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Nuclear Theory·nucl-th

Monday·March 11, 2024

5 papers—3 primary·2 cross-listed

All5Primary3Cross-lists2
  1. 01

    [Submitted on 8 Mar 2024]

    Electrical conductivity and shear viscosity of a pion gas in a thermo-magnetic medium

    Pallavi Kalikotay🇧🇩 · Snigdha Ghosh🇮🇳 · Nilanjan Chaudhuri🇮🇳 · Pradip Roy🇮🇳 · Sourav Sarkar🇮🇳

    We evaluate the electrical conductivity and shear viscosity of a interacting pion gas in a thermo-magnetic medium using the kinetic theory. The collision term of the relativistic Boltzmann transport equation in presence of background magnetic field is solved using the relaxation time approximation. The medium modified relaxation time is obtained from the corresponding in-medium scattering cross-section calculated using the thermo-magnetic propagator. It is observed that the average relaxation time shows a variation with temperature for a fixed value of magnetic field. The relaxation time shows a mild oscillatory variation with respect to the magnetic field. It is also observed that the medium dependent scattering cross-section causes a considerable amount of influence on the electrical conductivity and shear viscosity compared to its vacuum counterpart.

    Comments:
    Version published in EPJA
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2403.05165 [pdf]
    EPJA(2024)·4 citations
  2. 02

    [Submitted on 8 Mar 2024]

    Shape of 12C

    Masaaki Kimura · Yasutaka Taniguchi

    We have examined the hypothesis by Bijker and Iachello who asserted that 12C has an internal structure with three alpha particles arranged in a triangular shape, leading to the formation of the ground rotational band consisting of 0+, 2+, 3-, 4 and 5- states. Following this idea, we reconstructed the intrinsic shape of 12C using experimental electron scattering data with minimal theoretical assumption. Our sole assumption was that the observed 0+, 2+, 3-, and 4+ states share a common internal structure, forming a rotational spectrum. The reconstructed intrinsic density showed a beautiful triangular shape with three peaks implying alpha cluster formation in the ground band.

    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    2403.05287 [pdf]
    EPJA(2024)·4 citations
  3. 03

    [Submitted on 8 Mar 2024]

    Confronting the Lippmann-Schwinger equation and the method for coupled-wave separable potentials

    M.S. Sánchez🇪🇸 · J.A. Oller🇪🇸 · D.R. Entem🇪🇸

    We study a family of separable potentials with and without added contact interactions by solving the associated Lippmann-Schwinger equation with two coupled partial waves. The matching of the resulting amplitude matrix with the effective-range expansion is studied in detail. When a counterterm is included in the potential we also carefully discuss its renormalization. Next, we use the matrix method and study whether the amplitude matrices from the potentials considered admit an representation in matrix form. As a novel result we show that it is typically not possible to find such matrix representation for the coupled partial-wave case. However, a separate representation for each coupled partial wave, a valid option known in the literature, is explicitly implemented and numerically solved in cases where the matrix method is unavailable.

    Comments:
    45 pages, 3 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2403.05486 [pdf]
    Annals Phys.(2024)·1 citation

Affiliations

first authorsco-authorsvia INSPIRE