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Nuclear Theory·nucl-th

Monday·November 20, 2017

5 papers—2 primary·3 cross-listed

All5Primary2Cross-lists3
  1. 03

    [Submitted on 17 Nov 2017] (cross-list from hep-th)

    D-instantons in Real Time Dynamics

    Si-wen Li🇨🇳 · Shu Lin🇨🇳

    Instanton is known to exist in Euclidean spacetime only. Their role in real time dynamics is usually understood as tunneling effect by Wick rotation. We illustrate other effects of instanton in holography by investigating 5d effective gravity theory of the black D3-brane-D-instanton system. The supergravity description of the D3-brane-D-instanton system is dual to the super Yang-Mills theory with topological excitations of the vacuum. We obtain Euclidean correlators in the presence of instantons by analyzing of the fluctuations of the bulk fields in the 5d effective theory. Furthermore, analytic continuation of Euclidean correlators leads to retarded correlators, which characterize real time dynamics. We find interestingly real time fluctuations of topological charge can destroy instantons and the lifetime of instanton is set by temperature. This implies instanton contribution to "real time dynamics" is suppressed at high temperature, which is analogous to classic field theory results that instanton contribution to "thermodynamics" is suppressed at high temperature.

    Comments:
    29 pages, 3 figures. Added computation details and Sec 4.3 on the justification of analytic continuation. Main results not changed. To appear in PRD
    Subjects:
    High Energy Physics — Theory (hep-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1711.06365 [pdf]
    PRD(2018)·8 citations
  2. 04

    [Submitted on 17 Nov 2017] (cross-list from hep-ph)

    Scattering of charmed baryons on nucleons

    J. Haidenbauer🇩🇪 · G. Krein🇧🇷

    Chiral effective field theory is utilized for extrapolating results on the interaction, obtained in lattice QCD at unphysical (large) quark masses, to the physical point. The pion-mass dependence of the components that constitute the potential up to next-to-leading order (pion-exchange diagrams and four-baryon contact terms) is fixed by information from lattice QCD simulations. No recourse to SU(3) or SU(4) flavor symmetry is made. It is found that the results of the HAL QCD Collaboration for quark masses corresponding to -- MeV imply a moderately attractive interaction at MeV with scattering lengths of fm for the as well as the partial waves. For such an interaction the existence of a charmed counterpart of the hypertriton is unlikely but four- and/or five-baryons systems with a baryon could be indeed bound.

    Comments:
    7 pages, 2 figures; table added, several comments added
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1711.06470 [pdf]
    EPJA(2018)·33 citations
  3. 05

    [Submitted on 17 Nov 2017] (cross-list from astro-ph.HE)

    Reaction rates and transport in neutron stars

    Andreas Schmitt🇬🇧 · Peter Shternin🇷🇺

    Understanding signals from neutron stars requires knowledge about the transport inside the star. We review the transport properties and the underlying reaction rates of dense hadronic and quark matter in the crust and the core of neutron stars and point out open problems and future directions.

    Comments:
    74 pages; commissioned for the book "Physics and Astrophysics of Neutron Stars", NewCompStar COST Action MP1304; version 3: minor changes, references updated, overview graphic added in the introduction, improvements in Sec IV.A.4
    Subjects:
    High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1711.06520 [pdf]
    Astrophys.Space Sci.Libr.(2018)·94 citations

Affiliations

first authorsco-authorsvia INSPIRE