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Nuclear Theory·nucl-th

Tuesday·August 11, 2015

13 papers—6 primary·7 cross-listed

All13Primary6Cross-lists7
  1. 01

    Differential Hanbury-Brown-Twiss for an exact hydrodynamic model with rotation

    S. Velle🇳🇴 · L.P. Csernai🇳🇴

    We study an exact rotating and expanding solution of the fluid dynamical model of heavy ion reactions, that take into account the rate of slowing down of the rotation due to the longitudinal and transverse expansion of the system. The parameters of the model are set on the basis of realistic 3+1D fluid dynamical calculation at TeV energies, where the rotation is enhanced by the build up of the Kelvin Helmholtz Instability in the flow.

    nucl-thPRC(2015)·8 citations
  2. 02

    Global calculations on the microscopic energies and nuclear deformations: Isospin dependence of the spin-orbit coupling

    Zhe-Ying Wu · Chong Qi · Ramon Wyss · Hong-Liang Liu

    The microscopic energies and nuclear deformations of about 1850 even-even nuclei are calculated systematically within the macroscopic-microscopic framework using three Woods-Saxon parameterizations, with different isospin dependences, which were constructed mainly for nuclear spectroscopy calculations. Calculations are performed in the deformation space . Both the monopole and doubly stretched quadrupole interactions are considered for the pairing channel. The ground state deformations obtained by the three calculations are quite similar to each other. Large differences are seen mainly in neutron-rich nuclei and in superheavy nuclei. Systematic calculations on the shape-coexisting second minima are also presented. As for the microscopic energies of the ground states, the results are also very close to each other. Only in a few cases the difference is larger than 2 MeV. The total binding energy is estimated by adding the macroscopic energy provided by the usual liquid drop model with its parameters fitted through the least square root and minimax criteria. Calculations are also compared with the results of other macroscopic-microscopic mass models. All the three calculations give similar values for the deformations, microscopic energies and binding energies of most nuclei. One may expect to have a better understanding of the isospin dependence of the spin-orbital force with more data on proton- and neutron-rich nuclei.

    nucl-thPRC(2015)·33 citations
  3. 03

    Density dependence of the pairing interaction and pairing correlation in unstable nuclei

    S. A. Changizi · Chong Qi

    This work aims at a global assessment of the effect of the density dependence of the zero-range pairing interaction. Systematic Skyrme-Hartree-Fock-Bogoliubov calculations with the volume, surface and mixed pairing forces are carried out to study the pairing gaps in even-even nuclei over the whole nuclear chart. Calculations are also done in coordinate representation for unstable semi-magic even-even nuclei. The calculated pairing gaps are compared with empirical values from four different odd-even staggering formulae. Calculations with the three pairing interactions are comparable for most nuclei close to -stability line. However, the surface interaction calculations predict neutron pairing gaps in neutron-rich nuclei that are significantly stronger than those given by the mixed and volume pairing. On the other hand, calculations with volume and mixed pairing forces show noticeable reduction of neutron pairing gaps in nuclei far from the stability.

    nucl-thPRC(2015)·37 citations
  4. 04

    Empirical pairing gaps, shell effects, and di-neutron spatial correlation in neutron-rich nuclei

    S.A. Changizi · Chong Qi · R. Wyss

    The empirical pairing gaps derived from four different odd-even mass staggering formulas are compared. By performing single- shell and multi-shell seniority model calculations as well as by using the standard HFB approach with Skyrme force we show that the simplest three-point formula can provide a good measure of the neutron pairing gap in even- nuclei. It removes to a large extent the contribution from the nuclear mean field as well as contributions from shell structure details. It is also less contaminated by the Wigner effect for nuclei around . We also show that the strength of can serve as a good indication of the two-particle spatial correlation in the nucleus of concern and that the weakening of in some neutron-rich nuclei indicates that the di-neutron correlation itself is weak in these nuclei.

    nucl-thNPA(2015)·52 citations
  5. 05

    Partial restoration of isospin symmetry for neutrinoless double beta decay in the deformed nuclear system of Nd

    Dong-Liang Fang🇨🇳 · Amand Faessler🇩🇪 · Fedor Simkovic🇷🇺

    In this work, we calculate the matrix elements of -decay of Nd with the deformed pn-QRPA method. We adopted the approach introduced by Rodin, Faessler [Phys. Rev. C84, 014322 (2011)] and Simkovic {\it et. al.} [Phys. Rev. C87,045501(2013)] to restore the isospin symmetry by enforcing . We found that with this restoration, the Fermi matrix elements are reduced by about 30\% while the more important Gamow-Teller matrix elements remains the same. The results of an enlarged model space is also presented, which changes the matrix elements by less than 10\%.

    nucl-thPRC(2015)·35 citations
  6. 06

    Probing Pb+Pb collisions at GeV with spectators

    Vipul Bairathi🇮🇳 · Sandeep Chatterjee🇮🇳 · Md. Rihan Haque🇮🇳 · Bedangadas Mohanty🇮🇳

    There is event by event geometric as well as quantum fluctuations in the initial condition of heavy-ion collisions. The standard technique of analysing heavy-ion collisions in bins of centrality obtained from final state multiplicity averages out the various initial configurations and thus restricts the study to only a limited range of initial conditions. In this paper, we propose an additional binning in terms of total spectator neutrons in an event. This offers us a key control parameter to probe events with broader range of initial conditions providing us an opportunity to peep into events with rarer initial conditions which otherwise get masked when analysed by centrality binning alone. We find that the inclusion of spectator binning allows one to vary and independently. We observe that the standard scaling relation between and exhibited by centrality bins is broken by the spectator neutron bins. However, the acoustic scaling relation between and transverse system size holds for both centrality as well as spectator bins for central to mid-central collisions. The introduction of the spectator binning allows us to tune over a wide range viscosity driven effects for events with varying initial states but similar final state multiplicity.

    nucl-thhep-exhep-phnucl-exPLB(2016)·5 citations

Affiliations

first authorsco-authorsvia INSPIRE