Nuclear Theory·nucl-th

Thursday·September 5, 2024

8 papers—4 primary·4 cross-listed

01
Structure of odd-mass Ne, Na, and Mg nuclei
Z. H. Sun · T. R. Djärv · G. Hagen · G. R. Jansen · T. Papenbrock
The island of inversion is a region of neutron-rich nuclei that are deformed in their ground states. In this region, less is known about the energy levels of odd-mass nuclei, how they evolve with increasing neutron numbers, and how they can be organized into rotational bands. We perform {\it ab initio} coupled-cluster calculations of spectra in odd-mass Ne, Na, and Mg nuclei based on an interaction of chiral effective field theory. Our results confirm some tentative spin and parity assignments, predict the structure of nuclei near the neutron dripline, and inform us about rotational bands in this region of the nuclear table.
nucl-thPRC(2025)·12 citations
02
Deformation probes for light nuclei in their collisions at relativistic energies
Hai-Cheng Wang🇨🇳 · Song-Jie Li🇨🇳 · Lu-Meng Liu🇨🇳 · Jun Xu🇨🇳 · Zhong-Zhou Ren🇨🇳
We have investigated the performance of anisotropic flows $⟨ v_{n}^{2} ⟩$ , transverse momentum fluctuations $⟨ δ p_{T}^{2} ⟩$ , and their correlations $⟨ v_{n}^{2} δ p_{T} ⟩$ in central collisions at relativistic energies as probes of deformation parameters $β_{n}$ of colliding nuclei, if these nuclei are light nuclei with large $β_{n}$ and different configurations of $α$ clusters. The effects from higher-order $β_{n}$ terms are illustrated by derived relations based on the overlap of two nuclei with uniform density distributions and by dynamic simulations of collisions of heavy nuclei whose density distributions are of a deformed Woods-Saxon (WS) form. While the linear relations between $β_{n}^{2}$ , $⟨ v_{n}^{2} ⟩$ , and $⟨ δ p_{T}^{2} ⟩$ and that between $β_{n}^{3}$ and $⟨ v_{n}^{2} δ p_{T} ⟩$ can be violated for extremely large $β_{n}$ , they are mostly valid for realistic values of $β_{n}$ , as long as the density distribution of colliding nuclei can be described by a deformed WS form. However, these linear relations are generally not valid with more realistic density distributions of light nuclei with $α$ clusters, and the amount of deviation depends on the detailed $α$ -cluster configurations. Care must be taken when one tries to extract the deformation of light nuclei, and specific probes for $α$ -cluster structures in these nuclei are very much needed.
nucl-thhep-exnucl-exPRC(2024)·14 citations
03
Calculation of The Abundance of $^{187}$ Re- $^{187}$ Os Nuclear Clock Nuclides in S-process and Sensitivity Analysis of Maxwellian-Averaged Neutron Capture Cross Sections
Xinyu Dong · Yixuan Qiu · Kaisu Wu
In this paper, the network equations calculation of $^{187}$ Re- $^{187}$ Os clock-related nuclide abundance in s-process is studied, and the sensitivities of Maxwellian-Averaged neutron capture cross sections for each nuclide are analyzed in detail. Firstly, basing nuclear physical parameters, we give the branching s-process reaction network from $^{184}$ W to $^{190}$ Os, and establish the corresponding network equations. Using a single path s-process approximation, we obtain an analytical expression of the seed nuclide $^{183}$ W abundance of our branching network. Because of the stiffness of the system of network equations, we use the semi-implicit Runge-Kutta method to give the numerical solution of the network equations, and thus obtain the abundance of each nuclide related to the $^{187}$ Re- $^{187}$ Os nuclear clock in the s-process. Finally, with the numerical solution, the sensitivity analysis of the Maxwellian-Averaged neutron capture cross sections of the nuclear reaction involved in the $^{187}$ Re- $^{187}$ Os nuclear clock network equations is carried out. Therefore, we find that in s-process, the neutron capture reaction $^{184}$ W + n $\to$ $^{185}$ W has the greatest influence on the $^{187}$ Re- $^{187}$ Os nuclear clock reaction network, and the neutron capture reaction $^{186}$ W + n $\to$ $^{187}$ W has the greatest effect on the particular nuclides $^{187}$ Re and $^{187}$ Os. So the measurements of these two Maxwellian-Averaged neutron capture cross sections deserve the attention of experimental nuclear physicists.
