Nuclear Theory·nucl-th

Tuesday·April 8, 2025

20 papers—9 primary·11 cross-listed

01
Determination of $S_{18}$ from $^{9}$ C breakup reaction within a four-body reaction model
Shoya Ogawa🇯🇵 · Tokuro Fukui🇯🇵 · Jagjit Singh🇬🇧 · Kazuyuki Ogata🇯🇵
The astrophysical factor $S_{18}$ for the $^{8}$ B( $p$ , $γ$ ) $^{9}$ C has indirectly been measured with the proton removal reactions from $^{9}$ C, elastic breakup of $^{9}$ C off a heavy target, and transfer reactions. Quite recently, the elastic breakup cross section data were reanalyzed with the continuum-discretized coupled channels method (CDCC) assuming a $p +^{8} B$ two-body model for $^{9}$ C and the $S_{18}$ was modified. It was not well justified, however, to treat $^{8}$ B as an inert nucleus given its proton separation energy is only 137~keV. We reexamine the elastic breakup of $^{9}$ C by the four-body CDCC with a $p + p +^{7} Be$ three-body model for $^{9}$ C and evaluate $S_{18}$ . To achieve this, we propose a method to disentangle the $p +^{8} B +^{208} Pb$ three-body channel in the four-body CDCC calculation, for the first time. We calculate the elastic breakup cross section of $^{9}$ C off a $^{208}$ Pb target at 65~MeV/nucleon. The obtained breakup cross sections are decomposed into the contributions of the $p +^{8} B +^{208} Pb$ and $p + p +^{7} Be +^{208} Pb$ channels by using the solution of the complex-scaled Lippmann--Schwinger equation. The breakup cross section to the $p +^{8} B +^{208} Pb$ channel reproduces well the shape of the experimental data in the low breakup energy region, which is important for determining $S_{18}$ . By fitting the theoretical result to the experimental data, the asymptotic normalization coefficient of $^{9}$ C for the $p +^{8} B$ configuration is determined and we obtain $S_{18} = 38.4 \pm 1.1$ eVb. This result is smaller than the previous value obtained with the three-body CDCC by about 45\%. Thus, our new results suggest the necessity of taking into account the fragile nature of $^{8}$ B in the $^{9}$ C breakup.
nucl-thPTEP(2026)·0 citations
02
Electromagnetic radii of light nuclei from variational Monte Carlo calculations
G. B. King🇺🇸 · G. Chambers-Wall🇺🇸 · A. Gnech🇺🇸 · S. Pastore🇺🇸 · M. Piarulli🇺🇸 · R. B. Wiringa🇺🇸
We present variational Monte Carlo calculations of charge and magnetic radii in $A \leq 10$ nuclei. The calculations are based on the Norfolk two- and three-nucleon interactions, and associated one- and two-nucleon electromagnetic charge and current operators derived up to next-to-next-to-next-to leading order in the chiral expansion. The charge and magnetic radii are extracted from the respective form factors. We find that the charge radii are within 5\% of the experimental values for the nuclei considered. For the magnetic radii, a comparison is available only with $^{3}$ H and $^{3}$ He electron scattering data that are affected by large error bars. We hope that our predictions foster an interest in precisely measuring magnetic radii of heavier systems.
nucl-thPRC(2025)·8 citations
03
Non-negligible influence of shape inheritance and staggering on {\alpha} decay
Ruixiong Li · Jingyu Xiao · Hongfei Zhang · Nana Ma
A series of findings in machine learning (ML) and decay theory are captured while exploring the role of deformation and preformation factors in {\alpha} decay. We provide a novel and practical paradigm for developing physics-driven machine learning in nuclear physics research by introducing known decay theory and statistical correlation analysis. Furthermore, this analysis verifies the Geiger-Nuttall law, and the relationship between the decay energy and {\alpha} formation amplitude, also releases a signal that nuclei with hexadecapole deformation are more likely to form {\alpha} clusters. In particular, we identify two novel phenomena, shape inheritance, in which the deformation properties are partially transmitted from parent to daughter nuclei; and half-life inversion due to shape staggering of adjacent even-even nuclei. This phenomenon occurs frequently in neutron-deficient nuclei near lead isotopes, which is consistent with shape coexistence in experiments. Surprisingly, it reappeared within the predicted half-life of the 119 and 120 isotope chains in the eighth period of the periodic table. The half-life considering the inversion effect is preferable for the study of new nuclides and shape coexistence in experiments.
