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Nuclear Theory·nucl-th

Monday·March 11, 2019

10 papers—6 primary·4 cross-listed

All10Primary6Cross-lists4
  1. 07

    [Submitted on 7 Mar 2019] (cross-list from hep-ph)

    Exact solution for the non-equilibrium attractor in number-conserving relaxation time approximation

    Michael Strickland🇺🇸 · Ubaid Tantary🇺🇸

    We extend previous studies of the conformal 0+1d kinetic non-equilibrium attractor in relaxation time approximation by enforcing number conservation through the introduction of a dynamical fugacity (chemical potential). We derive two coupled integral equations for the effective temperature and fugacity which are then solved numerically to obtain the exact solution. The resulting solutions exhibit convergence to a unique non-equilibrium attractor when the scaled moments of the distribution function are plotted as a function of the rescaled time w = tau/tau_eq. This occurs even though the system is out of chemical equilibrium at late times. In addition, compared to the case where number conservation was not imposed, we find that the moments converge to their respective attractors more quickly, particularly for moments with m=0. Finally, we compare the resulting attractor moments with predictions from different hydrodynamic frameworks.

    Comments:
    19 pages, 5 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1903.03145 [pdf]
    JHEP(2019)·44 citations
  2. 08

    [Submitted on 8 Mar 2019] (cross-list from nucl-ex)

    2018 Update of the Discoveries of Nuclides

    Michael Thoennessen

    The 2018 update of the discovery of nuclide project is presented. 50 new nuclides were observed for the first time in 2018. A large number of isotopes is still only published in conference proceedings or internal reports.

    Comments:
    Accepted for publication in IJMPE
    Subjects:
    Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    1903.03224 [pdf]
    IJMPE(2019)·9 citations
  3. 09

    [Submitted on 8 Mar 2019] (cross-list from astro-ph.HE)

    The Equation of State and Cooling of Hyperonic Neutron Stars

    Laura Tolos · Mario Centelles · Angels Ramos · Rodrigo Negreiros · Veronica Dexheimer

    We present two recent parametrizations of the equation of state (FSU2R and FSU2H models) that reproduce the properties of nuclear matter and finite nuclei, fulfill constraints on high-density matter stemming from heavy-ion collisions, produce 2 neutron stars, and generate neutron star radii below 13 km. Making use of these equations of state, cooling simulations for isolated neutron stars are performed. We find that two of the models studied, FSU2R (with nucleons) and, in particular, FSU2H (with nucleons and hyperons), show very good agreement with cooling observations, even without including nucleon pairing. This indicates that cooling observations are compatible with an equation of state that produces a soft nuclear symmetry energy and, thus, generates small neutron star radii. Nevertheless, both schemes produce cold isolated neutron stars with masses above .

    Comments:
    6 pages, 4 figures, 1 table, invited parallel talk at Fifteenth Marcel Grossmann Meeting, University of Rome "La Sapienza" - Rome, July 1-7, 2018
    Subjects:
    High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
    arXiv:
    1903.03525 [pdf]
    2 citations
  4. 10

    [Submitted on 8 Mar 2019] (cross-list from hep-ph)

    Hard dilepton production from a weakly magnetized hot QCD medium

    Aritra Das🇮🇳 · Najmul Haque🇮🇳 · Munshi G. Mustafa🇮🇳 · Pradip K. Roy🇮🇳

    We have computed the hard dilepton production rate from a weakly magnetized deconfined QCD medium within one-loop photon self-energy by considering one hard and one thermomagnetic resummed quark propagator in the loop. In the presence of the magnetic field, the resummed propagator leads to four quasiparticle modes. The production of hard dileptons consists of rates when all four quasiquarks originating from the poles of the propagator individually annihilate with a hard quark coming from a bare propagator in the loop. Besides these, there are also contributions from a mixture of pole and Landau cut part. In weak field approximation, the magnetic field appears as a perturbative correction to the thermal contribution. Since the calculation is very involved, for a first effort as well as for simplicity, we obtained the rate up to first order in the magnetic field, i.e., , which causes a marginal improvement over that in the absence of magnetic field.

    Comments:
    21 pages, 7 figures, published version
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1903.03528 [pdf]
    PRD(2019)·24 citations

Affiliations

first authorsco-authorsvia INSPIRE