nucl-thEPJA(2025)·0 citations
04
Fission of $^{180}$ Hg and $^{264}$ Fm: a comparative study
Bernard Remi🇫🇷 · Simenel Cedric🇦🇺 · Blanchon Guillaume🇫🇷 · Lau Ngee-Wein🇦🇺 · McGlynn Patrick🇦🇺
$^{180}$ Hg is experimentally found to fission asymmetrically. This result was not expected as a naive fragment shell effects study would support the symmetric mode to be the most probable. In the present study we investigate both symmetric and asymmetric $^{180}$ Hg fission modes at the mean field level using various multipole moment constraints. Potential energy surfaces are analysed in terms of shell effects that shape their topographies and connections to fragment shell effects are made. The non-occurrence of low energy symmetric fission is interpreted in terms of $^{90}$ Zr fragment properties. Throughout this study a comparison with $^{264}$ Fm and its symmetric doubly magic $^{132}$ Sn fission fragments is done.
nucl-thEPJA(2024)·6 citations
05
Decoding Dark Matter Admixed Neutron Stars: From Static Structure to Rotational Deformation
Pinku Routaray🇮🇳 · Abirbhav Chakrawarty🇮🇳 · N. K. Patra🇨🇳 · Bharat Kumar🇮🇳
In this study, we investigate the impacts of dark matter (DM) on the properties of both static and rotating neutron stars utilizing a self-interacting DM model, motivated by the neutron decay anomaly. DM-admixed NSs are modeled by assuming chemical equilibrium between ordinary matter and the dark sector, treating a single-fluid Tolman-Oppenheimer-Volkoff (TOV) framework. By treating the DM interaction strength ( $G$ ) as a free parameter, we explore its influence on NS properties, considering a broad range of equations of state (EoSs). Using the mass-radius constraints from NICER pulsar measurements, we constrain the DM interaction strength for each EoS via a likelihood analysis. Extending this model to rotating NSs, we analyze how centrifugal forces associated with increasing angular velocity ( $Ω$ ) enhance both mass and radius, causing deformation. We assess the impact of DM on rotational deformation by calculating the eccentricity, highlighting the interplay between DM and rotational forces. Since both DM and rotation simultaneously influence NS properties, we compute the relative changes in mass and radius across varying $G$ and $Ω$ values to quantify their combined effects.
↳ astro-ph.HEgr-qchep-phnucl-thPhys.Dark Univ.(2025)·10 citations
06
Origins and impacts of dynamical diquark correlations -- A continuum Schwinger functional approach --
Jorge Segovia🇪🇸
This conference proceedings contribution emphasizes the emergent hadron mass paradigm, which accounts for the majority of the visible mass in the universe, beyond the Higgs boson mechanism. The study delves into the Landau gauge gluon propagator and the dynamical generation of gluon mass, as well as the dressed-quark propagator and dynamical chiral symmetry breaking. It also tackles the baryon bound state problem through the Poincaré-covariant Faddeev equation, analyzing the composition and masses of octet and decuplet baryons. The document concludes with a discussion on the electromagnetic form factors of the nucleon and its first radial excitation, providing insights into the quark-diquark structure within baryons.
↳ hep-phhep-exhep-latnucl-ex+1PoS(2025)·0 citations
07
