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Nuclear Theory·nucl-th

Tuesday·January 28, 2020

11 papers—7 primary·4 cross-listed

All11Primary7Cross-lists4
  1. 08

    Evolution of Octupole Deformation in Radium Nuclei from Coulomb Excitation of Radioactive Ra and Ra Beams

    P.A. Butler🇬🇧 · L.P. Gaffney🇬🇧 · P. Spagnoletti🇬🇧 · K. Abrahams🇿🇦 · M. Bowry🇬🇧 · J. Cederkäll🇸🇪 · G. De Angelis🇮🇹 · H. De Witte🇧🇪 · P.E. Garrett🇨🇦 · A. Goldkuhle🇩🇪 · C. Henrich🇩🇪 · A. Illana🇮🇹 and 31 other authors

    There is sparse direct experimental evidence that atomic nuclei can exhibit stable pear shapes arising from strong octupole correlations. In order to investigate the nature of octupole collectivity in radium isotopes, electric octupole () matrix elements have been determined for transitions in Ra nuclei using the method of sub-barrier, multi-step Coulomb excitation. Beams of the radioactive radium isotopes were provided by the HIE-ISOLDE facility at CERN. The observed pattern of 3 matrix elements for different nuclear transitions is explained by describing Ra as pear-shaped with stable octupole deformation, while Ra behaves like an octupole vibrator.

    ↳ nucl-exhep-phnucl-thphysics.atom-phPRL(2020)·92 citations
  2. 09

    Equation of state and composition of the inner crust of an accreting neutron star: multicomponent model

    Nikolay N. Shchechilin · Andrey I. Chugunov

    Correct interpretation of X-ray observations of transiently accreting neutron stars requires modeling of nuclear-physical processes in these objects. We consider a chain of nuclear reactions that drives the crust composition in an accreting neutron star and heats up the star. We constructed multicomponent approach with the kinetics of nuclear reactions described in simplified stepwise manner. The redistribution of nucleons between nuclei by emission and capture of neutrons is shown to significantly affect the nuclear reaction chains and the composition of the inner crust. In particular, even if the outer crust has one-component composition, the appearance of free neutrons in the inner crust leads to branching of reaction chains and formation of the multicomponent composition. We apply the compressible liquid drop nuclear model, which includes effects of free neutrons on nuclear energies. It allows us to calculate the composition, the heating profile and the equation of state of matter up to densities \rho ~ 2 \times 10^{13} g cm^{-3}.

    ↳ astro-ph.SRastro-ph.HEnucl-thJ.Phys.Conf.Ser.(2019)·3 citations
  3. 10

    Superfluidity in Disordered Neutron Stars Crusts

    J. A. Sauls🇺🇸 · N. Chamel🇧🇪 · M. A. Alpar🇹🇷

    Nonequilibrium conditions imposed by neutrino cooling through the liquid-solid transition lead to disorder in the solid crust of neutron stars. Disorder reduces the superfluid fraction, , at densities above that of neutron drip, . For an amorphous solid crust the suppression of is small, except in the highest density regions of the crust. In contrast to the strong reduction in neutron conduction predicted for coherent Bragg scattering in a crystalline crust, the disordered solid crust supports sufficient neutron superfluid density to account for pulsar glitches.

    ↳ astro-ph.HEcond-mat.supr-connucl-th30 citations

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