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Nuclear Theory·nucl-th

Thursday·September 24, 2015

6 papers—3 primary·3 cross-listed

All6Primary3Cross-lists3
  1. 01

    [Submitted on 22 Sept 2015]

    Application of supersymmetric quantum mechanics to study bound state properties of exotic hypernuclei

    Md. Abdul Khan🇮🇳

    Bound state properties of few single and double- hypernuclei is critically examined in the framework of core- and core+ few-body model applying hyperspherical harmonics expansion method (HHEM). The potential is chosen phenomenologically while the core- potential is obtained by folding a phenomenological interaction into the density distribution of the core. The depth of the effective potential is adjusted to reproduce the experimental data for the core- subsystem. The three-body Schrödinger equation is solved by hyperspherical adiabatic approximation (HAA) to get the ground state energy and wave function. The ground state wavefunction is used to construct the supersymmetric partner potential following prescription of supersymmetric quantum mechanics (SSQM) algebra. The newly constructed supersymmetric partner potential is used to solve the three-body Schrödinger equation to get the energy and wavefunction for the first excited state of the original potential. The method is repeated to predict energy and wavefunction of the next higher excited states. The possible number of bound states is found to increase with the increase in mass of the core of the hypernuclei. The Root Mean Squared (RMS) matter radius and some other relevant geometrical observables are also predicted.

    Comments:
    20 Pages 10 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1509.06793 [pdf]
    0 citations
  2. 02

    [Submitted on 23 Sept 2015]

    Baryon stopping signal for mixed phase formation in HIC

    Yu. B. Ivanov🇷🇺

    It is argued that an irregularity in the baryon stopping is a natural consequence of onset of deconfinement occurring in the compression stage of a nuclear collision. It is an effect of the softest point inherent in an equation of state (EoS) with a deconfinement transition. In order to illustrate this effect, calculations within the three-fluid model were performed with three different EoS's: a purely hadronic EoS, an EoS with a first-order phase transition and that with a smooth crossover transition.

    Comments:
    4 pages, 2 figures, to be published in the Proceedings of the 15th International Conference on Strangeness in Quark Matter (SQM2015), 6-11 July 2015, JINR, Dubna, Russia
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    1509.06944 [pdf]
    J.Phys.Conf.Ser.(2016)·5 citations
  3. 03

    [Submitted on 23 Sept 2015]

    Nuclear Axial Currents in Chiral Effective Field Theory

    A. Baroni🇺🇸 · L. Girlanda🇮🇹 · S. Pastore🇺🇸 · R. Schiavilla🇺🇸 · M. Viviani🇮🇹

    Two-nucleon axial charge and current operators are derived in chiral effective field theory up to one loop. The derivation is based on time-ordered perturbation theory, and accounts for cancellations between the contributions of irreducible diagrams and the contributions due to non-static corrections from energy denominators of reducible diagrams. Ultraviolet divergencies associated with the loop corrections are isolated in dimensional regularization. The resulting axial current is finite and conserved in the chiral limit, while the axial charge requires renormalization. A complete set of contact terms for the axial charge up to the relevant order in the power counting is constructed.

    Comments:
    53 pages, 14 figures an error relative to the d_i has been corrected and references added. 1 page erratum, corrections on Eqs(7.2), (D4), (D10), (D11), and (D12)
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1509.07039 [pdf]
    PRC(2016)·95 citations
  4. 04

    [Submitted on 23 Sept 2015] (cross-list from hep-th)

