查看更多>>摘要：Statistical properties of nuclear energy levels and nuclear transitions have long been juxtaposed to the limit of random matrix theory. A novel practical measure of chaos onset, the ratio of consecutive energy spacings, that does not require the unfolding of energy levels, was previously introduced for all three canonical random matrix ensembles, along with the expressions for the regular and chaotic limits. In this study, an expression for this ratio interpolating between the regular and chaotic limits is introduced and applied to the energy levels calculated in the realistic nuclear shell model and in the interacting boson model. The results are consistent with those extracted from the traditional statistics of nearest-neighbor spacings with unfolding; we find the relation between the ways of convergence to the chaotic limit. (c) 2022 Elsevier B.V. All rights reserved.
Dahiwale, S. S.Suryanarayana, S., VBhoraskar, V. N.Dhole, S. D....
20页
查看更多>>摘要：The cross sections of the 88Sr(n,2n)87Srm, 88Sr(n,p)88Rb, 88Sr(n,alpha)85Kr, 86Sr(n,2n)85Srm, 86Sr(n,2n)85Srg and 84Sr(n,2n)83Sr nuclear reactions at 14.77 +/- 0.17 MeV neutron energy and the average cross sections of the 88Sr(gamma ,n)87Srm and 86Sr(gamma ,n)85Srm nuclear reactions at bremsstrahlung of 15 MeV endpoint energy were measured with the activation method and offline gamma-ray spectroscopy. The measured cross sections were reported with a detailed covariance analysis for uncertainty and correlation coefficients. The experimental results were compared with the previously reported experimental data from the EXFOR database and the evaluated data from the TENDL-2019 library. Statistical model calculations were performed with the latest TALYS-1.95 code with optimised input parameters to better reproduce reported experimental data. The measured cross sections were found to be in good agreement with the literature and theoretical calculations. These results highlight the alternate production routes for the medical radioisotopes of 87Srm and 85Srg. (c) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：We present improved estimates of the couplings, masses and mass ratios of the Z(Q), X-Q and T-QQ (q) over bar(q) over bar' states (Q = c, b; q, q' = u, d, s) using (inverse) QCD Laplace sum rules (LSR), their ratios Rand double ratios DRSR within stability criteria, where the NLO factorized PT QCD corrections are included which is important for giving a meaning on the running (MS) over bar heavy quark mass used in the analysis. We show that combined Rand DRSR can provide more precise results. In the 1st part of the paper, we conclude that the observed X-c(3872) and Z(c)(3900) are tetramolesstates (superposition of quasi-degenerated molecule and a tetraquark states having (almost) the same coupling to the currents) with the predicted masses: M-TXc = 3876(44) MeVand M-TZc = 3900(42) MeV. In the 2nd part, we focus on the analysis of the four-quark nature of different T-QQ (q) over bar(q) over bar' 1(+) and 0(+) states within the (3) over bar (c)3(c) interpolating currents. The final results from Rand R-circle plus DRSR are summarized in Table7. Combined Rand DRSR calibrated to the observed X-c(3872) lead to a precise prediction of e.g. MTcc1+ = 3886(6) MeV. In a similar way, the DRSR for the MTcc0+/MTcc1+ calibrated to MTcc1+ gives MTcc0+ = 3883(3) MeV. The SU3 breaking ratios MTcc (s) over bar(s) over bar0+/MTcc0+ cclead to the improved mass predictions: MTcc (s) over bar(s) over bar0+ = 3988(12) MeV. In the 3rd part, the analysis is extended to the beauty mesons, where we find the tetramole masses: M-TZb = 10579(99) MeVand M-Xb = 10545(131) MeV. We also observe that the T-bb (q) over bar(q) over bar'(1+,0+) (q, q' = u, d, s) states are (almost) stable (within the errors) against strong interactions. In the 4th part, we (critically) review and correct some recent LSR estimates of the T-QQ (q) over bar(q) over bar'(1+,0+) masses. Our combined LSR circle plus DRSR results are confronted with the ones from some other approaches (lattices and quark models) in Fig. 26. (C) 2022 Elsevier B.V. All rights reserved.
