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Nuclear Theory·nucl-th

Friday·October 4, 2024

7 papers—4 primary·3 cross-listed

All7Primary4Cross-lists3
  1. 01

    [Submitted on 2 Oct 2024]

    Role of neutron pairing with density-gradient dependence in the semi-microscopic treatment of the inner crust of neutron stars

    Nicolas Chamel · John-Michael Pearson · Nikolay N. Shchechilin

    Using the fourth-order extended Thomas-Fermi method with Strutinsky-integral shell and pairing corrections, we calculate the inner crust of neutron stars with the BSk31 functional, whose pairing has two terms: i) a term that is fitted to the results of microscopic calculations on homogeneous nuclear matter (accounting for both medium polarization and self-energy effects) that are more realistic than those of our earlier functionals; ii) an empirical term that is dependent on the density gradient, which permits an excellent fit to nuclear masses. Both proton and neutron pairing are taken into account, the former in the BCS theory and the latter in the local density approximation. We found that the equilibrium value of the proton number remains 40 over the entire density range considered, whether or not neutron pairing is included. The new equation of state and the composition are very similar to those of our previously preferred functional, BSk24. However, the predicted neutron pairing fields are quite different. In particular, clusters are found to be impermeable to the neutron superfluid. The implications for the neutron superfluid dynamics are briefly discussed. Since the new pairing is more realistic, the functional BSk31 is better suited for investigating neutron superfluidity in neutron-star crusts.

    Comments:
    16 pages, 13 figures. Accepted for publication in Physical Review C
    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
    arXiv:
    2410.01997 [pdf]
    PRC(2024)·9 citations
  2. 02

    [Submitted on 3 Oct 2024]

    On the extraction of fission mode properties from fragment mass distributions

    Patrick McGlynn · Cedric Simenel

    Background: Fission modes are typically characterised by fragment mass and total kinetic energy centroids, around which a distribution of these variables is observed. These distributions are usually fitted with Gaussian functions. Purpose: To investigate how the properties of these ``Gaussian fission modes'' compare with underlying ``theoretical fission modes'' defined from the potential energy surface of the fissioning nuclei. Methods: A simple approach, inspired by the scission point model, is introduced to investigate the impact of anharmonicity of the potential along the scission line on Gaussian mode properties. This approach is also used to evaluated an ``effective potential'' from the yields. Results: Several Gaussian functions are usually required to fit yields from non-harmonic potentials associated with a unique theoretical mode. Similarly, ``effective fission modes'', defined from the wells of the effective potentials, are sometime very different to the Gaussian modes. For instance, the S1 and S2 Brosa modes contribute to the same effective potential well at scission. Conclusions: Gaussian fits are useful to identify the role of shell effects in fission. However, comparisons with theoretical potential energy surfaces are better carried with effective potentials extracted from the yields, assuming that a broad range of excitation energies is available.

    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2410.02187 [pdf]
    PRC(2025)·3 citations
  3. 03

    [Submitted on 3 Oct 2024]

    Simulating collectivity in dense baryon matter with multiple fluids

    Iurii Karpenko🇨🇿 · Jakub Cimerman🇨🇿 · Pasi Huovinen🇵🇱 · Boris Tomasik🇨🇿

    We report on construction of a modern multi-fluid approach to heavy-ion collisions at FAIR/BES energies (MUFFIN) and show the reproduction of basic experimental observables in Au-Au collisions in the RHIC Beam Energy Scan program. We also show the -differential and -integrated polarization of (anti-) hyperons. In MUFFIN simulations, we observe a strong splitting between polarizations of and anti-. The splitting is driven purely by a finite baryon chemical potential.

    Comments:
    Proceedings of SQM2024, Strasbourg (France), 3-7 June 2024. 4 pages, 3 figures. v2: version accepted for the publication
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    2410.02473 [pdf]
    EPJ Web Conf.(2025)·1 citation
  4. 04

    [Submitted on 3 Oct 2024]

    Accurate calculation of low energy scattering phase shifts of charged particles in a harmonic oscillator trap

    Mirko Bagnarol · Nir Barnea · Matus Rojik · Martin Schafer

    Considering the elastic scattering of two charged particles, we present two methods for numerically solving the generalized Coulomb-corrected BERW formula with high accuracy across the entire energy spectrum. We illustrate these methods using p-alpha scattering, employing a phenomenological p-alpha short-range interaction. Our results reproduce the phase shifts computed with the Numerov method for all l=0 and l=1 channels. We also provide full access to the Python script used to obtain these results, which can be readily applied to a wide range of core-fragment scattering problems in nuclear and atomic physics.