Anisotropic pressure effect on central EOS of PSR J0740+6620 in the light of dimensionless TOV equation
Zhihao Yang · Dehua Wen
It is generally agreed upon that the pressure inside a neutron star is isotropic. However, a strong magnetic field or superfluidity suggests that the pressure anisotropy may be a more realistic model. We derived the dimensionless TOV equation for anisotropic neutron stars based on two popular models, namely the BL model and the H model, to investigate the effect of anisotropy. Similar to the isotropic case, the maximum mass $M_{ma x}$ and its corresponding radius $R_{M ma x}$ can also be expressed linearly by a combination of radial central pressure $p_{r c}$ and central energy density $ε_{c}$ , which is insensitive to the equation of state (EOS). We also found that the obtained central EOS would change with different values of $λ_{B L}$ ( $λ_{H}$ ), which controls the magnitude of the difference between the transverse pressure and the radial pressure. Combining with observational data of PSR J0740+6620 and comparing to the extracted EOS based on isotropic neutron star, it is shown that in the BL model, for $λ_{B L}$ = 0.4, the extracted central energy density $ε_{c}$ changed from 546 -- 1056 MeV/fm $^{3}$ to 510 -- 1005 MeV/fm $^{3}$ , and the extracted radial central pressure $p_{r c}$ changed from 87 -- 310 MeV/fm $^{3}$ to 76 -- 271 MeV/fm $^{3}$ . For $λ_{B L}$ = 2, the extracted $ε_{c}$ and $p_{r c}$ changed to 412 -- 822 MeV/fm $^{3}$ and 50 -- 165 MeV/fm $^{3}$ , respectively. In the H model, for $λ_{H}$ = 0.4, the extracted $ε_{c}$ changed to 626 -- 1164 MeV/fm $^{3}$ , and the extracted $p_{r c}$ changed to 104 -- 409 MeV/fm $^{3}$ . For $λ_{H}$ = 2, the extracted $ε_{c}$ decreased to 894 -- 995 MeV/fm $^{3}$ , and the extracted $p_{r c}$ changed to 220 -- 301 MeV/fm $^{3}$ .
↳ astro-ph.HEastro-ph.SRnucl-thCPC(2024)·2 citations
08
Configurational entropy and stability conditions of fermion and boson stars
P.S. Koliogiannis🇭🇷 · M. Vikiaris🇬🇷 · C. Panos🇬🇷 · V. Petousis🇨🇿 · M. Veselsky🇨🇿 · Ch.C. Moustakidis🇬🇷
In a remarkable study by M. Gleiser and N. Jiang [Phys. Rev. D {\bf 92}, 044046, 2015], the authors demonstrated that the stability regions of neutron stars, within the framework of the simple Fermi gas model, and self-gravitating configurations of complex scalar field (boson stars) with various self couplings, obtained through traditional perturbation methods, correlate with critical points of the configurational entropy with an accuracy of a few percent. Recently, P. Koliogiannis \textit{et al.} [Phys. Rev. D {\bf 107}, 044069 2023] found that while the minimization of the configurational entropy generally anticipates qualitatively the stability point for neutron stars and quark stars, this approach lacks universal validity. In this work, we aim to further elucidate this issue by seeking to reconcile these seemingly contradictory findings. Specifically, we calculate the configurational entropy of bosonic and fermionic systems, described by interacting Fermi and boson gases, respectively, that form compact objects stabilized by gravity. We investigate whether the minimization of configurational entropy coincides with the stability point of the corresponding compact objects. Our results indicate a strong correlation between the stability points predicted by configurational entropy and those obtained through traditional methods, with the accuracy of this correlation showing a slight dependence on the interaction strength. Consequently, the stability of compact objects, composed of components obeying Fermi or boson statistics, can alternatively be assessed using the concept of configurational entropy.
↳ gr-qcastro-ph.HEnucl-thphysics.comp-phPRD(2024)·4 citations

Affiliations

first authorsco-authorsvia INSPIRE