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Nuclear Theory·nucl-th

Thursday·August 8, 2024

12 papers—6 primary·6 cross-listed

All12Primary6Cross-lists6
  1. 01

    [Submitted on 6 Aug 2024]

    Neutrinoless decay nuclear matrix elements complete up to NLO in heavy nuclei

    Daniel Castillo🇪🇸 · Lotta Jokiniemi🇨🇦 · Pablo Soriano🇪🇸 · Javier Menéndez🇪🇸

    We evaluate all nuclear matrix elements (NMEs) up to next-to-next-to leading order (NLO) in chiral effective field theory (EFT) for the neutrinoless double-beta () decay of the nuclei most relevant for experiments, including Ge, Mo, and Xe. We use the proton-neutron quasiparticle random-phase approximation (pnQRPA) and the nuclear shell model to calculate the NLO NMEs from very low-momentum (ultrasoft) neutrinos and from loop diagrams usually neglected in studies. Our results indicate that the overall NLO contribution is centered around - for the shell model and - for the pnQRPA, with sizable uncertainties due to the scale dependence of the ultrasoft NMEs and the short-range nature of the loop NMEs. The sign discrepancy between many-body methods is common to all studied nuclei and points to the different behaviour of the intermediate states of the decay. Within uncertainties, our results for the ultrasoft NME are of similar size as contributions usually referred to as ``beyond the closure approximation''.

    Comments:
    10 pages, 4 figures, and 2 tables. Corrected a typo in Eq. (6)
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    2408.03373 [pdf]
    PLB(2025)·19 citations
  2. 02

    [Submitted on 7 Aug 2024]

    Effect of neutrino electromagnetic properties on the quasielastic neutral-current neutrino-nucleus scattering

    K. S. Kim🇰🇷 · P. T. P. Hutauruk🇰🇷 · Seung-il Nam🇰🇷 · Chang Ho Hyun🇰🇷

    In the quasielastic region, we investigate the effect of neutrino electromagnetic properties constrained from the recent experiments on the electroweak neutral current reaction process of the neutrino-C scattering. For a relativistic description of the nuclear dynamics, we employ the relativistic mean-field model, which has been proven to describe the data nicely in the quasielastic region. In the present work, we analyze the influence beyond the Standard Model by considering the neutrino magnetic and electric dipole form factors and charge radius on the neutrino electroweak interactions within C. To this end, we use the values of the neutrino charge radius and the magnetic moment at the squared four momentum transfer obtained from the recent experiments and calculate the neutrino differential cross section of the neutrino-C scattering. We find that the effect of the charge radius and the electric dipole form factor is very small, but the role of the magnetic dipole form factor is sensitive to and becomes sizable at small momentum transfer.

    Comments:
    15 pages, 4 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2408.03493 [pdf]
    CPC(2025)·0 citations
  3. 03

    [Submitted on 7 Aug 2024]

    The Wood-Saxon proton optical potential for p-nuclei

    Sukhendu Saha · Dipali Basak · Chinmay Basu

    A phenomenological mass-energy dependent proton optical model potential has been computed for p-nuclei. The parameters of the Wood-Saxon optical potential are found to be a good fit for proton elastic scattering data involving p-nuclei and elements with mass numbers near p-nuclei (within the range of 74 < A < 148) at energies around the Coulomb barrier of the system. The elastic scattering data were meticulously fitted using the SFRESCO code, allowing for the calculation of the real and imaginary parts of the Wood Saxon optical potential. To validate the model, experimental proton capture cross-sections for 106Cd and 113In near the Coulomb barrier were compared with results obtained using the TALYS-1.96 code, showing better agreement than the available global proton optical model potential.

    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2408.03697 [pdf]
    EPJ Web Conf.(2025)·1 citation
  4. 04

    [Submitted on 7 Aug 2024]

    Feasibility of dark matter admixed neutron star based on recent observational constraints

    Prashant Thakur🇮🇳 · Tuhin Malik🇵🇹 · Arpan Das🇮🇳 · T. K. Jha🇮🇳 · B. K. Sharma🇮🇳 · Constança Providência🇵🇹

