Nuclear Theory·nucl-th

Tuesday·May 14, 2024

20 papers—7 primary·13 cross-listed

01
Reconstruction of Bremsstrahlung $γ$ -rays Spectrum in Heavy Ion Reactions with Richardson-Lucy Algorithm
JunHuai Xu · Yuhao Qin · Zhi Qin · Dawei Si · Boyuan Zhang · Yijie Wang · Qinglin Niu · Chang Xu · Zhigang Xiao
The high momentum tail (HMT) in the momentum distribution of nucleons above the Fermi surface has been regarded as an evidence of short-range correlations (SRCs) in atomic nuclei. It has been showcased recently that the $n p$ Bremsstrahlung radiation in heavy ion reactions can be used to extract HMT information. The Richardson-Lucy (RL) algorithm is introduced to the reconstruction of the original Bremsstrahlung $γ$ -ray energy spectrum from experimental measurements. By solving the inverse problem of the detector response to the $γ$ -rays, the original energy spectrum of the Bremsstrahlung $γ$ in 25 MeV/u $^{86}$ Kr + $^{124}$ Sn has been reconstructed and compared to the isospin- and momentum-dependent Boltzmann-Uehling-Uhlenbeck (IBUU) simulations. The analysis based on hypothesis test suggests the existence of the HMT of nucleons in nuclei, in accordance with the previous conclusions. With its effectiveness being demonstrated, it is feasible to apply the RL algorithm in future experiments of measuring the Bremsstrahlung $γ$ -rays in heavy ion reactions.
nucl-thnucl-exPLB(2024)·10 citations
02
Nuclear matter and finite nuclei: recent studies based on Parity Doublet Model
Yuk-Kei Kong🇯🇵 · Youngman Kim🇰🇷 · Masayasu Harada🇯🇵
In this review, we summarize recent studies on nuclear matter and finite nuclei based on parity doublet models. We first construct a parity doublet model (PDM), which includes the chiral invariant mass $m_{0}$ of nucleons together with the mass generated by the spontaneous chiral symmetry breaking. We then study the density dependence of the symmetry energy in the PDM, which shows that the symmetry energy is larger for smaller chiral invariant mass. Then, we investigate some finite nuclei by applying the Relativistic Continuum Hartree-Bogoliubov (RCHB) theory to the PDM. We present the root-mean-square deviation (RMSD) of the binding energies and charge radii, and show that $m_{0}$ = 700 MeV is preferred by the nuclear properties. Finally, we modify the PDM by adding the iso-vector scalar meson $a_{0} (980)$ and show that the inclusion of the $a_{0} (980)$ enlarges the symmetry energy of the infinite nuclear matter.
nucl-thhep-phSymmetry(2024)·6 citations
03
The Quenched $g_{A}$ Puzzle in Nuclei & Nuclear Matter and "Pseudo-Conformality" in QCD
Mannque Rho
The long-standing puzzle of the quenched $g_{A}$ in nuclei is shown to have an extremely simple resolution in a renormalization-group (RG) treatment of a hidden local symmetric (HLS) and scale-symmetric (HSS) chiral Lagrangian. It is shown that the Landau-Migdal fixed-point approximation in nuclear matter (or $V_{l o w k}$ in finite nuclei) in RG approach to strong correlations of fermionic hadrons on the Fermi surface {\it exactly} reproduces the superallowed Gamow-Teller transitions in the ``Extreme Single-Particle (shell-)Model (ESPM)" in doubly-magic closed shell nuclei. One arrives at the quenching factor $q \approx 0.78$ giving the quenched $g_{A}^{eff} \approx 1$ . This resolution exposes scale-chiral symmetry, hidden in QCD in the vacuum, emerging in nuclear matter from low density to high compact-star density. It has important implications on ``first principles" approaches to nuclear physics, such as the role of multi-body exchange currents in weak axial-current matrix elements in nuclei and in neutrinoless double $β$ decays for going Beyond the Standard Model. This resolution could put in serious doubt the most recent improved measurement of the superallowed Gamow-Teller transition in the doubly-magic closed shell nucleus $^{100}$ Sn which if confirmed would require a ``{\it fundamental quenching}" $q_{ss b} \sim 1/2$ .
nucl-thhep-phSymmetry(2024)·2 citations
04
Shell structure and shape transition in odd- $Z$ superheavy nuclei with proton numbers $Z = 117, 119$ : insights from deformed relativistic Hartree-Bogoliubov in continuum
Y. X. Zhang · B. R. Liu · K. Y. Zhang · J. M. Yao
We present a systematic study on the structural properties of odd- $Z$ superheavy nuclei with proton numbers $Z = 117, 119$ , and neutron numbers $N$ increasing from $N = 170$ to the neutron dripline within the framework of axially deformed relativistic Hartree-Bogoliubov theory in continuum (DRHBc). The results are compared with those of even-even superheavy nuclei with proton numbers $Z = 118$ and $120$ . We analyze various bulk properties of their ground states, including binding energies, quadrupole deformations, root-mean-square radii, nucleon separation energies, and $α$ -decay energies. The coexistence of competing prolate and oblate or spherical shapes leads to abrupt changes in both quadrupole deformations and charge radii as functions of neutron numbers. Compared to even-even nuclei, the odd-mass ones exhibit a more complicated transition picture, in which the quantum numbers of $K^{π}$ of the lowest-energy configuration may change with deformation. This may result in the change of angular momentum in the ground-state to ground-state $α$ -decay and thus quench the decay rate in odd-mass nuclei. Moreover, our results demonstrate a pronounced proton shell gap at $Z = 120$ , instead of $Z = 114$ , which is consistent with the predictions of most covariant density functional theories. Moreover, large neutron shell gaps are found at $N = 172$ and $N = 258$ in the four isotopic chains, as well as at $N = 184$ in the light two isotopic chains with $Z = 117$ and $Z = 118$ , attributed to the nearly-degenerate $3 d$ and $4 p$ spin-orbit doublet states due to the presence of bubble structure.
nucl-thnucl-exPRC(2024)·13 citations
05
The 25th anniversary for nuclear chirality
J. Meng · Y. P. Wang
The brief history for the prediction of the nuclear chirality is provided. The theoretical and experimental investigations of the nuclear chirality are reviewed, including the verification of chiral doublet bands, the chiral conundrum and its resolution, and the prediction and observation of the multiple chiral doublets (M $χ$ D). Some recent theoretical progresses are highlighted, including the chiral collective Hamiltonian, the A-plot and the K-plot, the nuclear chirality-parity (ChP) violation, the chiral rotation induced by the pairing correlations, as well as the chiral dynamics. The possibly emerging area, challenges that lie ahead, and opportunities for progress in the context of the nuclear chirality are discussed.
nucl-thnucl-ex1 citation
06
A study of nuclear structure of light nuclei at the Electron-Ion Collider
Niseem Magdy · Mariam Hegazy · Aliaa Rafaat · Wenliang Li · Abhay Deshpande · A. M. H. Abdelhady · A. Y. Ellithi · Roy A. Lacey · Zhoudunming Tu
Understanding the substructure of atomic nuclei, particularly the clustering of nucleons inside them, is essential for comprehending nuclear dynamics. Various cluster configurations can emerge depending on excitation energy, the number and types of core clusters, and the presence of excess neutrons. Despite the prevalence of tightly bound cluster formations in low-lying states, understanding the correlation between clusters and their formation mechanisms remains incomplete. This exploring study investigates nuclear clustering at the Electron-Ion Collider (EIC) using simulations based on the modified BeAGLE model. By simulating collisions involving $e$ + $^{9}$ Be, $e$ + $^{12}$ C, and $e$ + $^{16}$ O nuclei, we find that the average energy of particles $⟨ E ⟩$ and the system size ratios of particles at forward rapidity exhibit sensitivity to alpha clustering and its various configurations. These findings offer valuable insights into the dynamics of nuclear clustering and its implications for future studies at the EIC.
nucl-thhep-phnucl-exEPJA(2024)·14 citations
07
Study of the direct $^{16} O (p, γ)^{17} F$ astrophysical capture reaction within a potential model approach
E.M. Tursunov · S.A. Turakulov
A potential model is applied for the analysis of the astrophysical direct nuclear capture process $^{16}$ O(p, $γ)^{17}$ F. The phase-equivalent potentials of the Woods-Saxon form for the p $-^{16}$ O interaction are examined which reproduce the binding energies and the empirical values of ANC for the $^{17}$ F(5/2 $^{+}$ ) ground and $^{17}$ F(1/2 $^{+}$ ) ( $E^{*}$ =0.495 MeV) excited bound states from different sources. The best description of the experimental data for the astrophysical $S$ factor is obtained within the potential model which yields the ANC values of 1.043 fm $^{- 1/2}$ and 75.484 fm $^{- 1/2}$ for the $^{17}$ F( $5/ 2^{+}$ ) ground and $^{17}$ F( $1/ 2^{+}$ ) excited bound states, respectively. The zero-energy astrophysical factor $S (0) = 9.321$ KeV b is obtained by using the asymptotic expansion method of D. Baye. The calculated reaction rates within the region up to 10 $^{10}$ K are in good agreement with those from the R-matrix approach and the Bayesian model in both absolute values and temperature dependence.
nucl-thNPA(2024)·2 citations

