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Nuclear Theory·nucl-th

Thursday·August 23, 2018

7 papers—5 primary·2 cross-listed

All7Primary5Cross-lists2
  1. 01

    [Submitted on 21 Aug 2018]

    Medium polarization effects in 3SD1 spin-triplet pairing

    Wenmei Guo🇨🇳 · Umberto Lombardo🇮🇹 · Peter Schuck🇫🇷

    Stimulated by the still puzzling competition between spin-singlet and spin-triplet pairing in nuclei, the 3SD1 neutron-proton pairing is investigated in the framework of BCS theory of nuclear matter. The medium polarization effects are included in the single particle spectrum and also in the pairing interaction starting from the G-matrix, calculated in the Brueckner-Hartree-Fock approximation. The vertex corrections due to spin and isospin collective excitations of the medium are determined from the Bethe-Salpeter equation in the RPA limit, taking into account the tensor correlations. It is found that the self-energy corrections confine the superfluid state to very low-density, while remarkably quenching the magnitude of the energy gap, while the induced interaction has an attractive effect. The interplay between spin-singlet and spin-triplet pairing is discussed in nuclear matter as well as in finite nuclei.

    Comments:
    9 pages, 4 figures, 34 conferences
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1808.07126 [pdf]
    PRC(2019)·12 citations
  2. 02

    [Submitted on 22 Aug 2018]

    Temperature dependence of nuclear spin-isospin response and beta decay in hot astrophysical environments

    Elena Litvinova🇺🇸 · Caroline Robin🇺🇸 · Herlik Wibowo🇺🇸

    A microscopic approach to the proton-neutron nuclear response is formulated in the finite-temperature relativistic nuclear field theory framework. The approach is based on the meson-nucleon Lagrangian of quantum hadrodynamics and advances the relativistic field theory for spin-isospin response beyond the finite-temperature random phase approximation. The dynamical contribution to the in-medium proton-neutron interaction amplitude is described in a parameter-free way by the coupling between the single nucleons and strongly-correlated particle-hole excitations (phonons) within the newly developed finite-temperature formalism. In this framework we investigate temperature dependence of the Gamow-Teller and spin dipole resonances in the closed-shell nuclei Ca, Ni, and Sn. Broader impacts of their temperature dependence are illustrated for the associated beta decay rates and lifetimes of Ni and Sn in hot astrophysical environments. We found a remarkable sensitivity of the beta decay rates to the enhanced low-energy spin-isospin strength at finite temperature, in particular, to the contribution of the first-forbidden transitions.

    Comments:
    Article: 10 pages, 6 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1808.07223 [pdf]
    PLB(2020)·36 citations
  3. 03

    [Submitted on 22 Aug 2018]

    Tensor optimized Fermi sphere method for nuclear matter -- power series correlated wave function and a cluster expansion

    Taiichi Yamada

    A new formalism, called "tensor optimized Fermi sphere (TOFS) method", is developed to treat the nuclear matter using a bare interaction among nucleons. In this method, the correlated nuclear matter wave function is taken to be a power series type, and an exponential type, , with the uncorrelated Fermi-gas wave function , where the correlation operator can induce central, spin-isospin, tensor, etc.~correlations, and corresponds to a limiting case of (). In the TOFS formalism based on Hermitian form, it is shown that the energy per particle in nuclear matter with can be expressed in terms of a linked-cluster expansion. On the basis of these results, we present the formula of the energy per particle in nuclear matter with . We call the th-order TOFS calculation for evaluating the energy with , where the correlation functions are optimally determined in the variation of the energy. The TOFS theory is applied for the study of symmetric nuclear matter using a central NN potential with short-range repulsion. The calculated results are fairly consistent to those of other theories such as the Brueckner-Hartree-Fock approach etc.

