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Nuclear Theory·nucl-th

Tuesday·March 19, 2024

12 papers—6 primary·6 cross-listed

All12Primary6Cross-lists6
  1. 07

    [Submitted on 15 Mar 2024] (cross-list from hep-ph)

    Quark anomalous magnetic moment in an extreme magnetic background from perturbative QCD

    Eduardo S. Fraga🇧🇷 · Leticia F. Palhares🇧🇷 · Cristian Villavicencio🇨🇱

    We compute the one-loop QCD correction to the photon-quark-antiquark vertex in an extremely strong magnetic background, i.e., one in which is much larger than all other mass scales. We resort to the lowest-Landau level approximation, and consider on shell fermions. We find that the total magnetic moment is such that the anomalous magnetic moment contributes to the electric part , the other contributions to and being completely suppressed. We show results for the anomalous magnetic moment of quarks up and down, scaled by their values in the vacuum, as a function of the external magnetic field, considering dressed gluons and a renormalization scale .

    Comments:
    10 pages, 11 figures, minor corrections. To appear in Phys. Rev. D
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2403.10641 [pdf]
    PRD(2024)·8 citations
  2. 08

    [Submitted on 16 Mar 2024] (cross-list from nucl-ex)

    Evolution of chirality from transverse wobbling in Pr

    N. Sensharma · U. Garg · Q. B. Chen · S. Frauendorf · S. Zhu · J. Arroyo · A. D. Ayangeakaa · D. P. Burdette · M. P. Carpenter · P. Copp · J. L. Cozzi · S. S. Ghugre and 11 other authors

    Chirality is a distinct signature that characterizes triaxial shapes in nuclei. We report the first observation of chirality in the nucleus Pr using a high-statistics Gammasphere experiment with the Sb(O,4n)Pr reaction. Two chiral-partner bands with the configuration have been identified in this nucleus. Angular distribution analyses of the transitions connecting the two bands reveal a dominant dipole character, and quasiparticle triaxial rotor model calculations show good agreement with the data. Since the simultaneous observation of chirality and transverse wobbling in Pr relies critically on these angular distribution results, we also address and refute the experimental and theoretical criticisms raised in a recent work by Lv et al., presenting additional evidence that further strengthens our interpretation. This marks the first observation of both hallmarks of triaxiality-chirality and wobbling-in the same nucleus.

    Comments:
    17 pages, 13 figures
    Subjects:
    Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2403.10749 [pdf]
    PRC(2026)·2 citations
  3. 09

    [Submitted on 17 Mar 2024] (cross-list from nucl-ex)

    Revisiting the excitation of the low-lying Ta isomer in optical laser-generated plasma

    Simone Gargiulo · Ivan Madan · Benoit Truc · Paolo Usai · Kjeld Beeks · Veronica Leccese · Giovanni Maria Vanacore · Fabrizio Carbone

    The excitation of the Ta isomer in the laser-plasma scenario was claimed to have been observed more than two decades ago. However, the reported experimental findings - and the respective high excitation rate - were later questioned as they could not be reproduced theoretically. The controversy has remained open ever since. In this work, we reinvestigate both theoretically and experimentally the Ta nuclear excitation in an optical laser-generated plasma. Experimentally we have found no evidence for such an excitation process as consistently predicted by previous and our theoretical models.

    Comments:
    There is an issue with references. Arxiv makes them appear twice
    Subjects:
    Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2403.11280 [pdf]
    PRL(2024)·4 citations
  4. 10

    [Submitted on 18 Mar 2024] (cross-list from astro-ph.HE)

    Detecting superfluid transition in the pulsar core

    Partha Bagchi (1) · Biswanath Layek (2) · Dheeraj Saini (3) · Anjishnu Sarkar (3) · Ajit M. Srivastava (4) · Deepthi Godaba Venkata (2) ((1) School of Physical Sciences, National Institute of Science Education and Research, Bhubaneswar, India, (2) Department of Physics, Birla Institute of Technology and Science, Pilani-333031, India, (3) Physics Department, The LNM Institute of Information Technology, Jaipur-302031, India, (4) Institute of Physics, Sachivalaya Marg, Bhubaneswar-751005, India)

    It is believed that the core of a neutron star can be host to various novel phases of matter, from nucleon superfluid phase to exotic high baryon density quantum chromodynamics (QCD) phases. Different observational signals for such phase transitions have been discussed in the literature. Here, we point out a unique phenomenon associated with phase transition to a superfluid phase, which may be the nucleon superfluid phase or a phase like the CFL phase, allowing for superfluid vortices. In any superfluid phase transition, a random network of vortices forms via the so-called Kibble-Zurek mechanism, which eventually mostly decays away, finally leaving primarily vortices arising from the initial angular momentum of the core. This transient, random vortex network can have a non-zero net angular momentum for the superfluid component, which will generally be oriented in an arbitrary direction. This is in contrast to the final vortices, which arise from initial rotation and hence have the initial angular momentum of the neutron star. The angular momentum of the random vortex network is balanced by an equal and opposite angular momentum in the normal fluid due to the conservation of angular momentum, thereby imparting an arbitrarily oriented angular momentum component to the outer shell of the neutron star. This will affect the pulse timing and pulse profile of a pulsar. These changes in the pulses will decay away in a characteristic manner such that the random vortex network decays, obeying specific scaling laws leading to universal features for the detection of superfluid transitions occurring in a pulsar core.

    Comments:
    9 pages, no figures
    Subjects:
    High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2403.11539 [pdf]
    MNRAS(2024)·2 citations
  5. 11

    [Submitted on 18 Mar 2024] (cross-list from hep-ph)

    Nonlinear Pulse Dynamics in a Magnetized and Nonextensive Quark-Gluon Plasma

    Trambak Bhattacharyya · Md Hasanujjaman

    We investigate the propagation of nonlinear energy density waves in a nonextensive quark-gluon plasma under the influence of a magnetic field using the reductive perturbation technique. For a nonextensive MIT bag equation of state, we obtain the governing equation for the first order perturbation of the energy density. We observe that an increase in the strength of the magnetic field results in the localization of the waves.

    Comments:
    15 pages, 6 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
    arXiv:
    2403.11630 [pdf]
    0 citations
  6. 12

    [Submitted on 18 Mar 2024] (cross-list from hep-ph)

    Isotropization of a longitudinally expanding system of scalar fields in the 2PI formalism

    François Gelis🇫🇷 · Sigtryggur Hauksson🇫🇷

    Motivated by isotropization of QCD matter in the initial stages of heavy-ion collisions, we consider a system of scalar fields that undergoes a boost invariant longitudinal expansion. We use the framework of the two-particle irreducible (2PI) effective action, which is close to the underlying quantum field theory, and resum self-energy corrections up to three loops. The resulting 2PI equations of motion are expressed in terms of the Milne coordinates to account for longitudinal expansion. By solving numerically these equations of motion, we can extract the occupation density and the effective mass generated by in-medium interactions. At the largest values of the coupling considered in this study, we observe the onset of isotropization both in the occupation number and in the momentum dependence of the effective mass.

    Comments:
    39 pages, 11 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2403.11908 [pdf]
    JHEP(2024)·5 citations

Affiliations

first authorsco-authorsvia INSPIRE