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Nuclear Theory·nucl-th

Friday·February 9, 2018

6 papers—4 primary·2 cross-listed

All6Primary4Cross-lists2
  1. 01

    Deuteron: analytical forms of wave function and density distribution

    V.I. Zhaba

    The deuteron wave function can be presented as the table through the respective massifs of numerically values of radial wave functions. In calculations such arrays of numbers in the texts of programs to operate quite difficult. Therefore a used simpler analytical forms is expedient. In the received analytical forms of deuteron wave function in coordinate representation it is necessary to calculate density distribution in the deuteron and transition density and compare them among themselves. On the received coefficients of the four analytical forms for deuteron wave function for the nucleon-nucleon potential Reid93 are calculated density distribution and transition density. For comparison, similar results are given for Moscow potential. Such calculations help to evaluate the correctness of the choice of the analytical form for approximation of the wave function, and also to obtain information about such characteristics of the deuteron as charge form factor, tensor polarization and momentum distribution.

    nucl-thAPS Physics(2017)·1 citation
  2. 02

    Analytical forms of the wave function and the asymmetry for polarization characteristics of the deuteron

    V.I. Zhaba

    The basic analytical forms of the deuteron wave function (DWF) in a coordinate representation have been reviewed. The asymptotic behaviour of DWF near the origin of coordinates has been analyzed. New analytical forms of DWF as a product of the exponential function r^n and the sum of the exponential terms Ai*exp(-ai*r3) are applied for the calculation of the polarization characteristics of the deuteron. Numerical calculations have been done for realistic phenomenological potential of Nijmegen groups, Reid93. In the paper, the results of the angular asymmetry for deuteron vector t10, t11 and tensor t20, t21, t22 polarizations are described. Along with the angular asymmetry, the momentum asymmetry for deuteron vector t1i polarizations is described too. The influence of DWF approximation in a coordinate representation on the subsequent results of the calculations of the tensor polarization t20 is investigated. A comparison of values t20 is made at 70 degree if to apply four different DWF approximations to the same NN-potential Reid93. When the received theoretical values t20 are compared with the experimental data of world collaborations and reviews, a good coordination for the area of values momentum p=1-4fm-1 is observed. Using the method of invariant amplitude, spin observables in backward elastic dp-scattering-tensor analyzing power T20 and polarization transfer K0 have been calculated. The values of K0 and correlation K0-T20 are compared with experimental data. In a wide range of momentums p and scattering angles, the asymmetry for the tensor analyzing power T20 and T22 has been presented, which characterizes the photoproduction of negative pi- meson from deuteron in reaction g(d, pi-)pp. A symmetry of values T20 and T22 concerning a 90 angle is observed. The ratio R for the vector Px and tensor Pxz polarizations is characterized by angular asymmetry....

    nucl-thJ.Phys.Stud.(2017)·5 citations
  3. 03

    Quadrupole and octupole collectivity and cluster structures in neon isotopes

    P. Marević🇫🇷 · J.-P. Ebran🇫🇷 · E. Khan🇫🇷 · T. Nikšić🇭🇷 · D. Vretenar🇭🇷

    The lowest positive- and negative-parity bands of Ne and neutron-rich even-even Ne isotopes are investigated using a theoretical framework based on energy density functionals. Starting from a self-consistent relativistic Hartree-Bogoliubov calculation of axially-symmetric and reflection-asymmetric deformation energy surfaces, the collective symmetry-conserving states are built using projection techniques and the generator coordinate method. Overall a good agreement with the experimental excitation energies and transition rates is obtained. In particular, the model provides an accurate description of the excitation spectra and transition probabilities in Ne. The contribution of cluster configurations to the low-energy states is discussed, as well as the transitional character of the ground state. The analysis is extended to Ne and the shape-coexisting isotope Ne, and to the drip-line nuclei Ne and Ne. The role of valence neutrons in the formation of molecular-type bonds between clusters is discussed.

    nucl-thPRC(2018)·53 citations
  4. 04

    Spectroscopic Criteria for Identification of Nuclear Tetrahedral and Octahedral Symmetries: Illustration on a Rare Earth Nucleus