    Glueball-baryon interactions in holographic QCD

    Si-wen Li🇨🇳

    Studying the Witten-Sakai-Sugimoto model with type IIA string theory, we find the glueball-baryon interaction is predicted in this model. The glueball is identified as the 11D gravitational waves or graviton described by the M5-brane supergravity solution. Employing the relation of M-theory and type IIA string theory, glueball is also 10D gravitational perturbations which are the excited modes by close strings in the bulk of this model. On the other hand, baryon is identified as a D4-brane wrapped on which is named as baryon vertex, so the glueball-baryon interaction is nothing but the close string/baryon vertex interaction in this model. Since the baryon vertex could be equivalently treated as the instanton configurations on the flavor brane, we identify the glueball-baryon interaction as "graviton-instanton" interaction in order to describe it quantitatively by the quantum mechanical system for the collective modes of baryons. So the effective Hamiltonian can be obtained by considering the gravitational perturbations in the flavor brane action. With this Hamiltonian, the amplitudes and the selection rules of the glueball-baryon interaction can be analytically calculated in the strong coupling limit. We show our calculations explicitly in two characteristic situations which are "scalar and tensor glueball interacting with baryons". Although there is a long way to go, our work provides a holographic way to understand the interactions of baryons in hadronic physics and nuclear physics by the underlying string theory.

    Comments:
    16 pages, adding the Appendix C and transition amplitude in this version
    Subjects:
    High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
    arXiv:
    1509.06914 [pdf]
    PLB(2017)·12 citations
  5. 05

    [Submitted on 23 Sept 2015] (cross-list from hep-ph)

    Magnetically induced QCD Kondo effect

    Sho Ozaki🇯🇵 · Kazunori Itakura🇯🇵 · Yoshio Kuramoto🇯🇵

    The "QCD Kondo effect" stems from the color exchange interaction in QCD with non-Abelian property, and can be realized in a high-density quark matter containing heavy-quark impurities. We propose a novel type of the QCD Kondo effect induced by a strong magnetic field. In addition to the fact that the magnetic field does not affect the color degrees of freedom, two properties caused by the Landau quantization in a strong magnetic field are essential for the "magnetically induced QCD Kondo effect"; (1) dimensional reduction to 1+1-dimensions, and (2) finiteness of the density of states for lowest energy quarks. We demonstrate that, in a strong magnetic field , the scattering amplitude of a massless quark off a heavy quark impurity indeed shows a characteristic behavior of the Kondo effect. The resulting Kondo scale is estimated as where and are the fine structure constant of strong interaction and the number of colors in QCD, and is the electric charge of light quarks.

    Comments:
    34 pages, 6 figures, version published in PRD
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Strongly Correlated Electrons (cond-mat.str-el); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
    arXiv:
    1509.06966 [pdf]
    PRD(2016)·39 citations
  6. 06

    [Submitted on 19 Sept 2015] (cross-list from astro-ph.HE)

    Cooling compact stars and phase transitions in dense QCD

    Armen Sedrakian

    We report new simulations of cooling of compact stars containing quark cores and updated fits to the Cas A fast cooling data. Our model is built on the assumption that the transient behaviour of the star in Cas A is due to a phase transition within the dense QCD matter in the core of the star. Specifically, the fast cooling is attributed to an enhancement in the neutrino emission triggered by a transition from a fully gapped, two-flavor, red-green color-superconducting quark condensate to a superconducting crystalline or an alternative gapless, color-superconducting phase. The blue colored condensate is modeled as a Bardeen-Cooper-Schrieffer (BCS)-type color superconductor with spin-one pairing order parameter. We study the sensitivity of the fits to the phase transition temperature, the pairing gap of blue quarks and the time-scale characterizing the phase transition (the latter modelled in terms of a width parameter). Relative variations in these parameter around their best fit values larger than spoil the fit to the data. We confirm the previous finding that the cooling curves show significant variations as a function of compact star mass, which allows one to account for dispersion in the data on the surface temperatures of thermally emitting neutron stars.

    Comments:
    v2: minor clarifications and editorial corrections, added references, version in press. v1: 11 pages, 9 figures, submitted to EPJA 2015 Topical Issue on "Exotic Matter in Neutron Stars"
    Subjects:
    High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); Nuclear Theory (nucl-th)
    arXiv:
    1509.06986 [pdf]
    EPJA(2016)·22 citations

Affiliations

first authorsco-authorsvia INSPIRE