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Nuclear Theory·nucl-th

Tuesday·December 3, 2024

20 papers—6 primary·14 cross-listed

All20Primary6Cross-lists14
  1. 01

    [Submitted on 27 Nov 2024]

    In Search of Truth: In memory of Balraj Singh

    José Nicolás Orce · Boris Pritychenko · Tibor Kibédi · Jun Chen

    Born in Punjab (India) in December 1941, Balraj Singh is not only the single most prolific nuclear data evaluator and disseminator of nuclear structure and decay data with 148 evaluations in Nuclear Data Sheets -- 85 as the first and often only author -- plus other journals, but his upmost curiosity and dedication brought him to be one of the finest nuclear physicists, with an everlasting influence on many of us. Balraj passed away about a year ago on 9 October 2023 in Ottawa, Ontario (Canada) at the age of 81, and at Atomic Data and Nuclear Data Tables we would like to commemorate some of his scientific achievements.

    Comments:
    2 pages, 1 figure
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex); History and Philosophy of Physics (physics.hist-ph)
    arXiv:
    2412.00097 [pdf]
    Atom.Data Nucl.Data Tabl.(2025)·0 citations
  2. 02

    [Submitted on 28 Nov 2024]

    Induced three-neutron interactions with low cutoffs for dilute neutron matter

    Viswanathan Palaniappan🇮🇳 · S. Ramanan🇮🇳 · Michael Urban🇮🇳

    The properties of dilute neutron matter are mostly determined by the s-wave two-body (2N) interaction, while three-body (3N) interactions are suppressed by the Pauli principle. In a previous work, we showed that it can be advantageous to use renormalization group based effective interactions with cutoffs scaled with the Fermi momentum, especially at low densities. In that case, induced 3N interactions may become important. In this work, we compute the 3N interaction induced by the similarity renormalization group flow of the s-wave 2N interaction. We work in the momentum-space hyperspherical partial wave basis and investigate its convergence properties. Then we study the effect of the induced 3N interaction on the equation of state of dilute neutron matter. We observe that the cutoff dependence of the equation of state is strongly reduced when the effect of induced 3N interaction is included.

    Comments:
    13 pages, 11 figures. Added one new figure and improved discussions
    Subjects:
    Nuclear Theory (nucl-th); Solar and Stellar Astrophysics (astro-ph.SR); Quantum Gases (cond-mat.quant-gas)
    arXiv:
    2412.00137 [pdf]
    PRC(2025)·4 citations
  3. 03

    [Submitted on 1 Dec 2024]

    Self-consistent microscopic calculations for electron captures on nuclei in core-collapse supernovae

    A. Ravlić · S. Giraud · N. Paar · R. G. T. Zegers

    Calculations for electron capture rates on nuclei with atomic numbers between and are performed in a self-consistent finite-temperature covariant energy density functional theory within the relativistic quasiparticle random-phase approximation. Electron captures on these nuclei contribute most to reducing the electron fraction during the collapse phase of core-collapse supernovae. The rates include contributions from allowed (Gamow-Teller) and first-forbidden (FF) transitions, and it is shown that the latter become dominant at high stellar densities and temperatures. Temperature-dependent effects such as Pauli unblocking and transitions from thermally excited states are also included. The new rates are implemented in a spherically symmetric 1D simulation of the core-collapse phase. The results indicate that the increase in electron capture rates, due to inclusion of FF transitions, leads to reductions of the electron fraction at nuclear saturation density, the peak neutrino luminosity, and enclosed mass at core bounce. The new rates reaffirm that the most relevant nuclei for the deleptonization situate around the and shell closures, but compared to previous simulations, nuclei are less proton rich. The new rates developed in this work are available, and will be of benefit to improve the accuracy of multi-dimensional supernova simulations.

    Comments:
    6 pages, 4 figures, version accepted in PRC Letter
    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR)
    arXiv:
    2412.00650 [pdf]
    PRC(2025)·3 citations
  4. 04

    [Submitted on 1 Dec 2024]

    Ab-initio Approach for Constructing Inverse Potentials for Resonant States of {\alpha}-3H and {\alpha}-3He Scattering

    Ishwar Kant · Ayushi Awasthi · Arushi Sharma · Shikha Awasthi · O.S.K.S. Sastri · M.R. Ganesh Kumar

