Nuclear Theory·nucl-th

Tuesday·August 12, 2025

17 papers—9 primary·8 cross-listed

01
Global optimization of harmonic oscillator basis in covariant density functional theory
B. Osei · A. V. Afanasjev · A. Dalbah
The present investigation focuses on the improvement of the accuracy of the description of binding energies within moderately sized fermionic basis. Using the solutions corresponding to infinite fermionic basis it was shown that in the case of meson exchange (ME) covariant energy density functionals (CEDFs) the global accuracy of the description of binding energies in the finite $N_{F} = 16 - 20$ bases can be drastically (by a factor ranging from $\approx 3$ up to $\approx 9$ dependent on the functional and $N_{F}$ ) improved by a global optimization of oscillator frequency of the basis. This is a consequence of the unique feature of the ME functionals in which with increasing fermionic basis size fermionic and mesonic energies approach the exact (infinite basis) solution from above and below, respectively. As a consequence, an optimal oscillator frequency $ℏ ω_{0}$ of the basis can be defined which provides an accurate reproduction of exact total binding energies by the ones calculated in truncated basis. This leads to a very high accuracy of the calculations in moderately sized $N_{F} = 20$ basis when mass dependent oscillator frequency is used: global rms differences $δ B_{r m s}$ between the binding energies calculated in infinite and truncated bases are only 0.025 MeV and 0.031 MeV for the NL5(Z) and DD-MEZ functionals, respectively. Optimized values of the oscillator frequency $ℏ ω_{0}$ are provided for three major classes of CEDFs, i.e. for density dependent meson exchange functionals, nonlinear meson exchange ones and point coupling functionals.
nucl-thPRC(2025)·5 citations
02
Perturbative renormalization of chiral nuclear forces at subleading order in 3S1-3D1 channel
Rui Peng🇨🇳 · Bingwei Long🇨🇳 · Fu-Rong Xu🇨🇳
We investigate renormalization of chiral nuclear forces in the coupled channel of 3S1-3D1 of nucleon-nucleon scattering. The one-pion exchange potential is treated nonperturbatively at leading order while subleading potentials are perturbations. Very much like the uncoupled channel of 3P0 , the singular attraction of one-pion exchange gives rise to the so-called genuine exceptional cutoffs, where artificial correlations between subleading contact operators emerge and they result in ill-defined values of the low-energy constants. To address this issue we follow the solution proposed for 3P0 in Ref. [1] and apply it to 3S1-3D1 . The truncation uncertainty of an effective field theory allows certain degrees of freedom in choosing renormalization conditions, or fitting schemes of the low-energy constants. By exploiting this freedom near the exceptional cutoffs, we are able to remove the said correlations. A much mitigated cutoff variation of the phase shifts, which is acceptable to the power counting, is thus obtained.
nucl-thPRC(2025)·6 citations
03
Concentrated valence nucleons transfer in heavy-ion collisions: implications for questing the stable superheavy elements
Zepeng Gao · Yinu Zhang · Long Zhu
The multinucleon transfer process is regarded as a promising pathway for producing the stable superheavy elements. However, the underlying mechanism, especially the possible transfer channels for sailing to the ``island of stability'' are poorly known. In this work, the time-dependent Hartree-Fock theory is used to investigate the collision dynamics of $^{136}$ Xe, $^{198}$ Pt, $^{238}$ U + $^{238}$ U reactions. A novel reaction channel of the concentrated valence nucleons (CVN) transferring is found in the collisions heading on the tips of $^{238}$ U. These nucleons are transferred with relatively short relaxation time and break the symmetry of nucleon exchange in the early reaction stage. In consequence, the mass equilibrium with relaxation time is deviated from the systematic behavior based on the macroscopic-microscopic potential energy surface. The CVN transfer channel shows promising prospect for producing neutron-rich superheavy nuclei. In this case, we also investigated the angular distributions of products from the CVN transfer channel in the reaction $^{238}$ U + $^{238}$ U with Tip-Side configuration, and the optimal detection angles are predicted.