    The equation of state (EOS) for neutron stars is modeled using the Relativistic Mean Field (RMF) approach with a mesonic nonlinear (NL) interaction, a modified sigma cut potential (NL- cut), and the influences of dark matter in the NL (NL DM). Using a Bayesian analysis framework, we evaluate the plausibility and impact of each scenario. Experimental constraints on the general properties of finite nuclei and heavy ion collisions, along with astrophysical observational data on neutron star radii and tidal deformation, have been taken into account. It was shown that all models, including the PREX-II data, were less favored, indicating that this experimental data seemed to be in tension with the other constraints included in the inference procedure, and were incompatible with chiral effective field theoretical calculations of pure neutron matter. Considering the models with no PREX-II constraints, we find the model NL- cut with the largest Bayes evidence, indicating that the constraints considered favor the stiffening of the EOS at large densities. Conversely, the neutron star with a dark matter component is the least favorable case in light of recent observational constraints, among different scenarios considered here. The and modes were calculated within the Cowling approximation, and it can be seen that modes are sensitive to the EOS. An analysis of the slopes of the mass-radius curves and -mode mass curves has indicated that these quantities may help distinguish the different scenarios.We also analyzed the impact of new PSR J0437-4715 measurements on neutron star mass-radius estimates, noting a 0.2 km reduction in the 90\% CI upper boundary across all models and a significant Bayes evidence decrease, indicating potential conflicts with previous data or the necessity for more adaptable models.

    Comments:
    18 pages, 10 figures and 6 tables
    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2408.03780 [pdf]
    Astron.Astrophys.(2025)·25 citations
  5. 05

    [Submitted on 7 Aug 2024]

    Nucleon-quark mixed matter and neutron star EOS

    Y. Yamamoto🇯🇵 · N. Yasutake🇯🇵 · Th. A. Rijken🇯🇵

    The nucleon-quark mixed matter is defined in the Brueckner-Hartree-Fock framework, in which quark densities are determined by equilibrium conditions between nucleon and quark chemical potentials, and nucleon-quark interactions play critical roles for resulting EoSs (equation of state). The two models of EoSs are derived from the nucleon-quark mixed matter (NQMM): The NQMM-A EoSs are based on the simple assumption that nucleons and free quarks occupy their respective Fermi levels and their Fermi spheres overlap from each other. In NQMM-B EoSs, the quark Fermi repulsion effect is incorporated on the basis of quakyonic matter, meaning that the nucleon Fermi levels are pushed up from the quark Fermi sphere by the Pauli exclusion principle. For the NQMM-A EoSs, the neutron-star mass-radius () curves are pushed up above the region of and 12.5 km indicated by the recent observations, as the repulsions increase. For the NQMM-B EoSs, the similar results are obtained by the combined contributions from the repulsion and the quark Fermi repulsion. In both models of EoSs, the important roles of the di-quark exchange repulsions are demonstrated to reproduce reasonable values of and .

    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2408.03812 [pdf]
    PRC(2024)·6 citations
  6. 06

    [Submitted on 7 Aug 2024]

    Superfluid quantum criticality and the thermal evolution of neutron stars

    Hao-Fu Zhu🇨🇳 · Guo-Zhu Liu🇨🇳 · Jing-Rong Wang🇨🇳 · Xufen Wu🇨🇳

    The neutron star starts to cool down shortly after its birth by emitting neutrinos. As it becomes cold enough, the Cooper pairs of neutrons are formed, triggering a superfluid transition. Previous studies on neutron superfluidity focused on finite-temperature transitions, with little attention paid to the potentially important quantum critical phenomena associated with superfluidity. Here, we provide the first theoretical analysis of superfluid quantum criticality, concentrating on its impact on neutron star cooling. Extensive calculations found that superfluidity occurs within a finite range of neutron star density . The density serves as a nonthermal parameter for a superfluid quantum phase transition. In a broad quantum critical region, gapless neutrons are strongly coupled to the quantum critical fluctuations of the superfluid order parameter. We handle this coupling using both perturbation theory and renormalization group methods and find that it leads to non-Fermi liquid behavior, which yields a logarithmic correction to the neutron specific heat and also dramatically alters the neutrino emissivity. Quantum critical phenomena emerge much earlier than the onset of superfluidity and persist throughout almost the entire lifetime of a neutron star. At low temperatures, these phenomena coexist with superfluidity in the neutron star interior but occupy different layers. We incorporate superfluid quantum criticality into the theoretical description of neutron star cooling and show that it substantially prolongs the thermal relaxation time. By varying the strength of superfluid fluctuations and other quantities, we obtain an excellent fit to the observed cooling data of a number of neutron stars. Our results indicate an intriguing correlation between superfluid quantum criticality and the thermal evolution of neutron stars.

    Comments:
    32 pages, 6 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); Strongly Correlated Electrons (cond-mat.str-el); Superconductivity (cond-mat.supr-con)
    arXiv:
    2408.03931 [pdf]
    PRD(2025)·1 citation

Affiliations

first authorsco-authorsvia INSPIRE