PaperPanorama
FAQ

Nuclear Theory·nucl-th

Tuesday·September 13, 2022

14 papers—7 primary·7 cross-listed

All14Primary7Cross-lists7
  1. 01

    [Submitted on 10 Sept 2022]

    Microscopic aspects of -softness in atomic nuclei

    Nazira Nazir · S. Jehangir · S.P. Rouoof · G.H. Bhat · J. A. Sheikh · N. Rather · S.Frauendorf

    The microscopic origin of the -softness (fluctuations in the triaxiality parameter of the nuclear shape) observed in atomic nuclei is studied in the framework of the triaxial projected shell model approach, which is based on the deformed mean-field picture with multi-quasiparticle configuration space. It is demonstrated that the coupling to quasiparticle excitations drives the system from a -rigid to a -soft pattern. As an illustrative example for a -soft nucleus, a detailed study has been performed for the Ru nucleus. The experimental energies and a large sample of measured matrix elements available for this nucleus are reproduced quite accurately. The shape invariant analysis of the calculated matrix elements elucidates the -soft nature of Ru.

    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    2209.04718 [pdf]
    15 citations
  2. 02

    [Submitted on 11 Sept 2022]

    Three-nucleon system: Irreducible and reducible contributions of the three-nucleon force

    A. Deltuva · P.U. Sauer

    The three-nucleon bound and scattering equations are solved in momentum space for a coupled-channel Hamiltonian. The Hamiltonian couples the purely nucleonic sector of Hilbert space with a sector in which one nucleon is excited to a isobar. The interaction consists of irreducible two-baryon and irreducible three-baryon potentials. The calculation keeps only the purely nucleonic one among the irreducible three-baryon potentials. The coupled-channel two-baryon potential yields additional reducible contributions to the three-nucleon force. The Coulomb interaction between the two protons is included using the method of screening and renormalization. Three-nucleon force effects on the bound-state energies and on observables of elastic nucleon-deuteron scattering and breakup are studied.

    Comments:
    10 pages, 11 figures
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2209.04855 [pdf]
    PRC(2015)·11 citations
  3. 03

    [Submitted on 11 Sept 2022]

    Measuring the speed of sound using cumulants of baryon number

    Agnieszka Sorensen🇺🇸 · Dmytro Oliinychenko🇺🇸 · Larry McLerran🇺🇸 · Volker Koch🇺🇸

    We show that the values of the first three cumulants of the baryon number distribution can be used to calculate the isothermal speed of sound and its logarithmic derivative with respect to the baryon number density. We discuss applications of this result to heavy-ion collision experiments and address possible challenges, including effects due to baryon number conservation, differences between proton and baryon cumulants, and the influence of finite number statistics on fluctuation observables in both experiment and hadronic transport simulations. In particular, we investigate the relation between quantities calculated in infinite, continuous matter and observables obtained in simulations using a finite number of particles.

    Comments:
    6 pages, 1 figure, presented at the XXIXth International Conference on Ultra-relativistic Nucleus-Nucleus Collisions (Quark Matter 2022)
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2209.04957 [pdf]
    Acta Phys.Polon.Supp.(2023)·5 citations
  4. 04

    [Submitted on 12 Sept 2022]

    Nucleonic metamodelling in light of multimessenger, PREX-II and CREX data

    Chiranjib Mondal🇫🇷 · Francesca Gulminelli🇫🇷

    The need of reconciling our understanding of the behavior of hadronic matter across a wide range of densities, especially at the time when data from multimessenger observations and novel experimental facilities are flooding in, has provided new challenges to the nuclear models. Particularly, the density dependence of the isovector channel of the nuclear energy functionals seems hard to pin down if experiments like PREX-II (or PREX) and CREX are required to be taken on the same footing. We put to test this anomaly in a semi-agnostic modelling technique, by performing a full Bayesian analysis of static properties of neutron stars, together with global properties of nuclei as binding energy, charge radii and neutron skin calculated at the semi-classical level. Our results show that the interplay between bulk and surface properties, and the importance of high order empirical parameters that effectively decouple the subsaturation and the supersaturation density regime, might partially explain the tension between the different measurements and observations. If the surface behaviors, however, are decoupled from the bulk properties, we found a rather harmonious situation among experimental and observational data.

