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Nuclear Theory·nucl-th

Monday·November 4, 2024

7 papers—3 primary·4 cross-listed

All7Primary3Cross-lists4
  1. 04

    [Submitted on 31 Oct 2024] (cross-list from hep-ph)

    The quark gap equation in light-cone gauge

    Roberto Correa da Silveira🇧🇷 · Fernando E. Serna🇨🇴 · Bruno El-Bennich🇧🇷

    We calculate the quark self-energy correction in light-cone gauge motivated by distribution amplitudes whose definition implies a Wilson line. The latter serves to preserve the gauge invariance of the hadronic amplitudes and becomes trivial in light-cone gauge. Therefore, the calculation of the distribution amplitudes simplifies significantly provided that wave functions and propagators are obtained in that gauge. In here, we explore the corresponding Dyson-Schwinger equation in its leading truncation and with a dressed vertex derived from a Ward identity in light-cone gauge. The quark's mass and wave renormalization functions, as well as a third complex-valued amplitude, are found to depend on the relative orientation of the quark momentum and a light-like four-vector, which expresses a geometric gauge dependence of the propagator.

    Comments:
    Accepted for publication in PRD. An improved numerical treatment of divergences that occur in the C functions and use of the Cornwall gluon propagator derived in pinch technique lead to revised numerical results. In particular, the C functions in Figs. 3 and 6 are very small or consistent with zero depending on the frame of the quark. The conclusions are barely modified
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2411.00106 [pdf]
    PRD(2025)·0 citations
  2. 05

    [Submitted on 1 Nov 2024] (cross-list from hep-ph)

    Estimate of the -wave scattering length in the isospin-0 channel from Belle and LHCb data

    N. N. Achasov🇷🇺 · G. N. Shestakov🇷🇺

    It is shown that the Belle and LHCb data on the interference of the amplitudes of the and partial waves in the decays and allow us to obtain an estimate of the -wave scattering length in the channel with isospin : fm. The possibility of explaining the found value by the contribution of the resonance is discussed. The decay of is also briefly discussed.

    Comments:
    8 pages
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2411.00377 [pdf]
    PRD(2025)·0 citations
  3. 06

    [Submitted on 1 Nov 2024] (cross-list from nucl-ex)

    Isospin breaking in the Kr and Br mirror system

    A. Algora🇪🇸 · A. Vitéz-Sveiczer🇭🇺 · A. Poves🇪🇸 · G. G. Kiss🇭🇺 · B. Rubio🇪🇸 · G. de Angelis🇮🇹 · F. Recchia🇮🇹 · S. Nishimura🇯🇵 · T. Rodriguez🇪🇸 · P. Sarriguren🇪🇸 · J. Agramunt🇪🇸 · V. Guadilla🇪🇸 and 56 other authors

    Isospin symmetry is a fundamental concept in nuclear physics. Even though isospin symmetry is partially broken, it holds approximately for most nuclear systems, which makes exceptions very interesting from the nuclear structure perspective. In this framework, it is expected that the spins and parities of the ground states of mirror nuclei should be the same, in particular for the simplest systems where a proton is exchanged with a neutron or vice versa. In this work, we present evidence that this assumption is broken in the mirror pair Br and Kr system. Our conclusions are based on a high-statistics decay study of Kr and on state-of-the-art shell model calculations. In our work, we also found evidence of a new state in Se, populated in the -delayed proton emission process which can be interpreted as the long sought coexisting 0 state.

    Comments:
    8 pages with references, 3 figures. Supplemental material 4 pages (1 table, 3 figures)
    Subjects:
    Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2411.00509 [pdf]
    PRL(2025)·6 citations
  4. 07

    [Submitted on 1 Nov 2024] (cross-list from astro-ph.SR)

    Heavy element abundances from a universal primordial distribution

    G. Roepke · D. Blaschke · F. K. Roepke

    We present a freeze-out approach to the formation of heavy elements in expanding nuclear matter. Applying concepts used in the description of heavy-ion collisions or ternary fission, we determine the abundances of heavy elements taking into account in-medium effects such as Pauli blocking and the Mott effect, which describes the dissolution of nuclei at high densities of nuclear matter. With this approach, we search for a universal primordial distribution in an equilibrium state from which the gross structure of the solar abundances of heavy elements freezes out via radioactive decay of the excited states. The universal primordial state is characterized by the Lagrangian parameters of temperature and chemical potentials of neutrons and protons. We show that such a state exists and determine a temperature of 5.266 MeV, a neutron chemical potential of 940.317 MeV and a proton chemical potential of 845.069 MeV, at a baryon number density of 0.013 fm and a proton fraction of 0.13. Heavy neutron-rich nuclei such as the hypothesized double-magic nucleus Sn appear in the primordial distribution and contribute to the observed abundances after fission. We discuss astrophysical scenarios for the realization of this universal primordial distribution for heavy element nucleosynthesis, including supernova explosions, neutron star mergers and the inhomogeneous Big Bang. The latter scenario may be of interest in the light of early massive objects observed with the James Webb Space Telescope and opens new perspectives to explain universality of the observed r-process patterns and the lack of observations of population III stars.

    Comments:
    15 pages, 4 figures, submitted to A&A
    Subjects:
    Solar and Stellar Astrophysics (astro-ph.SR); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
    arXiv:
    2411.00535 [pdf]
    3 citations

Affiliations

first authorsco-authorsvia INSPIRE