    Comments:
    35 pages, 2 figures: version accepted for publication in Annals of Physics
    Subjects:
    Nuclear Theory (nucl-th); cond-mat.other (cond-mat.other)
    arXiv:
    1808.07257 [pdf]
    Annals Phys.(2019)·8 citations
  4. 04

    [Submitted on 22 Aug 2018]

    Study of the double Gamow-Teller transitions using the shell model approach

    Naftali Auerbach🇮🇱 · Minh-Loc Bui🇮🇱

    The double Gamow-Teller strength distributions in the lightest double beta-decay candidate Ca and its isotope Ca were calculated using the nuclear shell model by applying the single Gamow-Teller operator two times sequentially on the ground state of parent nucleus. The nuclear matrix element of the double Gamow-Teller transition from the ground state to the ground state that goes into the double beta decay calculation was shown as a small fraction of the total transition.

    Comments:
    9 pages, 8 figures, contribution to International Conference Nuclear Structure and Related Topics, Burgas, Bulgaria, June 3-June 9, 2018 (NSRT18)
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1808.07323 [pdf]
    EPJ Web Conf.(2018)·0 citations
  5. 05

    [Submitted on 22 Aug 2018]

    Nuclear shape phase transitions within a correlation between two quantum concepts

    S. Ait Elkorchi🇲🇦 · M. Chabab🇲🇦 · A. El Batoul🇲🇦 · A. Lahbas🇲🇦 · M. Oulne🇲🇦

    We present a correlation that we have revealed, for the first time, between both quantum concepts, namely: the Minimal Length (ML) and the Deformation Dependent Mass (DDM) in transitional nuclei near the critical points symmetries (CPS) X(3) and Z(4). Such a correlation could be considered as a new signature for these CPS. This new signature allowed us to predict new candidate nuclei for these critical points.

    Comments:
    5 pages, 7 figures
    Subjects:
    Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
    arXiv:
    1808.07447 [pdf]
    Nucl.Theor.(2019)·0 citations
  6. 06

    [Submitted on 21 Aug 2018] (cross-list from hep-ph)

    Double charged heavy constituents of dark atoms and superheavy nuclear objects

    Vakhid A. Gani🇷🇺 · Maxim Yu. Khlopov🇷🇺 · Dmitry N. Voskresensky🇷🇺

    We consider the model of composite dark matter assuming stable particles of charge bound with primordial helium nuclei by Coulomb force in He atoms. We study capture of such dark atoms in matter and propose a possibility of existence of stable -enriched superheavy nuclei and -nuclearites, in which heavy -dark matter fermions are bound by electromagnetic forces with ordinary nuclear matter. He atoms accumulation in stars and its possible effect in stellar evolution is also considered, extending the set of indirect probes for composite dark matter.

    Comments:
    15 pages; v2: some changes in the Introduction and Conclusion sections, references added; matches the published version
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Cosmology and Nongalactic Astrophysics (astro-ph.CO); Nuclear Theory (nucl-th)
    arXiv:
    1808.06816 [pdf]
    PRD(2019)·21 citations
  7. 07

    [Submitted on 21 Aug 2018] (cross-list from hep-ph)

    A multiquark approach to excited hadrons and Regge trajectories

    S. S. Afonin🇷🇺

    We propose a novel approach to construction of hadron spectroscopy. The case of light nonstrange mesons is considered. By assumption, all such mesons above 1 GeV appear due to creation of constituent quark-antiquark pairs inside the pi or rho (omega) mesons. These spin-singlet or triplet pairs dictate the quantum numbers of formed resonance. The resulting classification of light mesons turns out to be in a better agreement with the experimental observations than the standard quark model classification. It is argued that the total energy of quark components should be proportional to the hadron mass squared rather than the linear mass. As a byproduct a certain relation expressing the constituent quark mass via the gluon and quark condensate is put forward. We show that our approach leads to an effective mass counting scheme for meson spectrum and results in the linear Regge and radial Regge trajectories by construction. An experimental observation of these trajectories might thus serve as an evidence not for string but for multiquark structure of highly excited hadrons.

    Comments:
    15 pages. arXiv admin note: substantial text overlap with arXiv:1705.01899
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1808.07363 [pdf]
    Adv.High Energy Phys.(2019)·7 citations

Affiliations

first authorsco-authorsvia INSPIRE