Affiliations

first authorsco-authorsvia INSPIRE

Reconstruction of Bremsstrahlung γ-rays Spectrum in Heavy Ion Reactions with Richardson-Lucy Algorithm

Nuclear matter and finite nuclei: recent studies based on Parity Doublet Model

The Quenched gA​ Puzzle in Nuclei & Nuclear Matter and "Pseudo-Conformality" in QCD

Shell structure and shape transition in odd-Z superheavy nuclei with proton numbers Z=117,119: insights from deformed relativistic Hartree-Bogoliubov in continuum

The 25th anniversary for nuclear chirality

A study of nuclear structure of light nuclei at the Electron-Ion Collider

Study of the direct 16O(p,γ)17F astrophysical capture reaction within a potential model approach

Affiliations

Reconstruction of Bremsstrahlung $γ$ -rays Spectrum in Heavy Ion Reactions with Richardson-Lucy Algorithm

The Quenched $g_{A}$ Puzzle in Nuclei & Nuclear Matter and "Pseudo-Conformality" in QCD

Shell structure and shape transition in odd- $Z$ superheavy nuclei with proton numbers $Z = 117, 119$ : insights from deformed relativistic Hartree-Bogoliubov in continuum

Study of the direct $^{16} O (p, γ)^{17} F$ astrophysical capture reaction within a potential model approach