    Comments:
    6 pages, 3 figures
    Subjects:
    Nuclear Theory (nucl-th); physics.chem-ph (physics.chem-ph)
    arXiv:
    2410.02602 [pdf]
    PLB(2025)·5 citations
  5. 05

    [Submitted on 2 Oct 2024] (cross-list from hep-ph)

    Revisiting Single Inclusive Jet Production: Small- Resummation at Next-to-Leading Logarithm

    Kyle Lee🇺🇸 · Ian Moult🇺🇸 · Xiaoyuan Zhang🇺🇸

    The precision description of jet production plays an important role in many aspects of collider physics. In a recent paper we have presented a new factorization theorem for inclusive small radius jet production. The jet function appearing in our factorization theorem exhibits a non-standard renormalization group evolution, which, starting at next-to-leading logarithm (NLL), differs from previous results in the literature. In this paper we perform a first phenomenological study using our newly developed formalism, applying it to compute the spectrum of small radius jets in at NLL. We compare our results with previous predictions, highlighting the numerical impact of previously neglected terms throughout phase space. Our approach can be used for a variety of different collider systems, in particular, and collisions, with broad applications to the jet substructure program. Most importantly, since our factorization theorem is valid to all orders, the approach developed here will enable NNLL resummation of small radius logarithms in inclusive jet production, extending the precision of jet substructure calculations.

    Comments:
    10 pages+appendix, 3 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2410.01902 [pdf]
    17 citations
  6. 06

    [Submitted on 3 Oct 2024] (cross-list from hep-lat)

    Gravitational form factors of glueballs in Yang-Mills theory

    Ryan Abbott🇺🇸 · Daniel C. Hackett🇺🇸 · Dimitra A. Pefkou🇺🇸 · Fernando Romero-López🇨🇭 · Phiala Shanahan🇺🇸

    This work presents preliminary results of the first determination of the energy-momentum tensor form factors of the scalar glueball, referred to as gravitational form factors (GFFs). The calculation has been carried out in lattice Yang-Mills theory at a single lattice spacing. Using variationally optimized operators, the matrix elements are extracted from ratios of three-point functions to two-point functions. The glueball GFFs and their kinematic dependence are compared to those of other hadrons from previous calculations.

    Comments:
    9 pages, 3 figures, Contribution to the 41st International Symposium on Lattice Field Theory, July 28th - August 3rd 2024, Liverpool, UK, v2 Acknowledgments update
    Subjects:
    High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2410.02706 [pdf]
    PoS(2025)·5 citations
  7. 07

    [Submitted on 3 Oct 2024] (cross-list from hep-ph)

    Transverse Energy-Energy Correlator for Vector Boson-Tagged Hadron Production in and collisions

    Zhong-Bo Kang🇺🇸 · Sookhyun Lee🇺🇸 · Jani Penttala🇺🇸 · Fanyi Zhao🇺🇸 · Yiyu Zhou🇺🇸

    We investigate the transverse energy-energy correlator (TEEC) event-shape observable for back-to-back and production in both and collisions. Our study incorporates nuclear modifications into the transverse-momentum dependent (TMD) factorization framework, with resummation up to next-to-leading logarithmic (NLL) accuracy, for TEEC as a function of the variable , where is the azimuthal angle between the vector boson and the final hadron. We analyze the nuclear modification factor in collisions at RHIC and collisions at the LHC. Our results demonstrate that the TEEC observable is a sensitive probe for nuclear modifications in TMD physics. Specifically, the changes in the -distribution shape provide insights into transverse momentum broadening effects in large nuclei, while measurements at different rapidities allow us to explore nuclear modifications in the collinear component of the TMD parton distribution functions in nuclei.

    Comments:
    13 pages, 5 figures
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2410.02747 [pdf]
    PRD(2025)·16 citations

Affiliations

first authorsco-authorsvia INSPIRE