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Nuclear Theory·nucl-th

Wednesday·March 1, 2017

5 papers—2 primary·3 cross-listed

All5Primary2Cross-lists3
  1. 01

    [Submitted on 27 Feb 2017]

    Induced fission of 240Pu

    A. Bulgac · S. Jin · P. Magierski · K.J.Roche · I. Stetcu

    We study the fission dynamics of 240Pu within an implementation of the Density Functional Theory (DFT) extended to superfluid systems and real-time dynamics. We demonstrate the critical role played by the pairing correlations. The evolution is found to be much slower than previously expected in this fully non-adiabatic treatment of nuclear dynamics, where there are no symmetry restrictions and all collective degrees of freedom (CDOF) are allowed to participate in the dynamics.

    Comments:
    8 pages, 4 figures, talk given at The 6th International Conference on Fission and Properties of Neutron-Rich Nuclei, Sanibel Island, Florida, November 6-2 (2016)
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1702.08490 [pdf]
    pages 564-572, in Fission and Properties …·0 citations
  2. 02

    [Submitted on 28 Feb 2017]

    Effective field theory description of halo nuclei

    H.-W. Hammer · C. Ji · D. R. Phillips

    Nuclear halos emerge as new degrees of freedom near the neutron and proton driplines. They consist of a core and one or a few nucleons which spend most of their time in the classically-forbidden region outside the range of the interaction. Individual nucleons inside the core are thus unresolved in the halo configuration, and the low-energy effective interactions are short-range forces between the core and the valence nucleons. Similar phenomena occur in clusters of He atoms, cold atomic gases near a Feshbach resonance, and some exotic hadrons. In these weakly-bound quantum systems universal scaling laws for s-wave binding emerge that are independent of the details of the interaction. Effective field theory (EFT) exposes these correlations and permits the calculation of non-universal corrections to them due to short-distance effects, as well as the extension of these ideas to systems involving the Coulomb interaction and/or binding in higher angular-momentum channels. Halo nuclei exhibit all these features. Halo EFT, the EFT for halo nuclei, has been used to compute the properties of single-neutron, two-neutron, and single-proton halos of s-wave and p-wave type. This review summarizes these results for halo binding energies, radii, Coulomb dissociation, and radiative capture, as well as the connection of these properties to scattering parameters, thereby elucidating the universal correlations between all these observables. We also discuss how Halo EFT's encoding of the long-distance physics of halo nuclei can be used to check and extend ab initio calculations that include detailed modeling of their short-distance dynamics.

    Comments:
    104 pages, 31 figures. Topical Review for Journal of Physics G. v2 incorporates several modifications, particularly to the Introduction, in response to referee reports. It also corrects multiple typos in the original submission. It corresponds to the published version
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    1702.08605 [pdf]
    J.Phys.G(2017)·204 citations
  3. 03

    [Submitted on 24 Feb 2017] (cross-list from hep-th)

    Second-order dissipative hydrodynamics for plasma with chiral asymmetry and vorticity

    E. V. Gorbar🇺🇦 · D. O. Rybalka🇺🇸 · I. A. Shovkovy🇺🇸

    By making use of the chiral kinetic theory in the relaxation-time approximation, we derive an Israel-Stewart type formulation of the hydrodynamic equations for a chiral relativistic plasma made of neutral particles (e.g., neutrinos). The effects of chiral asymmetry are captured by including an additional continuity equation for the axial charge, as well as the leading-order quantum corrections due to the spin of particles. In a formulation of the chiral kinetic theory used, we introduce a symmetric form of the energy-momentum tensor that is suitable for the description of a weakly nonuniform chiral plasma. By construction, the energy and momentum are conserved to the same leading order in the Planck constant as the kinetic equation itself. By making use of such a chiral kinetic theory and the Chapman-Enskog approach, we obtain a set of second-order dissipative hydrodynamic equations. The effects of the fluid vorticity and velocity fluctuations on the dispersion relations of chiral vortical waves are analyzed.

    Comments:
    15 pages, published version
    Subjects:
    High Energy Physics — Theory (hep-th); Mesoscale and Nanoscale Physics (cond-mat.mes-hall); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1702.07791 [pdf]
    PRD(2017)·31 citations
  4. 04

    [Submitted on 28 Feb 2017] (cross-list from astro-ph.HE)

    Neutrino Emission from Supernovae

    H.-Th. Janka (MPI Astrophysics, Garching)🇩🇪

    Supernovae are the most powerful cosmic sources of MeV neutrinos. These elementary particles play a crucial role when the evolution of a massive star is terminated by the collapse of its core to a neutron star or a black hole and the star explodes as supernova. The release of electron neutrinos, which are abundantly produced by electron captures, accelerates the catastrophic infall and causes a gradual neutronization of the stellar plasma by converting protons to neutrons as dominant constituents of neutron star matter. The emission of neutrinos and antineutrinos of all flavors carries away the gravitational binding energy of the compact remnant and drives its evolution from the hot initial to the cold final state. The absorption of electron neutrinos and antineutrinos in the surroundings of the newly formed neutron star can power the supernova explosion and determines the conditions in the innermost supernova ejecta, making them an interesting site for the nucleosynthesis of iron-group elements and trans-iron nuclei. In this Chapter the basic neutrino physics in supernova cores and nascent neutron stars will be discussed. This includes the most relevant neutrino production, absorption, and scattering processes, elementary aspects of neutrino transport in dense environments, the characteristic neutrino emission phases with their typical signal features, and the perspectives connected to a measurement of the neutrino signal from a future galactic supernova.

    Comments:
    Author version of chapter for 'Handbook of Supernovae,' edited by A. Alsabti and P. Murdin, Springer. 30 pages, 9 figures
    Subjects:
    High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1702.08713 [pdf]
    134 citations
  5. 05

    [Submitted on 28 Feb 2017] (cross-list from astro-ph.HE)

    Constructing a neutron star in G2-QCD

    Ouraman Hajizadeh🇦🇹 · Axel Maas🇦🇹

    The inner structure of neutron stars is still an open question. To make progress and understand the qualitative impact of gauge interactions on the neutron star structure we study neutron stars in a modified version of QCD. In this modification the gauge group of QCD is replaced by the exceptional Lie group G, which has neutrons and is accessible at finite density in lattice calculations. Using an equation of state constructed from lattice calculations we determine the mass-radius-relation for a neutron star in this theory using the Tolman-Oppenheimer-Volkoff equation. The results exhibit an influence of the non-trivial interactions on the mass-radius relation. However, the masses of the quarks are found to have little influence. We also give density profiles and the phase structure inside the neutron star. If the results carry over to full QCD, much of the internal structure of neutron stars could already be inferred from a precise measurement of the mass-radius relation.

    Comments:
    (23 pages, 32 figures), Improved presentation, version to appear in European Physical Journal A
    Subjects:
    High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
    arXiv:
    1702.08724 [pdf]
    EPJA(2017)·10 citations

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first authorsco-authorsvia INSPIRE