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Nuclear Theory·nucl-th

Wednesday·January 15, 2025

11 papers—5 primary·6 cross-listed

All11Primary5Cross-lists6
  1. 01

    Proton halo structures and 22Al

    Panagiota Papakonstantinou · Myeonghwan Mun · Cong Pan · Kaiyuan Zhang

    Inspired by the recent debate as to whether the proton drip-line nucleus 22Al demonstrates a halo structure in its ground state and in order to assess such a possibility, we have analyzed theoretical results obtained within the relativistic density functional theory in 22Al and in a number of neighboring nuclei especially along isotopic, isotonic, and isobaric chains. The theory includes self-consistently the effects of pairing, deformation and the continuum. We employ two different functional parameterizations, PC-F1 and PC-PK1. Although the valence proton of the 22Al nucleus is found very loosely bound, in concordance with experimental data, its spatial distribution is found to hardly penetrate the potential barrier. Its wave function is found to consist predominately of l=2 components, for which halo formation is disfavored. Comparisons with results for isobars reveal a somewhat more extended density distribution than that of the stable or neutron-rich counterparts, but comparisons along isotopic, isotonic, and isobaric chains reveal no discontinuities in size evolution, which, if present, might have signaled exotic structures.

    nucl-thnucl-exPRC(2025)·14 citations
  2. 02

    Halo Structures in p-Shell Hypernuclei with Natural Orbitals

    Marco Knöll · Robert Roth

    We extend the concept of natural orbitals as an optimized single-particle basis for ab initio nuclear many-body calculations to hypernuclei and show that their superior properties, in particular accelerated convergence and independence of the underlying harmonic-oscillator frequency, can be directly transferred to the hypernuclear regime as demonstrated in no-core shell model calculations for selected p-shell hypernuclei. Moreover, the radial single-particle wavefunctions associated with the natural-orbital basis yield important structural information with respect to the different particle species allowing us to identify a hyperon halo in {\Lambda}He5. We further explore nucleonic and hyperonic halo structures in A=6 and A=7 singly-strange hypernuclei based on one-body densities and point-particle radii obtained from no-core shell model calculations with realistic interactions from chiral effective field theory.

    nucl-thPLB(2026)·5 citations
  3. 03

    Pressure and chemical potentials in the inner crust of a cold neutron star within Hartree-Fock and extended Thomas-Fermi methods

    Nicolas Chamel · Nikolai N. Shchechilin · Andrey I. Chugunov

    Self-consistent mean-field methods with Skyrme-type effective interactions and semiclassical approximations, such as the Thomas-Fermi approach and its extensions are particularly well-suited for describing in a thermodynamically consistent way the various phases of the dense matter present in the interior of neutron stars. These methods have been applied to predict the composition of the different regions, including the inner crust constituted by nuclear clusters coexisting with free neutrons and electrons. Because of the computational cost, the energy is typically calculated for a few selected average baryon number densities, and the results are interpolated to obtain the pressure numerically. However, this may introduce systematic errors in the calculations of the global structure of a neutron star and its dynamical evolution. In this paper, we show how the full equation of state can be consistently calculated within the same framework by deriving exact formulas for the chemical potentials and for the pressure that can be easily implemented in existing computer codes. These formulas are applicable to both catalyzed and accreted crusts. We discuss in each case the suitable conditions to impose to determine the composition. Numerical examples are also presented and discussed. Results from refined calculations of the BSk24 equation of state for the inner crust of nonaccreted neutron stars and the corresponding adiabatic index are provided.

    nucl-thastro-ph.HEPRC(2025)·4 citations
  4. 04

    Energy dependence of transverse momentum fluctuations in Au+Au collisions from a multiphase transport model

    Liuyao Zhang🇨🇳 · Jinhui Chen🇨🇳 · Chunjian Zhang🇨🇳

    Event-by-event mean transverse momentum fluctuations () serve as a sensitive probe of initial state overlap geometry and energy density fluctuations in relativistic heavy-ion collisions. We present a systematic investigation of fluctuations in \auau collisions at 3.0-19.6 GeV, examining their centrality and energy dependence with the framework of an improved multiphase transport (AMPT) model. The centrality dependence of the cumulants up to fourth order deviates significantly from simple powering-law scaling. Scaled cumulants are performed, with variances aligning well with the trends observed in the experimental data. Employing a two-subevent method, short-range correlations are slightly suppressed compared to the standard approach. Furthermore, baryons exhibit more pronounced fluctuations than mesons, potentially attributable to the effect of radial flow. These results provide referenced insights into the role of initial state fluctuations across different energies in heavy-ion collisions.

    nucl-thnucl-exPRC(2025)·15 citations
  5. 05

    Two- versus three-body approach to femtoscopic hadron-deuteron correlations

    Stanislaw Mrowczynski🇵🇱

    The three-body approach to hadron-deuteron correlations is shown to turn into a two-body approach if the three-particle hadron-deuteron wave function factorizes into the deuteron wave-function and the wave function of a hadron motion relative to the deuteron. Then, the hadron-deuteron correlation function is as in the two-body approach only the source radius somewhat changes. For this reason, as we argue, the two-body approach works well for kaon-deuteron correlations but it fails for proton-deuteron ones in case of small sources. Applying the three-body approach generalized to the case where the radius of the hadron source is different from the nucleon source radius, we derive the source radius formula which used in the two-body approach gives the correlation function as in the `factorized' three-body one. The formula is discussed in the context of existing and future experimental data.

    nucl-thhep-phnucl-exPLB(2025)·6 citations

Affiliations

first authorsco-authorsvia INSPIRE