nucl-th1 citation
04
Probability for synthesis of superheavy nuclei with Z=121
R. Zargini · S. A. Seyyedi
In this study the empirical method \cite{RN464} is used for calculating the evaporation residue (ER) cross section in the synthesis of superheavy nuclei (SHN). The superheavy nuclei examined in this work fall within the range $Z = 112 - 118$ . The theoretical calculations show good agreement with the experimental data. Furthermore, this model, along with an investigation of the optimal incident energy (OIE), is used to calculate the ER cross section for a hypothetical heavy system with $Z = 121$ . Five promising combinations are suggested for synthesis of SHN with $Z = 121$ : (1) $^{50} Ti +^{252} Es$ , with the maximum ER cross section $σ_{3 n} = 24.5 fb$ , at the optimal incident energy, $OIE = 230 MeV$ ; (2) $^{50} Ti +^{254} Es$ , with the maximum ER cross section $σ_{3 n} = 11.8 fb$ , at the optimal incident energy, $OIE = 229 MeV$ ; (3) $^{51} V +^{251} Cf$ , with the maximum ER cross section $σ_{3 n} = 1.2 fb$ , at the optimal incident energy, $OIE = 238 MeV$ ; (4) $^{51} V +^{249} Cf$ , with the maximum ER cross section $σ_{3 n} = 1.0 fb$ , at the optimal incident energy, $OIE = 238 MeV$ ; and (5) $^{54} Cr +^{247} Bk$ , with the maximum ER cross section $σ_{2 n} = 0.9 fb$ , at the optimal incident energy, $OIE = 243 MeV$ .
nucl-thPRC(2025)·0 citations
05
Harmonic Oscillator Representation of Scattering Theory in the Presence of Coulomb Potential
Ustin M Yanikov🇷🇺 · Vasily A Kulikov🇷🇺 · Andrey M Shirokov🇷🇺
Considering the problem of scattering of charged particles, we introduce a new approach of taking the Coulomb interaction into account within the HORSE formalism. Compared to the conventional HORSE approach for uncharged particles, we add a diagonal Coulomb term to} the three-term recurrent relation for expansion coefficients in the asymptotic region. The method simplifies calculations and demonstrates a good agreement with numerical solution.
nucl-thJ.Subatomic Part.Cosmol.(2025)·3 citations
06
Examination of the lattice QCD-motivated strong attractive $Ω N$ potentials in the $Ω^{-} n p$ system
I. Filikhin🇺🇸 · R. Ya. Kezerashvili🇺🇸 · B. Vlahovic🇺🇸
Within the framework of the Faddeev equations in configuration space, we examine the $Ω^{-} n p$ system, employing strongly attractive lattice HAL QCD and Yukawa-type meson exchange potentials for the $Ω N$ interaction. Our formalism incorporates the attractive Coulomb force between the $Ω^{-}$ and proton, treating the system as three non-identical particle pairs (the $A B C$ model). In this study, we assess the impact of the Coulomb interaction on the system and compare our results with recent $Ω N N$ ( $AA C$ model) calculations obtained using various approaches. The $A B C$ model yields low-energy characteristics for the $\Omega NN$ system that differ from previous calculations. The Coulomb potential has a marginal perturbative effect on the $AA C$ system, shifting the three-body binding energy by the Coulomb energy of the two-body $B C$ subsystem, but only slightly deviating the spatial configuration from isosceles triangle symmetry. These effects are primarily driven by the strong $\Omega N$ interaction. We demonstrate that the large binding energy of the $Ω^{-} n p$ system arises from the short-range behavior of the $Ω N$ potentials.