Nassurlla, MaulenBurtebayev, N.Sakuta, S. B.Karakozov, B. K....
14页
查看更多>>摘要：At an energy of 14.5 MeV, the elastic and inelastic scattering of deuterons and the (d, t) reaction on 11B nuclei were studied. Experimental angular distributions with transitions to the states of the 11B nucleus (ground state (3/2(-)), 4.445 (5/2(-)) MeV, 6.743 (7/2(-)) MeV) and to the states of the 10B nucleus (ground state (3+), 0.718 MeV (1+), 1.74 MeV (0+, T = 1), 2.15 MeV (1+)) were analyzed by the coupled channel method. The value of the quadrupole deformation parameter beta(2)= 0.80 +/- 0.2 was extracted. The assumption of a direct mechanism for picking up a neutron in the reaction (d, t) made it possible to describe rather well the measured angular distributions for the states of the 10B nucleus. The values of the spectroscopic amplitudes for the transitions to these states have been extracted. It is shown that the mechanism of 8Be transfer both in the form of a whole cluster and in the sequential transfer of two alpha-particles does not play a significant role. It was found that the deformation of the 10B and 11B nuclei noticeably affects the calculated cross sections for the (d, t) reaction. (C) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：In the present work, we have studied the structural properties, alpha and clusters (Be-8, C-12, O-16, Ne-20, and Mg-24) decay half-lives for the Th, U, and Pu isotopes using the well-known Relativistic Mean-Field (RMF) theory with NL3* parameter set. We calculate the binding energy per nucleon, root-mean-square (rms) radii, two-neutron separation energies (S-2n), and other observables. The results are in good agreement with the finite-range droplet model (FRDM) and experimental data. Using the calculated mass defect results from these calculations, the Effective liquid drop model (ELDM) has been used to determine alpha and cluster decay half-lives. The half-lives calculations are also carried out by using the latest empirical relations, namely Universal Decay Law (UDL), TM, VS, and the Scaling Law was given by Horoi et al., and their comparisons with ELDM results are found to be in good agreement. In the plots for log10T1/2 versus the neutron number of the daughter nucleus N-d in the corresponding decay, the half-life is found to have a minimum for the decay leading to nearly doubly magic or doubly magic daughter 208Pb nucleus (N-d = 126). The Geiger-Nuttal plots for different clusters from various cluster radioactive (CR) emitters have been studied and they clearly show a linear behavior. (C) 2022 Elsevier B.V. All rights reserved
查看更多>>摘要：We investigate the effect of repulsive interaction between hadrons on the specific heat (CV ), isothermal compressibility (kappa(T)) and the speed of sound (C-s(2)) of hot and dense hadronic matter. The repulsive inter-actions are included through a mean-field approach where the single particle energy picks correction term due to mean field interactions between hadrons. This correction term is proportional to the number density of hadrons. We assume different mean-field interactions for mesons and baryons. We also confront CV and C-s(2) with existing lattice QCD simulation results. We find that the repulsive interactions have very strong effect on CV and C-s(2) while its effect on kappa(T) is very mild. We finally discuss the implications of our results in the context of heavy-ion collision experiments. (C) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：The neutron-capture and Maxwellian-averaged cross sections of Ta-181(n, gamma) reaction have been com-puted making use of the TALYS code. Two main inputs of the TALYS calculation, nuclear level density (NLD) and radiative strength function (RSF), are calculated within a recent microscopic model that takes into account the exact thermal pairing plus independent-particle model and collective excitations within the phonon-damping model. A good agreement between the calculated and experimental NLD and RSF data of Ta-182 was found, confirming the goodness of the microscopic nuclear model used. As the result, the deduced neutron-capture and Maxwellian-averaged cross sections of Ta-181(n, gamma) reaction also agree rea-sonably well with the experimental and recommended data across the measured energy range. The impact of the predicted cross sections on the tantalum production in the slow neutron-capture process (s-process) is then studied by employing a recent version of FRUITY stellar