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Nuclear Theory·nucl-th

Wednesday·June 8, 2016

7 papers—5 primary·2 cross-listed

All7Primary5Cross-lists2
  1. 01

    Avoiding common pitfalls and misconceptions in extractions of the proton radius

    Jan C. Bernauer🇺🇸 · Michael O. Distler🇩🇪

    In a series of recent publications, different authors produce a wide range of electron radii when reanalyzing electron proton scattering data. In the light of the proton radius puzzle, this is a most unfortunate situation. However, we find flaws in most analyses that result in radii around 0.84 fm. In this paper, we explain our reasoning and try to illustrate the most common pitfalls.

    nucl-thhep-phnucl-ex16 citations
  2. 02

    Three pion nucleon coupling constants

    E. Ruiz Arriola🇪🇸 · J. E. Amaro🇪🇸 · R. Navarro Perez🇺🇸

    There exist four pion nucleon coupling constants, , , and which coincide when up and down quark masses are identical and the electron charge is zero. While there is no reason why the pion-nucleon-nucleon coupling constants should be identical in the real world, one expects that the small differences might be pinned down from a sufficiently large number of independent and mutually consistent data. Our discussion provides a rationale for our recent determination based on a partial wave analysis of the self-consistent nucleon-nucleon Granada-2013 database comprising 6713 published data in the period 1950-2013.

    nucl-thhep-phnucl-exMod.Phys.Lett.A(2016)·12 citations
  3. 03

    Nambu-Goldstone modes in the random phase approximation

    Kai Neergård

    I show that the kernel of the random phase approximation (RPA) matrix based on a stable Hartree, Hartree-Fock, Hartree-Bogolyubov or Hartree-Fock-Bogolyubov mean field solution is decomposed into a subspace with a basis whose vectors are associated, in the equivalent formalism of a classical Hamiltonian homogeneous of second degree in canonical coordinates, with conjugate momenta of cyclic coordinates (Nambu-Goldstone modes) and a subspace with a basis whose vectors are associated with pairs of a coordinate and its conjugate momentum neither of which enters the Hamiltonian at all. In a subspace complementary to the one spanned by all these coordinates including the conjugate coordinates of the Nambu-Goldstone momenta, the RPA matrix behaves as in the case of a zerodimensional kernel. This result was derived very recently by Nakada as a corollary to a general analysis of RPA matrices based on both stable and unstable mean field solutions. The present proof does not rest on Nakada's general results.

    nucl-thquant-phPTEP(2016)·1 citation
  5. 05

    Three-body scattering problem in the fixed center approximation: the case of attraction

    Alexander E. Kudryavtsev🇷🇺 · Vakhid A. Gani🇷🇺 · Alexander I. Romanov🇷🇺

    We study the scattering of a light particle on a bound pair of heavy particles (e.g., the deuteron) within the fixed center approximation in the case of light-heavy attraction, solving the integral equation for the three-body Green's function both in the coordinate and in the momentum space. The results for the three-body scattering amplitude appear to be ambiguous -- they depend on a single real parameter. This parameter may be fixed by a three-body input, e.g., the three-body scattering length. We also solve the integral equation for the three-body Green function in the momentum space, introducing a finite cut-off. We show that all three approaches are equivalent. We also discuss how our approach to the problem matches with the introduction of three-body contact interaction as done by other authors.

    nucl-thhep-phEPJA(2016)·3 citations
  6. 06

    Quark deconfinement in the proto-magnetar model of Long Gamma-Ray Bursts

    A. G. Pili🇮🇹 · N. Bucciantini🇮🇹 · A. Drago🇮🇹 · G. Pagliara🇮🇹 · L. Del Zanna🇮🇹

    We investigate the possible implications of quark deconfinement on the phenomenology of Long Gamma-Ray Bursts focusing, in particular, on the possibility to describe multiple prompt emission phases in the context of the proto-magnetar model. Starting from numerical models of rotating Hadron Stars and Quark Stars in full general relativity we track the electromagnetic spin-down evolution in both the hadronic and quark phase, linking the two families through conservation of baryon number and angular momentum. We give estimates of the timescales and the energetics involved in the spin-down process deriving, in the relevant spin range, the relation between the initial and the final masses and rotational energies, whenever hadron-quark conversion is possible. We show how the results can be used in relevant astrophysical cases such as the double burst GRB 110709B.

    ↳ astro-ph.HEhep-phnucl-thMNRAS(2016)·28 citations
  7. 07

    Chiral-symmetry breaking and pion structure in the Covariant Spectator Theory

    Elmar P. Biernat🇵🇹 · M. T. Peña🇵🇹 · Franz Gross🇺🇸 · Alfred Stadler🇵🇹 · Emílio Ribeiro🇵🇹

    We introduce a covariant approach in Minkowski space for the description of quarks and mesons that exhibits both chiral-symmetry breaking and confinement. In a simple model for the interquark interaction the quark mass function is obtained and used in the calculation of the pion form factor. We study the effects of the mass function and of the different quark pole contributions on the pion form factor.

    ↳ hep-phnucl-thActa Phys.Polon.Supp.(2016)·1 citation

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