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Nuclear Theory·nucl-th

Thursday·March 17, 2022

8 papers—6 primary·2 cross-listed

All8Primary6Cross-lists2
  1. 01

    [Submitted on 15 Mar 2022]

    Cold Quark-Gluon Plasma EOS Applied to a Magnetically Deformed Quark Star with an Anomalous Magnetic Moment

    Keith Andrew🇺🇸 · Eric Steinfelds🇺🇸 · Kristopher Andrew🇺🇸

    We consider a QCD cold plasma motivated Equation of State (EOS) to examine the impact of an Anomalous Magnetic Moment (AMM) coupling and small shape deformations for static oblate and prolate core shapes of quark stars. Using the Fogaça QCD motivated EOS which shifts from the high temperature low chemical potential quark gluon plasma environment to the low temperature high chemical potential quark stellar core environment we consider the impact of an AMM coupling with a metric induced shape deformation parameter in the TOV equations. The EOS is developed using a hard gluon and soft gluon decomposition of the gluon field tensor using a mean field effective mass for the gluons. The AMM is considered using the Dirac spin tensor coupled to the EM field tensor with quark flavor based magnetic moments. The shape parameter is introduced in a metric ansatz that represents oblate and prolate static stellar cores for modified TOV equations. These equations are numerically solved for the final mass and radius states representing the core collapse of a massive star with a phase transition leading to an unbound quark-gluon plasma. We find that the combined shape parameter and AMM effects can alter the coupled EOS-TOV equations resulting in an increase in the final mass and a decrease in the final equatorial radius without collapsing the core into a black hole and without violating causality constraints, we find maximum mass values in the range: 2.3 Solar Masses < M < 2.7 Solar Masses. These states are consistent with some astrophysical high mass magnetar/pulsar and gravity wave systems which may provide evidence for a core that has undergone a quark-gluon phase transition such as PSR 0943+10 and the secondary from the GW 190814 event.

    Comments:
    12 pages, 6 figures
    Subjects:
    Nuclear Theory (nucl-th); Solar and Stellar Astrophysics (astro-ph.SR); General Relativity and Quantum Cosmology (gr-qc)
    arXiv:
    2203.08241 [pdf]
    Universe(2022)·2 citations
  2. 02

    [Submitted on 16 Mar 2022]

    Manifestation of deformation and nonlocality in and cluster decay

    D. F. Rojas-Gamboa · J. E. Perez Velasquez · N. G. Kelkar · N. J. Upadhyay

    It is common to study the strong decay of a heavy nucleus as a tunneling phenomenon where the (He) or a light nuclear cluster tunnels through the Coulomb barrier formed by its interaction with the heavier daughter nucleus. The position and width of the Coulomb barrier are determined by the total interaction potential between the two daughter nuclei. We examine the effects of including nonlocality and deformation in the interaction potential by calculating the half-lives, , and thereby phenomenological preformation factors of several nuclei which have the possibility of decaying by emitting either an or a light nuclear cluster. The effect of deformation manifests itself by a decrease in for all the decays studied. The effect of nonlocality is studied within two different models of the nuclear potential: the energy-independent but angular momentum () dependent Mumbai (M) potential and the energy-dependent Perey-Buck (PB) potential. The nonlocal nuclear interaction leads to a decrease in all half-lives studied. Though the decrease is larger due to the Perey-Buck potential, half-lives evaluated using the Mumbai potential show a strong sensitivity to the value in the decay. This feature of the and cluster decay half-lives can provide a complementary tool in addition to scattering data which are more commonly used to fix the parameters of a nonlocal potential in literature.

