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Nuclear Theory·nucl-th

Tuesday·June 6, 2017

13 papers—9 primary·4 cross-listed

All13Primary9Cross-lists4
  1. 10

    [Submitted on 4 Jun 2017] (cross-list from hep-ph)

    Point-Particle Effective Field Theory III: Relativistic Fermions and the Dirac Equation

    C.P. Burgess🇨🇦 · Peter Hayman🇨🇦 · Markus Rummel🇨🇦 · Laszlo Zalavari🇨🇦

    We formulate point-particle effective field theory (PPEFT) for relativistic spin-half fermions interacting with a massive, charged finite-sized source using a first-quantized effective field theory for the heavy compact object and a second-quantized language for the lighter fermion with which it interacts. This description shows how to determine the near-source boundary condition for the Dirac field in terms of the relevant physical properties of the source, and reduces to the standard choices in the limit of a point source. Using a first-quantized effective description is appropriate when the compact object is sufficiently heavy, and is simpler than (though equivalent to) the effective theory that treats the compact source in a second-quantized way. As an application we use the PPEFT to parameterize the leading energy shift for the bound energy levels due to finite-sized source effects in a model-independent way, allowing these effects to be fit in precision measurements. Besides capturing finite-source-size effects, the PPEFT treatment also efficiently captures how other short-distance source interactions can shift bound-state energy levels, such as due to vacuum polarization (through the Uehling potential) or strong interactions for Coulomb bound states of hadrons, or any hypothetical new short-range forces sourced by nuclei.

    Comments:
    29 pages plus appendices, 3 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
    arXiv:
    1706.01063 [pdf]
    JHEP(2017)·16 citations
  2. 11

    [Submitted on 5 Jun 2017] (cross-list from astro-ph.HE)

    Nonlinear approach to the entrainment matrix of superfluid nucleon mixture at zero temperature

    Lev B. Leinson

    The superfluid drag effect, in hydrodynamics of pulsating neutron stars, is conventionally described with the aid of the entrainment matrix relating the mass currents with the velocities of superfluid flows in the system. Equations for the entrainment matrix of a superfluid mixture of neutrons and protons are derived with allowance for the strong dependence of the energy gaps on the velocities of superfluid flows. The calculations are carried out in the frame of the Fermi-liquid theory. The equations obtained are highly nonlinear. Numerical solutions to the equations for some typical cases demonstrate that the components of the entrainment matrix possess a highly nonlinear dependence on the velocities of the two superflows simultaneously. This effect, previously ignored, can greatly influence the dynamics of neutron stars.

    Comments:
    14 pages, 5 figures, Accepted for publication in MNRAS
    Subjects:
    High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
    arXiv:
    1706.01272 [pdf]
    MNRAS(2017)·10 citations
  3. 12

    [Submitted on 5 Jun 2017] (cross-list from hep-lat)

    Parton Distribution Function with Non-perturbative Renormalization from Lattice QCD

    Jiunn-Wei Chen🇹🇼 · Tomomi Ishikawa🇨🇳 · Luchang Jin🇺🇸 · Huey-Wen Lin🇺🇸 · Yi-Bo Yang🇺🇸 · Jian-Hui Zhang🇩🇪 · Yong Zhao🇺🇸

    We present lattice results for the isovector unpolarized parton distribution with nonperturbative RI/MOM-scheme renormalization on the lattice. In the framework of large-momentum effective field theory (LaMET), the full Bjorken- dependence of a momentum-dependent quasi-distribution is calculated on the lattice and matched to the ordinary lightcone parton distribution at one-loop order, with power corrections included. The important step of RI/MOM renormalization that connects the lattice and continuum matrix elements is detailed in this paper. A few consequences of the results are also addressed here.

    Comments:
    11 pages, 6 figures, version accepted by Phys. Rev. D
    Subjects:
    High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    1706.01295 [pdf]
    PRD(2018)·176 citations
  4. 13

    [Submitted on 1 Jun 2017] (cross-list from physics.data-an)

    Identity Method Revisited

    Claude A. Pruneau🇺🇸

    We discuss the impact of finite particle losses associated with instrumental effects in measurements of moments of produced multiplicities with the Identity Method towards the evaluation of fluctuation measures such as . We show that the identity method remains applicable provided it is modified to determine factorial moments , rather than moments . We further show that remains robust if detection efficiencies are uniform across the measurement's acceptance. The robustness is lost, however, if detection efficiencies are momentum dependent, although the identity methods remains applicable provided detection efficiencies can be determined with sufficient accuracy.

    Comments:
    11 pages, 0 figures
    Subjects:
    Data Analysis, Statistics and Probability (physics.data-an); Nuclear Theory (nucl-th)
    arXiv:
    1706.01333 [pdf]
    PRC(2017)·8 citations

Affiliations

first authorsco-authorsvia INSPIRE