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Nuclear Theory·nucl-th

Thursday·April 27, 2017

9 papers—6 primary·3 cross-listed

All9Primary6Cross-lists3
  1. 01

    Probing the spacetime evolution of heavy ion collisions with photons and dileptons

    Jean-François Paquet🇺🇸

    Photons and dileptons are emitted throughout the evolution of the deconfined nuclear medium produced in heavy ion collisions. As such they can provide valuable information about the different phases of the medium, and complement hadronic measurements and other observables. In this work, recent developments related to electromagnetic emissions at early time, in the cross-over region, and at late times are reviewed. The spacetime description of the nuclear medium from a hydrodynamic model of heavy ion collisions is used to provide context and guide the discussion.

    nucl-thhep-phNPA(2017)·23 citations
  2. 02

    Equation of state of a quark-meson mixture in the improved-PNJL model at finite chemical potential

    Juan M. Torres-Rincon🇩🇪 · Joerg Aichelin🇫🇷

    We study the equation of state of QCD using an improved version of the three-flavor Polyakov-Nambu-Jona-Lasinio model beyond the mean-field approximation. It incorporates the effects of unquenched quarks into the Polyakov-loop effective potential, as well as mesonic contributions to the grand-canonical potential. We study in full detail the calculation of the thermodynamical potential in this approach and compare the resulting pressure and entropy density with the most-recent lattice-QCD calculations at zero baryochemical potential. Finally, we present some exploratory results at finite chemical potential which include the phase diagram of the model, the quark and meson masses, and finally, the thermodynamical pressure.

    nucl-thhep-phPRC(2017)·35 citations
  3. 03

    Reduced transition probabilities for the gamma decay of the 7.8 eV isomer in Th

    Nikolay Minkov · Adriana Pálffy

    The reduced magnetic dipole and electric quadrupole transition probabilities for the radiative decay of the Th 7.8 eV isomer to the ground state are predicted within a detailed nuclear-structure model approach. We show that the presence and decay of this isomer can only be accounted for by the Coriolis mixing emerging from a remarkably fine interplay between the coherent quadrupole-octupole motion of the nuclear core and the single-nucleon motion within a reflection-asymmetric deformed potential. We find that the magnetic dipole transition probability which determines the radiative lifetime of the isomer is considerably smaller than presently estimated. The so-far disregarded electric quadrupole component may have non-negligible contributions to the internal conversion channel. These findings support new directions in the experimental search of the Th transition frequency for the development of a future nuclear frequency standard.

    nucl-thnucl-exPRL(2017)·78 citations
  4. 04

    Isovector properties of the nuclear energy density functional from the quark-meson coupling model

    E. McRae🇦🇺 · C. Simenel🇦🇺 · E. C. Simpson🇦🇺 · A. W. Thomas🇦🇺

    Background: The Skyrme energy density functional is widely used in mean-field calculations of nuclear structure and dynamics. However, its reliance on phenomenology may compromise its isovector properties and its performance for exotic nuclear systems. Purpose: This work investigates the possibility of removing some phenomenology from the density functional by drawing on the high-energy degrees-of-freedom of the quark-meson coupling (QMC) model. The QMC model has microscopically derived isovector properties and far fewer adjustable parameters. Method: The parameters of the Skyrme interaction are fixed using the energy density functional of the QMC model, to give the Skyrme-QMC (SQMC) parameterisation. Results: Hartree-Fock-Bogoliubov calculations of the Sn, Pb and chains are reported, in which SQMC performs with an accuracy comparable to modern phenomenological functionals. Conclusions: The isovector terms of the energy density functional are significant for the binding energies of neutron-rich nuclei. The isovector dependence of the nuclear spin-orbit interaction must be taken into account for calculations of r-process nucleosynthesis abundances.

    nucl-thPoS(2017)·2 citations
  5. 05

    Bose-Einstein condensation and liquid-gas phase transition in alpha-matter

    L. M. Satarov🇩🇪 · M. I. Gorenstein🇩🇪 · A. Motornenko🇩🇪 · V. Vovchenko🇩🇪 · I. N. Mishustin🇩🇪 · H. Stoecker🇩🇪

    Systems of Bose particles with both repulsive and attractive interactions are studied using the Skyrme-like mean-field model. The phase diagram of such systems exhibits two special lines in the chemical potential-temperature plane: one line which represents the first-order liquid-gas phase transition with the critical end point, and another line which represents the onset of Bose-Einstein condensation. The calculations are made for strongly-interacting matter composed of alpha particles. The phase diagram of this matter is qualitatively similar to that observed for the atomic He4 liquid. The sensitivity of the results to the model parameters is studied. For weak interaction coupling the critical point is located at the Bose-condensation line.

    nucl-thJ.Phys.G(2017)·21 citations
  6. 06

    Relative mass distributions of neutron-rich thermally fissile nuclei within statistical model

    Bharat Kumar · M.T. Senthil kannan · M. Balasubramaniam · B. K. Agrawal · S. K. Patra

    We study the fission yield of recently predicted thermally fissile neutron-rich uranium and thorium nuclei using statistical model. The level density parameters needed for the study are evaluated from the excitation energies of temperature dependent relativistic mean field formalism. The excitation energy and the level density parameter for a given temperature are employed in the convolution integral method to obtain the probability of the particular fragmentation. As representative case, we present the results for the binary fission yield of 250 U and 254 Th. The relative yields are presented for three different temperatures T = 1, 2 and 3 MeV.

    nucl-thPRC(2017)·7 citations

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first authorsco-authorsvia INSPIRE