nucl-thhep-latPRD(2025)·4 citations
07
Identifying $α$ -cluster configurations in $^{20}$ Ne via ultracentral Ne+Ne Collisions
Pei Li🇨🇳 · Bo Zhou🇨🇳 · Guo-Liang Ma🇨🇳
The initial-state geometry in relativistic heavy-ion collisions provides a novel probe to nuclear cluster structure. For $^{20}$ Ne, a novel approach is proposed to distinguish between the cluster configurations (5 $α$ versus $α +^{16}$ O) in order to gain insight into nuclear structure transitions governed by many-body quantum correlations. Through analytical calculations with the microscopic Brink model and event-by-event simulations using the hydrodynamic framework, we establish the normalized symmetric cumulant NSC (3, 2) and the Pearson coefficient $ρ_{2} (v_{2}^{2}, δ [p_{T}])$ as quantitative discriminators to reveal enhanced cluster degrees of freedom in the ground state of $^{20}$ Ne. The ultracentral Ne+Ne collisions at the LHC can experimentally identify these two competing configurations via these flow correlation observables, opening a new paradigm for probing clustering in light nuclei.
nucl-thhep-phnucl-exPRL(2026)·15 citations
08
Fermi Operator Expansion for the Hartree-Fock-Bogoliubov Theory
Chengpeng Yu🇯🇵 · Takashi Nakatsukasa🇯🇵
A variety of phases in the inner crust of neutron stars are crucial for understanding the pulsar phenomena. However, the three-dimensional coordinate-space calculation of the phases is computationally demanding. We aim to generalize the Fermi operator expansion (FOE) method that is effective for finite-temperature coordinate-space simulation, from the Hartree-Fock theory to Hartree-Fock-Bogoliubov (HFB) theory including the pairing effects. Furthermore, the periodic structure with free neutrons in the inner crust requires us to treat the system with the band theory. We give a concise proof that the generalized density matrix in the HFB theory can be obtained with the FOE. The Chebyshev polynomial expansion is used for calculations of the HFB band theory. Using a model for a slab phase of the inner crust, the FOE method produces results in good agreement with those based on the diagonalization of the HFB Hamiltonian. The FOE method for the HFB band theory is a powerful tool for studying the nontrivial exotic structures in neutron stars. The FOE method is suitable for parallelization and further acceleration is possible with nearsightedness.
nucl-thPRC(2025)·0 citations
09
The role of the screening potential in the deuteron-deuteron thermonuclear reaction rates
Faisal Etminan🇮🇷
The deuteron-deuteron (D-D) thermonuclear reaction rates in metallic environments (considering the electron screening effects) is calculated using the S-factor functions which were obtained by fitting to low-energy data on D-D reactions. For this purpose, a fitted S-factor model based on the NACRE compilation is employed. This limited the energy range of Big Bang nucleosynthesis (BBN) for the $^{2} H (d, p)^{3} H$ and $^{2} H (d, n)^{3} He$ reactions. The corresponding Maxwellian-averaged thermonuclear reaction rates of relevance in astrophysical plasmas at temperatures in the range from $1 0^{6}$ K to $1 0^{10} (or 1.3 \times 1 0^{8})$ K are provided in tabular formats. In these evaluations, the screening energy ( $U_{e}$ ) is assumed to be $100, 400, 750, 1000$ eV and $1250$ eV. This series of values has been selected based on theoretical and experimental studies conducted so far. % Eventually, our numerical analysis suggests that the ratio of the reaction rate with the screening potential to the reaction rate without the screening potential, can be described by the term $exp (4.70 + 6.50 U_{e} / T_{9})$ for both $^{2} H (d, p)^{3} H$ and $^{2} H (d, n)^{3} He$ reactions. This series of values has been selected based on theoretical and experimental studies conducted so far.
nucl-thnucl-exNPA(2026)·0 citations

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first authorsco-authorsvia INSPIRE