nucl-thPRC(2025)·0 citations
04
$f$ and $p$ mode oscillation of proto-neutron stars with systematic variation of the nucleon effective mass
Atanu Guha🇰🇷 · Debashree Sen🇰🇷 · Hana Gil🇰🇷 · Hajime Togashi🇯🇵 · Chang Ho Hyun🇰🇷
We develop equation of state (EoS) of proto-neutron stars (PNSs) at various stages of evolution by varying entropy per baryon $S$ , using the Korea-IBS-Daegu-SKKU density functional model. With finite values for both temperature and density, we systematically investigate the influence of nucleon effective mass on EoS of PNSs, for different values of isoscalar effective mass $μ_{S}^{*}$ . For high entropy values, we aim to replicate conditions of failed core-collapse supernovae forming black holes. At each stage of evolution, structural and non-radial oscillation (fundamental $f$ -mode and first pressure $p_{1}$ -mode) properties are computed under isentropic conditions by varying $μ_{S}^{*}$ . We focus on the effects of $S$ and $μ_{S}^{*}$ on oscillation frequencies $f_{f}$ and $f_{p_{1}}$ adopting complete general relativistic formalism and Cowling approximation. Thermal effects reduce the values of $f_{f}$ and $f_{p_{1}}$ of PNSs compared to those of cold NSs, consequently detection of the former gets facilitated. For high-mass PNSs, this reduction is more pronounced for $f_{p_{1}}$ than $f_{f}$ . Moreover, lower values of $μ_{S}^{*}$ reduce $f_{f}$ and $f_{p_{1}}$ further. Universality of mass-scaled angular frequency ( $ω_{f} M$ ) with compactness ( $C$ ) and tidal deformability ( $Λ$ ) are obtained as non-linear fits that shift upwards (downwards) in $ω_{f} M - C$ ( $ω_{f} M - Λ$ ) plane for increasing values of $S$ . For fixed $S$ , the universality is also retained for variation of $μ_{S}^{*}$ . $S$ shows stronger correlation than $μ_{S}^{*}$ with structural and oscillation properties of (P)NSs. Strength of correlation of $S$ is more prominent with $f_{p_{1}}$ than $f_{f}$ while the trend is opposite for $μ_{S}^{*}$ . These findings suggest that detection of oscillation frequencies by upcoming GW detectors, could potentially indicate the evolutionary stage of a star during its transition from supernova to cold NS.
nucl-thPRD(2025)·5 citations
05
Exact Treatment of Continuum Couplings in Nuclear Optical Potentials via Feshbach Theory
Hao Liu🇨🇳 · Jin Lei🇨🇳 · Zhongzhou Ren🇨🇳
We present the first numerically exact implementation of full-coupling Feshbach theory for deriving effective optical potentials in nuclear reactions, overcoming long-standing computational barriers that previously necessitated weak-coupling approximations. By integrating Feshbach projection operators with the Continuum-Discretized Coupled-Channels (CDCC) method, we rigorously incorporate all continuum-continuum interactions, previously considered intractable, to extract dynamic polarization potentials that capture virtual excitations and absorption in reactions with weakly bound nuclei. Application to deuteron-induced reactions on $^{58}$ Ni demonstrates that our full-coupling effective potentials reproduce CDCC observables exactly, while weak-coupling and folding-model approaches show significant deviations. The method uniquely separates elastic breakup from breakup-fusion processes through the optical theorem, enabling precise determination of incomplete and complete fusion cross sections, critical for interpreting rare-isotope beam experiments at facilities like FRIB. The non-local polarization potentials provide insights into the energy-dependent interplay between reaction mechanisms, with our analysis suggesting an increasing relative importance of elastic breakup at higher energies while continuum absorption shows more complex behavior. This exact treatment eliminates systematic uncertainties from coupling approximations, providing predictive power for unstable nuclei far from stability where experimental data are scarce.
