PaperPanorama
FAQ

Nuclear Theory·nucl-th

Wednesday·September 16, 2020

7 papers—4 primary·3 cross-listed

All7Primary4Cross-lists3
  1. 05

    [Submitted on 15 Sept 2020] (cross-list from hep-ph)

    Diquark Induced Short-Range Nucleon-Nucleon Correlations \& the EMC Effect

    Jennifer Rittenhouse West🇺🇸

    Diquark formation across a short-range nucleon-nucleon pair is proposed as the underlying QCD physics of short-range correlations (SRC) in nuclei. SRC pairs have been proposed as the cause of distorted quark behavior in nuclei; experimentally observed quark momentum distribution distortions termed the EMC effect. The strong spatial overlap of SRC pairs brings nucleon constituents within range of inter-nucleon QCD potentials and any bonds formed - such as the diquark bond - affects their distributions. In this SRC model, diquarks form in the channel of acting on valence quarks from highly overlapping nucleon wavefunctions. The most energetically favorable diquark is a valence quark from one nucleon with a valence quark from the other in a spin-0 state bound together via continual single gluon exchange and an attractive quantum chromodynamics short-range potential. Formation of a new scalar isospin-singlet diquark across a NN pair is proposed as the primary QCD-level theoretical foundation for SRC models of distorted structure functions in nuclei. Contributions from the higher mass spin-1 isospin triplet states , and are possible, with the spin-1 diquark proposed as a higher mass but viable structure function distortion mechanism for the spin-1 ground state deuteron. Predictions are made for lepton scattering experiments on and nuclear targets, with implications for the coefficients of the 3-valence quark Fock states in the nucleon wavefunction.

    Comments:
    Version accepted for publication in Nuc.Phys.A
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
    arXiv:
    2009.06968 [pdf]
    NPA(2023)·19 citations
  2. 06

    [Submitted on 15 Sept 2020] (cross-list from cond-mat.str-el)

    Proton fraction in neutron star matter: Dynamical mean-field approach

    Maxim Velikanov · Alexey N. Rubtsov · Boris Krippa

    Dynamical mean field theory (DMFT) is used to study neutron matter, both with and without admixture of the proton fraction. The system is approximated by the lattice Habbard model. The corresponding equation of state as a function of temperature/density/asymmetry is investigated. The results are compared with the standard mean field (MF) approach where the effect of local correlations is neglected. Whereas the influence of the correlations on the properties of a pure neutron matter is found to be moderate, it becomes strong when the proton admixture is taken into account. In particular, we calculate the proton fraction, energy density and pressure in outer core of neutron stars, taking into account the beta equilibrium condition. The DMFT predicts that the proton fraction is several times the MF based calculations, whereas the DMFT results for energy density and pressure are 30-40\% lower then the corresponding MF estimates. Physical implications of our findings for a neutron star dynamics are discussed.

    Subjects:
    Strongly Correlated Electrons (cond-mat.str-el); Nuclear Theory (nucl-th)
    arXiv:
    2009.07127 [pdf]
    New J.Phys.(2021)·1 citation
  3. 07

    [Submitted on 15 Sept 2020] (cross-list from astro-ph.HE)

    Unified Interacting Quark Matter and its Astrophysical Implications

    Chen Zhang🇨🇦 · Robert B. Mann🇨🇦

    We investigate interacting quark matter (IQM), including the perturbative QCD correction and color superconductivity, for both up-down quark matter (QM) and strange quark matter (SQM). We first derive an equation of state (EOS) unifying all cases by a simple reparametrization and rescaling, through which we manage to maximally reduce the number of degrees of freedom. We find, in contrast to the conventional EOS for non-interacting quark matter, that taking the extreme strongly interacting limit on the unified IQM EOS gives , where is the effective bag constant. We employ the unified EOS to explore the properties of pure interacting quark stars (IQSs) composed of IQM. We describe how recent astrophysical observations, such as the pulsar-mass measurements, the NICER analysis, and the binary merger gravitational-wave events GW170817, GW190425, and GW190814, further constrain the parameter space. An upper bound for the maximum allowed mass of IQSs is found to be . Our analysis indicates a new possibility that the currently observed compact stars, including the recently reported GW190814's secondary component (), can be quark stars composed of interacting quark matter.

    Comments:
    Final published version. 6 pages, 3 figures
    Subjects:
    High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2009.07182 [pdf]
    PRD(2021)·101 citations

Affiliations

first authorsco-authorsvia INSPIRE