    Comments:
    19 pages, 5 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2203.08363 [pdf]
    PRC(2022)·11 citations
  3. 03

    [Submitted on 16 Mar 2022]

    Significance of chiral three-nucleon force contact terms for understanding of elastic nucleon-deuteron scattering

    H. Witała · J. Golak · R. Skibiński

    We investigate the importance of the three-nucleon (3N) force contact terms in elastic nucleon-deuteron (Nd) scattering by applying the NLO chiral semi-local momentum space (SMS) regularized nucleon-nucleon (NN) chiral potential supplemented by NLO and all subleading NLO three-nucleon force (3NF) contact terms. Strength parameters of the contact terms were obtained by least squares fitting of theoretical predictions to cross section and analyzing powers data at three energies of the impinging nucleon. Although the NLO contributions to the 3N force were completely neglected, the results calculated with the contact terms multiplied by the fitted strength parameters yield an improved description of the elastic Nd scattering observables in a wide range of incoming nucleon energies below the pion production threshold.

    Comments:
    43 pages, 13 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2203.08499 [pdf]
    PRC(2022)·26 citations
  4. 04

    [Submitted on 16 Mar 2022]

    Nearly model-independent constraints on dense matter equation of state in a Bayesian approach

    N. K. Patra · Sk Md Adil Imam · B. K. Agrawal · Arunava Mukherjee · Tuhin Malik

    We apply Bayesian approach to construct a large number of minimally constrained equations of state (EOSs) and study their correlations with a few selected properties of a neutron star (NS). Our set of minimal constraints includes a few basic properties of saturated nuclear matter and low-density pure neutron matter EOS which is obtained from a precise next-to-next-to-next-to-leading-order (NLO) calculation in chiral effective field theory. The tidal deformability and radius of NS with mass are found to be strongly correlated with the pressure of -equilibrated matter at densities higher than the saturation density ( fm) in a nearly model-independent manner. These correlations are employed to parametrize the pressure for -equilibrated matter, around 2, as a function of neutron star mass and the corresponding tidal deformability. The maximum mass of neutron star is also found to be strongly correlated with the pressure of -equilibrated matter at densities .

    Comments:
    19 pages, 7 figures, Accepted in Physical Review D. arXiv admin note: text overlap with arXiv:2110.15776
    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc)
    arXiv:
    2203.08521 [pdf]
    PRD(2022)·36 citations
  5. 05

    [Submitted on 16 Mar 2022]

    Correlation between nuclear temperatures and symmetry energy in sub-saturation

    Fan Zhang · Kai-Lei Wang · Li-Ding Jin · Hui-Xiao Duan · Cheng Li

    A study of the correlation between nuclear temperatures and symmetry energy is presented for heavy-ion collisions at intermediate energies via the isospin-dependent quantum molecular-dynamics model. It is found that different symmetry energy parameters will change the density and kinetic energy distribution of the hot nuclei. More importantly, nuclear temperatures that are based on kinetic energy properties can be used to study symmetry energy information.

    Comments:
    5 pages,5 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2203.08562 [pdf]
    PRC(2022)·1 citation
  6. 06

    [Submitted on 16 Mar 2022]

    S pairing gaps, chemical potential and entrainment matrix in superfluid neutron-star cores for the Brussels-Montreal functionals

    Valentin Allard · Nicolas Chamel

    Temperature and velocity-dependent S pairing gaps, chemical potentials and entrainment matrix in dense homogeneous neutron-proton superfluid mixtures constituting the outer core of neutron stars, are determined fully self-consistently by solving numerically the time-dependent Hartree-Fock-Bogoliubov equations over the whole range of temperatures and flow velocities for which superfluidity can exist. Calculations have been made for in beta-equilibrium using the Brussels-Montreal functional BSk24. The accuracy of various approximations is assessed and the physical meaning of the different velocities and momentum densities appearing in the theory is clarified. Together with the unified equation of state published earlier, the present results provide consistent microscopic inputs for modeling superfluid neutron-star cores.

    Comments:
    36 pages, 19 figures. Numerical results for pairing gaps are available on the CompOSE database, see https://compose.obspm.fr/
    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
    arXiv:
    2203.08778 [pdf]
    Universe(2021)·19 citations

Affiliations

first authorsco-authorsvia INSPIRE