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Nuclear Theory·nucl-th

Friday·October 20, 2017

7 papers—4 primary·3 cross-listed

All7Primary4Cross-lists3
  1. 01

    [Submitted on 18 Oct 2017]

    Fundamental Physics with Electroweak Probes of Nuclei

    Saori Pastore🇺🇸

    The past decade has witnessed tremendous progress in the theoretical and computational tools that produce our understanding of nuclei. A number of microscopic calculations of nuclear electroweak structure and reactions have successfully explained the available experimental data, yielding a complex picture of the way nuclei interact with electroweak probes. This achievement is of great interest from the pure nuclear-physics point of view. But it is of much broader interest too, because the level of accuracy and confidence reached by these calculations opens up the concrete possibility of using nuclei to address open questions in other sub-fields of physics, such as, understanding the fundamental properties of neutrinos, or the particle nature of dark matter. In this talk, I will review recent progress in microscopic calculations of electroweak properties of light nuclei, including electromagnetic moments, form factors and transitions in between low-lying nuclear states along with preliminary studies for single- and double-beta decay rates. I will illustrate the key dynamical features required to explain the available experimental data, and, if time permits, present a novel framework to calculate neutrino-nucleus cross sections for nuclei.

    Comments:
    5 pages, 3 figures, proceedings of The 12th International Spring Seminar on Nuclear Physics 'Current Problems and Prospects for Nuclear Structure', Sant'Angelo d'Ischia, May 15 to 19, 2017
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1710.06870 [pdf]
    J.Phys.Conf.Ser.(2018)·0 citations
  2. 02

    [Submitted on 19 Oct 2017]

    A new ground-state band level energy formula for transitional nuclei

    Shuifa Shen · Jing Pan · Yupeng Yan · Jiejie Shen · Feipeng Wang · Tingtai Wang · Jiaming Jiang · Jing Song · Mengyun Cheng · Lijuan Hao

    A new three parameter formula is proposed for ground-state bands in even-even soft rotors or called transitional nuclei. The new formula blends those of very soft nuclei and well deformed nuclei. Especially, it is found in fact that the formula proposed by P. von Brentano et al. can be derived from our formula if some approximations are adopted and it can be explained why in their work the energy-dependent term beta*E can be dropped. Compared to their formula it can be resulted in that the range of validity of our formula will be much broader than theirs.

    Comments:
    8 pages
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1710.06986 [pdf]
    0 citations
  3. 03

    [Submitted on 17 Oct 2017]

    Historical perspective and future prospects for nuclear interactions

    R. Machleidt🇺🇸

    The nuclear force is the heart of nuclear physics and, thus, the significance of this force for all of nuclear physics can hardly be overstated. Research on this crucial force has by now spanned eight decades and we are still not done. I will first review the rich history of hope and desperation, which had spin-off far beyond just nuclear physics. Next, I will present the current status in the field which is charcterized by the application of an effective field theory (EFT) that is believed to represent QCD in the low energy regime typical for nuclear physics. During the past two decades, this EFT has become the favorite vehicle to derive nuclear two- and many-body forces. Finally, I will take a look into the future: What developments can we expect from the next decades? Will the 30-year cycles of new and "better" ideas for efficiently describing nuclear forces go on for ever, or is there hope for closure?

    Comments:
    38 pages, 15 figures. arXiv admin note: substantial text overlap with arXiv:1608.05978, arXiv:1105.2919
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    1710.07215 [pdf]
    IJMPE(2017)·49 citations
  4. 04

    [Submitted on 19 Oct 2017]

    Varying the chiral magnetic effect relative to flow in a single nucleus-nucleus collision

    Hao-jie Xu🇨🇳 · Jie Zhao🇺🇸 · Xiaobao Wang🇨🇳 · Hanlin Li🇨🇳 · Zi-Wei Lin🇨🇳 · Caiwan Shen🇨🇳 · Fuqiang Wang🇨🇳

    We propose a novel method to search for the chiral magnetic effect (CME) in heavy ion collisions. We argue that the relative strength of the magnetic field (mainly from spectator protons and responsible for the CME) with respect to the reaction plane and the participant plane is opposite to that of the elliptic flow background arising from the fluctuating participant geometry. This opposite behavior in a single collision system, hence with small systematic uncertainties, can be exploited to extract the possible CME signal from the flow background. The method is applied to the existing data at RHIC, the outcome of which is discussed.