    Comments:
    13 pages, 12 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Experiment (nucl-ex)
    arXiv:
    2209.05177 [pdf]
    PRC(2023)·54 citations
  5. 05

    [Submitted on 12 Sept 2022]

    Squeezed spectra and elliptic flow of bosons and anti-bosons with in-medium mass splitting

    Yong Zhang🇨🇳 · Shi-Yao Wang🇨🇳 · Peng Ru🇨🇳 · Wei-Hua Wu🇨🇳

    We study the impact of the in-medium mass splitting between bosons and anti-bosons on their spectra and elliptic flow. The in-medium mass splitting may cause a separation in the transverse momentum spectra, as well as a division in the elliptic flow between bosons and anti-bosons. The magnitude of this effect becomes greater as the in-medium mass splitting increases. With the increasing rapidity, the splitting effect of the spectra increases and the splitting effect of the elliptic flow decreases. These phenomena may provide a way to differentiate whether the influences on boson and anti-boson in the medium are consistent.

    Comments:
    12 pages, 8 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph)
    arXiv:
    2209.05262 [pdf]
    IJMPE(2023)·0 citations
  6. 06

    [Submitted on 12 Sept 2022]

    Enhanced dilepton emission from a phase transition in dense matter

    O. Savchuk🇩🇪 · A. Motornenko🇩🇪 · J. Steinheimer🇩🇪 · V. Vovchenko🇩🇪 · M. Bleicher🇩🇪 · M. Gorenstein🇺🇦 · T. Galatyuk🇩🇪

    It is demonstrated that the presence of a phase transition in heavy ion collisions, at beam energies that probe dense QCD matter, leads to a significant enhancement of the dilepton yield per produced pion due to the extended emission time. In addition, the temperature of low mass dileptons shows a modest decrease due to the mixed phase. The emission of dileptons in the SIS18-SIS100 beam energies range is studied by augmenting the UrQMD transport model with a realistic density dependent equation of state, as well as two different phase transitions. This is achieved by extending the molecular dynamics interaction part of the UrQMD model to a density dependent interaction potential with a high density minimum leading to a phase transition and metastable coexisting high density states. Together with a high precision measurement these simulations will be able to constrain the existence of a phase transition in QCD up to densities of several times nuclear saturation density.

    Comments:
    8 pages, 5 figures
    Subjects:
    Nuclear Theory (nucl-th); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
    arXiv:
    2209.05267 [pdf]
    J.Phys.G(2023)·29 citations
  7. 07

    [Submitted on 12 Sept 2022]

    Effects of finite sizes of atomic nuclei on shear modulus and torsional oscillations in neutron stars

    Hajime Sotani · Hajime Togashi · Masatoshi Takano

    The shear modulus of neutron star matter is one of the important properties for determining torsional oscillations in neutron stars. We take into account the effects of finite sizes of spherical nuclei on the shear modulus and examine the frequencies of crustal torsional oscillations. The shear modulus decreases owing to the finite-size effect, which in turn decreases the frequencies of torsional oscillations. In particular, the finite-size effect becomes more crucial for oscillations with a larger azimuthal quantum number and for neutron star models with a weaker density dependence of nuclear symmetry energy. In practice, when one identifies the quasi-periodic oscillations from a neutron star, where the magnetic effect is negligible, with crustal torsional oscillations, the finite-size effect can be more significant at frequencies higher than Hz.

    Comments:
    Accepted for publication in MNRAS
    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
    arXiv:
    2209.05416 [pdf]
    MNRAS(2022)·6 citations

Affiliations

first authorsco-authorsvia INSPIRE