evolutionary models in which the effect of magnetic fields is newly implemented. By calculating the isotopic composition ratios within the FUNS code, we obtain a slight depletion of tantalum as compared to the recommended data. The variation between the calculated and reference tungsten isotopic ratios in presolar stardust silicon carbide (SiC) grains is found to be negligible, as expected. However, the capability of our theoretical model to reproduce experimental nuclear data will allow us to investigate in detail the s-process branching points at W-181 and W-185, for which experimental data from direct measurements are still unavailable. (C)& nbsp;2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：We study the near-threshold J/psi meson production on protons and nuclei by considering incoherent direct non-resonant K(-)p ->& nbsp;J/psi boolean AND and two-step resonant K(-)p ->& nbsp;P-cs(4459)(0)& nbsp;->& nbsp;J/psi boolean AND & nbsp;charmonium production processes. We calculate the absolute excitation functions, energy and momentum distributions for the non-resonant, resonant and for the combined (non-resonant plus resonant) production of J/psi mesons off protons as well as off carbon and tungsten target nuclei at near-threshold incident antikaon energies by considering these elementary production channels as well as by assuming the spin-parity assignment of the hidden-charm resonance P-cs(4459)(0) with strangeness as JP = (3/2)(-) within six different scenarios for the branching ratio Br[P-cs(4459)(0)& nbsp;->& nbsp;J/psi boolean AND] of the decay P-cs(4459)(0) ->& nbsp;J/psi boolean AND. We show that the combined observables considered reveal definite sensitivity to these scenarios, which means that they may be an important tool to provide further evidence for the existence of the pentaquark P-cs(4459)(0) resonance and to get valuable information on its decay rate to the J/psi boolean AND final state. Their measurements could be performed in the future at the J-PARC Hadron Experimental Facility. (C)& nbsp;2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：Motivated to explore the dynamical mechanism of multi-fragmentation phase transition and expand our knowledge on the deterministic chaos in nonlinear dynamic process, we study systematically the nonlinear dynamical behaviors of heavy ion collisions at intermediate energy. In order to highlight the general characteristics of the collision dynamics, in the present paper, we simulate a simple collision system, Ca + Ca, and obverse the performances of the typical nonlinear characteristic quantities such as the production of generalized entropy and the fractal structure of the semiclassical phase space during the reaction process. The multifragmentation entropy, information dimension and the dynamical fluctuations of fragment mass distribution in the final state of the reaction are also evaluated. Our results about the intermediate processes and the final products of the reaction are verified mutually so that confirm strongly the existence of nonlinear chaos in the heavy ion collisions at intermediate energy. Meanwhile, we find that the typical characteristics of the critical phase transition obtained in the analysis of the final production of the reaction are relatively more clear in the vicinity of the incident energies E = 100 MeV. (c) 2022 Elsevier B.V. All rights reserved.
查看更多>>摘要：A systematic investigation of the structural evolution of the even-even isotones of 40 < Z < 50 nuclei in 50 < N < 60 range of neutron numbers has been done from the calculations of total Routhian surfaces (TRS) in the macroscopic-microscopic formalism. The calculations predict that the nuclei with N = 56 are transitional ones with an onset of deformation at N >= 56. It has been found that the shape of the midshell Ru (Z = 44) isotopes is mostly gamma-soft near the ground state. The TRS calculations at higher rotational frequencies ((h) over line)omega) for Ru-100,Ru-102 show a shape evolution in these nuclei from a prolate-like gamma-soft to a stable triaxial shape. Such stable triaxial shapes in the even-even cores are important to explain the observed chiral bands in the odd-odd Rh nuclei. A common general feature that has been found for the heavier nuclei from this work is the shape invariance of the nuclei with same numbers of total (proton + neutron) valence particles away from N, Z = 50. (C)& nbsp;2022 Elsevier B.V. All rights reserved.
NSTL
Elsevier