    J. Dudek🇫🇷 · D. Curien🇫🇷 · I. Dedes🇵🇱 · K. Mazurek🇵🇱 · S. Tagami🇯🇵 · Y. R. Shimizu🇯🇵 · T. Bhattacharjee🇮🇳

    We formulate criteria for identification of the nuclear tetrahedral and octahedral symmetries and illustrate for the first time their possible realization in a Rare Earth nucleus 152Sm. We use realistic nuclear mean-field theory calculations with the phenomenological macroscopic-microscopic method, the Gogny-Hartree-Fock-Bogoliubov approach and the general point-group theory considerations to guide the experimental identification method as illustrated on published experimental data. Following group-theory the examined symmetries imply the existence of exotic rotational bands on whose properties the spectroscopic identification criteria are based. These bands may contain simultaneously states of even and odd spins, of both parities and parity doublets at well defined spins. In the exact-symmetry limit those bands involve no E2-transitions. We show that coexistence of tetrahedral and octahedral deformations is essential when calculating the corresponding energy minima and surrounding barriers and that it has a characteristic impact on the rotational bands. The symmetries in question imply the existence of long-lived shape-isomers and, possibly, new waiting point nuclei -- impacting the nucleosynthesis processes in astrophysics -- and an existence of 16-fold degenerate particle-hole excitations. Specifically designed experiments which aim at strengthening the identification arguments are briefly discussed.

    nucl-thnucl-exPRC(2018)·33 citations
  5. 05

    Nuclear physics uncertainties of the astrophysical gamma-process studied through the 64Zn(p,alpha)61Cu and 64Zn(p,gamma)65Ga reactions

    Gy. Gyürky · Zs. Fülöp · Z. Halász · G. G. Kiss · T. Szücs

    In a recent work, the cross section measurement of the 64Zn(p,alpha)61Cu reaction was used to prove that the standard alpha-nucleus optical potentials used in astrophysical network calculation fail to reproduce the experimental data at energies relevant for heavy element nucleosynthesis. In the present paper the analysis of the obtained experimental data is continued by comparing the results with the predictions using different parameters. It is shown that the recently suggested modification of the standard optical potential leads to a better description of the data.

    ↳ nucl-exnucl-thJ.Phys.Conf.Ser.(2018)·2 citations
  6. 06

    Event-by-Event Efficiency Fluctuations and Efficiency Correction for Cumulants of Superposed Multiplicity Distributions in Relativistic Heavy-ion Collision Experiments

    Shu He🇨🇳 · Xiaofeng Luo🇨🇳

    We performed systematic studies on the effects of event-by-event efficiency fluctuations on efficiency correction for cumulant analysis in relativistic heavy-ion collision experiments. Experimentally, particle efficiencies of events measured under different experimental conditions should be different. For fluctuation measurements, the final event-by-event multiplicity distributions should be the superposed distributions of various type of events measured under different conditions. We demonstrate efficiency fluctuation effects using numerical simulation, in which we construct an event ensemble consisting of events with two different efficiencies. By using the mean particle efficiencies, we find that the efficiency corrected cumulants show large deviations from the original inputs when the discrepancy between the two efficiencies is large. We further studied the effects of efficiency fluctuations for the cumulants of net-proton distributions by implementing the UrQMD events of Au+Au collisions at GeV in a realistic STAR detector acceptance. We consider the unequal efficiency in two sides of the Time Projection Chamber (TPC), multiplicity dependent efficiency, and the event-by-event variations of the collision vertex position along the longitudinal direction (). When the efficiencies fluctuate dramatically within the studied event sample, the effects of efficiency fluctuations have significant impacts on the efficiency corrections of cumulants with the mean efficiency. We find that this effect can be effectively suppressed by binning the entire event ensemble into various sub-event samples, in which the efficiency variations are relatively small. The final efficiency corrected cumulants can be calculated from the weighted average of the corrected factorial moments of the sub-event samples with the mean efficiency.

    ↳ physics.data-anhep-exhep-lathep-ph+2CPC(2018)·12 citations

Affiliations

first authorsco-authorsvia INSPIRE