    In this paper, the inverse potentials for the resonant f states of {\alpha}-3H and {\alpha}-3He are constructed using the phase function method by utilizing an ab-initio approach. A combination of three Morse functions are joined smoothly to prepare the reference potential. While the regular Morse function captures the nuclear and Coulomb interactions at short and medium ranges, an inverse Morse function is chosen to obtain the Coulomb barrier that arises because of the long-range Coulomb interaction. This reference potential is representative of a large family of curves consisting of eight distinct model parameters and two intermediate points that define the boundaries that exist between the three regions. The phase equation is solved using the Runge-Kutta 5th order method for the input reference potential to obtain the scattering phase shifts at various center of mass energies. The model parameters are then adjusted using the genetic algorithm in an iterative fashion to minimize the mean square error between the simulated and expected phase shift values. Our approach successfully constructed the inverse potentials for the resonant f states of the {\alpha}-3H and {\alpha}-3He systems, achieving convergence with a minimized mean square error. The resonance energies and widths for the {\alpha}-3H system for the f-5/2 and f-7/2 states are determined to be [4.19 (4.14), 1.225 (0.918)] MeV and [2.20 (2.18), 0.099 (0.069)] MeV, respectively. For the f-5/2 and f-7/2 states of the {\alpha}-3He system, the resonance energies and widths are [5.03 (5.14), 1.6 (1.2)] MeV and [2.99 (2.98), 0.182(0.175)] MeV, respectively. Our ab-initio approach to solve the phase equation utilizing a combination of smoothly joined Morse functions effectively captures both short-range nuclear and long-range Coulomb interactions, providing an accurate model for nuclear scattering involving charged particles.

    Comments:
    14 pages, 5 figures, 5 tables
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2412.00824 [pdf]
    Phys.Scripta(2025)·2 citations
  5. 05

    [Submitted on 2 Dec 2024]

    Exploring the impact of -isobars on Neutron Star

    Rashmita Jena🇮🇳 · S.K. Biswal🇮🇳 · Padmalaya Dash🇮🇳 · R.N. Panda🇮🇳 · M. Bhuyan🇮🇳

    We include the -isobars in the equation of state (EOS) of neutron star (NS) and study its effects with various parameter sets of the RMF model. We compare our results with the NS's constraints from the mass-radius measurement of PSR J0348+0432, PSR J1614-2230, PSR J0030+0451, PSR J0740+6620, PSR J0952-0607, and tidal deformability of GW170817. We calculate the mass-radius profile and tidal deformabilities of the NS using 21 parameter sets of the RMF model.Analyzing the result with various parameters, it is clear that only few parameter sets can satisfy simultaneously the constraints from NICER and GW170817. NLD parameter set satisfy all the constraints of NICER and GW170817. For its strong predictive power for the bulk properties of the neutron star, we take NLD parameter set as a representative for the detailed calculation of effect of -isobar on neutron star properties. We demonstrate that it is possible that -isobar can produce at 2-3 times the saturation density by adjusting the coupling constants , and in an appropriate range. Bulk properties of the NS like mass-radius profile and tidal deformability is strongly affected by the interaction strength of -isobar. Our calculation shows that it is also possible that by choosing , and to a suitable range the threshold density of -isobar become lower than hyperon. For a particular value of -coupling constants, the decrease by 1.7 km. This manuscipt give an argumentative justification for allowing -isobar degrees of freedom in the calculation of the NS properties.

    Comments:
    9 pages, 10 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2412.01201 [pdf]
    IJMPE(2025)·2 citations
  6. 06

    [Submitted on 2 Dec 2024]

    Simultaneous explanation of XTE J1814-338 and HESS J1731-347 objects using and condensates

    M. Veselsky🇨🇿 · V. Petousis🇨🇿 · P.S. Koliogiannis🇭🇷 · Ch.C. Moustakidis🇬🇷 · J. Leja🇸🇰

    The recent observation of the compact star XTE J1814-338 with a mass of and a radius of km, together with the HESS J1731-347, which has a mass of and a radius of km, shows they provide evidence for the possible presence of exotic matter in the core of neutron stars and significantly enhance our understanding of the equation of state for the dense nuclear matter. In the present study, we investigate the possible existence of negative charged kaons and neutral anti-kaons in neutron stars by employing the relativistic mean field model with first order kaonic ( and ) condensates. To the best of our knowledge, this represents a first alternative attempt aimed to explain the bulk properties of the XTE J1814-338 object and at the same time the HESS J1731-347 object, using a mixture of kaons condensation in dense nuclear matter. In addition, we compare our analysis approach with the recent observation of PSR J0437-4715 and PSR J1231-1411 pulsars, proposing that to simultaneously explain the current variety of astrophysical objects, it is essential to resurrect a scenario of two distinct branches, each corresponding to a different composition of nuclear matter.

    Comments:
    v1: 4 pages, 3 figures. v2: 4 pages, 3 figures, updated text and references; accepted for publication in Physical Review D
    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); Solar and Stellar Astrophysics (astro-ph.SR); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2412.01426 [pdf]
    PRD(2025)·11 citations

Affiliations

first authorsco-authorsvia INSPIRE