ATLAS and CMS detectors in proton–proton collisions at (sqrt{s}=13) TeV which correspond to about 140 fb({}^{-1}) integrated luminosity, and on their projections to data equivalent to 3000 fb({}^{-1}) at (sqrt{s}=14) TeV expected at the HL-LHC.

Search and study of exotic hadrons—tetraquarks and pentaquarks—is one of topical problems in modern high energy physics. To determine spin–parity of these states, test theoretical predictions of their spectra and reveal the internal structure—high-precision measurements of their parameters are required. Amplitude analysis is a recognized tool for solving this problem. In this paper, the details of amplitude analysis approaches together with practical examples of their application are presented.

The main goal of the GERDA experiment was to search for the neutrinoless double-beta decay of ({}^{76})Ge. Beside this, many other GERDA results of searching for various processes beyond the Standard Model were obtained. Among them, a possible manifestation of the inclusive, mode independent decays of a single neutron and proton and some specific modes of tri-nucleon decays in ({}^{76})Ge were investigated, as well as a possible decay of an electron via channel (e^{-}tonu_{e}gamma). A search for full energy depositions from bosonic keV-scale dark matter candidates has been performed too.

The paper presents the results of an algorithm based on the study of characteristics of ion tracks in optically transparent solid-state detectors (meteoritic olivine, glasses, synthetic and natural micas) for determining the ion charge and energy. The resistance of tracks detected in the tested materials to high temperatures is under study. The tested materials are promising, in particular, for recording fragments of spontaneous fission of superheavy nuclei synthesized at accelerators.

In this letter it has been demonstrated that there exist so-called weak dualities of QCD phase diagram that exhibit themselves only in the case when only one phenomenon is important in the phase structure and others can be neglected. Despite their limitations weak dualities can provide us with a lot of information about phase structure and shows various symmetries of phase diagram. It deserves to be stressed that there are weak dualities that incorporate baryon chemical potential that is particularly intriguing.

Formation of intermediate mass and light nuclei in the excited and rapidly expanding nuclear matter is investigated. We demonstrate that this phenomenon can be explained within the statistical approach by applying the concept of local equilibrium. We subdivide the expanding nuclear system into several parts (primary clustering), consisting of nucleons, close in phase space. Inside these primary clusters the process of nucleation takes place, which can be described as the statistical decay of such clusters in the coexistence region of nuclear liquid-gas phase transition. Within this approach one can explain simultaneously both yield and kinetic (flow) energy of the produced nuclei, that wasn’t possible when considering global chemical equilibrium in the whole nuclear system. We believe that our approach can be a generalization of the freeze-out volume concept, developed for multifragmentation reactions at high energy. The influence of isospin on the process is investigated. The mechanism of such a production of nuclei, including exotic nuclear species, can be realized in central collisions of heavy ions at intermediate energies.

DANSS is a one cubic meter highly segmented solid scintillator detector. DANSS is placed on a lifting platform under a 3.1 GW({}_{textrm{th}}) power reactor of the Kalinin Nuclear Power Plant. The distance from the reactor core center to the detector is varied from 10.9 to 12.9 m. The inverse beta decay (IBD) reaction is used for antineutrinos detection. DANSS sees about 5000 IBD events per day with a few percent of cosmic muons background. In this paper the result of the reactor power reconstruction for nearly 8 years based on the IBD rates with 1(%) accuracy is presented. Also the fission fractions of ({}^{235})U and ({}^{239})Pu are calculated with 2.4(%) accuracy for 10-day time periods using the IBD spectra with excluded bump region. More than that, a new method is proposed to calculate the IBD yield ratio (dfrac{sigma_{5}}{sigma_{9}}) with an error significantly smaller than in previous experimental works. Besides several methods of the remote observation of the amount of ({}^{239})Pu that produced by a reactor were tested.

The Baryonic Matter at Nuclotron (BM@N) experiment is designed to investigate the properties of matter under extreme conditions of high baryon density. In early 2023, BM@N conducted its first physics run, collecting hundreds of millions of collisions between xenon and cesium iodide ions at a beam energy of 3.8 GeV per nucleon ((sqrt{s_{NN}}=) 3.26 GeV). We present preliminary results for the directed flow ((v_{1})) of protons relative to the spectator symmetry plane. We discuss the potential impact of non-flow correlations on the final results and estimate the associated systematic uncertainty.

Motivated by the rapid development of heavy-flavor experiments, we study the two-body hadronic (bar{B}_{d,s}^{*}to D_{d,s}^{*}P) decays within the framework of QCD factorization. Here the pseudoscalar (P) represents pion and kaon mesons. We present the branching fractions and polarization fractions for (bar{B}_{d,s}^{*}to D_{d,s}^{*}pi) decay. Compared to (bar{B}_{d,s}^{*}to D_{d,s}^{*}K) decays, the (bar{B}_{d,s}^{*}to D_{d,s}^{*}pi) decays exhibit relatively larger branching fractions in numerically, on the order ({gtrsim}{O}(10^{-8})). We evaluate the QCD correction to the longitudinal and transverse amplitudes at next-to-leading order, finding that the transverse amplitudes dominate with a branching ratio of approximately 50(%).

The paper examines the application of various methods for calculating azimuthal flows in Monte Carlo generator HYDJET++—the reaction plane method and the two-particle cumulant method. A comparison of the data obtained in the generator with the CMS experiment is given.