    Comments:
    7 Revtex pages, 3 figures. Accepted by Chinese Physics C
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    1710.07265 [pdf]
    CPC(2018)·80 citations
  5. 05

    [Submitted on 18 Oct 2017] (cross-list from astro-ph.HE)

    Fermionic Light Dark Matter particles and the New Physics of Neutron Stars

    M. Cermeño🇪🇸 · M. Ángeles Pérez-García🇪🇸 · Joseph Silk🇫🇷

    Dark Matter constitutes most of the matter in the presently accepted cosmological model for our Universe. The extreme conditions of ordinary baryonic matter, namely high density and compactness, in Neutron Stars make these objects suitable to gravitationally accrete such a massive component provided interaction strength between both, luminous and dark sectors, at current experimental level of sensitivity. We consider several different DM phenomenological models from the myriad of those presently allowed. In this contribution we review astrophysical aspects of interest in the interplay of ordinary matter and a fermionic light Dark Matter component. We focus in the interior nuclear medium in the core and external layers, i.e. the crust, discussing the impact of a novel dark sector in relevant stellar quantities for (heat) energy transport such as thermal conductivity or emissivities.

    Comments:
    12 pages, 7 figures, 1 table. Review contribution
    Subjects:
    High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1710.06866 [pdf]
    Publ.Astron.Soc.Austral.(2017)·21 citations
  6. 06

    [Submitted on 19 Oct 2017] (cross-list from hep-ph)

    Investigating thermalization of a strongly interacting non-Abelian plasma

    L. Bellantuono🇵🇱 · P. Colangelo🇮🇹 · F. De Fazio🇮🇹 · F. Giannuzzi🇮🇹 · S. Nicotri🇮🇹

    Using gauge/gravity duality methods, we study the relaxation towards equilibrium of strongly interacting non-Abelian matter. We adopt boundary sourcing to drive the system out-of-equilibrium, and analyze the equilibration process through local probes (energy density and pressures) and nonlocal probes (lengths of the geodesics between two boundary points and extremal surfaces having a Wilson loop as contour on the boundary). We also investigate the real-time dissociation of the heavy quarkonium in the out-of-equilibrium plasma. Systematic comparison with the results of a geometry dual to viscous hydrodynamics sheds light on the thermalization process.

    Comments:
    6 pages, 7 figures. Talk given at EPS-HEP 2017, European Physical Society conference on High Energy Physics
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
    arXiv:
    1710.07044 [pdf]
    PoS(2017)·0 citations
  7. 07

    [Submitted on 19 Oct 2017] (cross-list from hep-ph)

    Coupled kinetic equations for quarks and gluons in the relaxation time approximation

    Wojciech Florkowski🇵🇱 · Ewa Maksymiuk🇵🇱 · Radoslaw Ryblewski🇵🇱

    Kinetic equations for quarks and gluons are solved numerically in the relaxation time approximation for the case of one-dimensional boost-invariant geometry. Quarks are massive and described by the Fermi-Dirac statistics, while gluons are massless and obey Bose-Einstein statistics. The conservation laws for the baryon number, energy, and momentum lead to two Landau matching conditions which specify the coupling between the quark and gluon sectors and determine the proper-time dependence of the effective temperature and baryon chemical potential of the system. The numerical results illustrate how a non-equlibrium mixture of quarks and gluons approaches hydrodynamic regime described by the Navier-Stokes equations with appropriate forms of the kinetic coefficients. The shear viscosity of a mixture is the sum of the shear viscosities of quark and gluon components, while the bulk viscosity is given by the formula known for a gas of quarks, however, with the thermodynamic variables characterising the mixture. Thus, we find that massless gluons contribute in a non-trivial way to the bulk viscosity of a mixture, provided quarks are massive. We further observe the hydrodynamization effect which takes place earlier in the shear sector than in the bulk one. The numerical studies of the ratio of the longitudinal and transverse pressures show, to a good approximation, that it depends on the ratio of the relaxation and proper times only. This behaviour is connected with the existence of an attractor solution for conformal systems.

    Comments:
    52 pages
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1710.07095 [pdf]
    PRC(2018)·46 citations

Affiliations

first authorsco-authorsvia INSPIRE