nucl-thPLB(2026)·5 citations
06
Thermo-coalescence model for Light Nuclei production in Relativistic Heavy-Ion Collisions
Arun Kumar Yadav🇮🇳 · Nachiketa Sarkar🇮🇳 · Sudhir Pandurang Rode🇷🇺 · Partha Pratim Bhaduri🇮🇳 · Abhijit Bhattacharyya🇮🇳 · Amaresh Jaiswal🇮🇳
We employ a hybrid approach to describe the light nuclei production mechanism where the nucleons are assumed to be thermally produced, and are allowed to form light nuclei using a coalescence prescription. In this approach, we first fit transverse momentum ( $p_{T}$ ) distribution of nucleons using hydro-inspired boost-invariant blast-wave model. The extracted parameters are then used to describe the deuteron $p_{T}$ spectra, along with two additional parameters that characterize the coalescence prescription employed in this study. We refer this combined approach as ``thermo-coalescence model'' and it is designed to study the deuteron production and describe the experimental measurements. In this work, we analyze the measured $p_{T}$ distribution of protons and deuterons from Pb-Pb collisions at the ALICE Collaboration at LHC. We also evaluate the $p_{T}$ -integrated deuteron yields using this approach and compare with experimental measurements. A Bayesian inference framework is employed to determine the best-fit parameters of the thermo-coalescence model. Finally, we estimate the traditionally used experimental coalescence parameter ( $B_{A}$ ) within our framework in order to establish a connection between our model and the conventional coalescence approach commonly used to relate experimental data with theoretical descriptions of light nuclei production.
nucl-thhep-phEPJC(2025)·0 citations
07
Antikaon absorption in the nuclear medium: the role of hadron self-energies and implications for kaonic atoms
J. Óbertová🇨🇿 · À. Ramos🇪🇸 · J. Mareš🇨🇿
A systematic study of all relevant in-medium effects on the total $K^{-}$ -nuclear potential is presented in this work. The $K^{-} N$ scattering amplitudes, including Pauli blocking effects and hadron self-energies (hyperons, nucleons, pions and kaons), are derived within a next-to-leading order chiral meson-baryon coupled-channel interaction model. These amplitudes are employed in a microscopic model of the $K^{-}$ -nuclear potential in symmetric nuclear matter that includes one-, two- and, when the kaons and pions are dressed, also multinucleon absorption processes. The potential is then applied in calculations of the strong energy shifts and widths of 64 measured kaonic atom levels. The comparison of the results of the full model that includes Pauli correlations and hadron self-energies with data provides $χ^{2} / d . p = 1.5$ , the lowest value obtained by a theoretical model to date and comparable with that of the best fitted phenomenological potentials. Furthermore, the calculated branching ratios for mesonic and non-mesonic absorption channels in kaonic carbon and kaonic neon are in good agreement with available data.
nucl-thPRC(2025)·5 citations
08
Proton-proton scattering on a quantum computer
Ratna Khadka · Gautam Rupak
Scattering of charged particles is ubiquitous in nuclear physics. We calculate the proton-proton $s$ -wave phase shift at low energy relevant to solar physics. The phase shift is calculated from the ratio of the regular and irregular solutions to the radial Schrödinger equation on a hard spherical wall boundary for the ground state. The ground state energy is calculated using a hybrid quantum-classical variational algorithm. A theory with short-ranged nuclear interaction in the presence of the long-ranged Coulomb force is used to describe the scattering. The theory is discretized on a spatial lattice for adaptation to the quantum computer in the second quantized language. The phase shifts at low momenta are accurately reproduced.
nucl-thquant-ph0 citations
09
The excited state of the $α$ -particle: a benchmark study
Pierre-Yves Duerinck🇧🇪 · Arnoldas Deltuva🇱🇹 · Jérémy Dohet-Eraly🇧🇪 · Mario Gattobigio🇫🇷 · Alejandro Kievsky🇮🇹 · Rimantas Lazauskas🇫🇷 · Darius Likandrovas🇱🇹 · Michele Viviani🇮🇹
A benchmark study is performed for the excited state of $^{4}$ He. When the Coulomb interaction is switched off, the $^{4}$ He nucleus exhibits a bound excited state in the vicinity of $p -^{3}$ H threshold. As the Coulomb interaction is gradually introduced, the excited state crosses the threshold and eventually becomes a resonant state. Using three numerical methods, we track the evolution of this excited state and determine the resonance energy and width. Comparisons of the theoretical predictions reveal a significant discrepancy with commonly used $R$ -matrix values based on the analysis of the experimental data. We explain the origin for this discrepancy. Additionally, the two-level energy spectrum of $^{4}$ He in the absence of the Coulomb force exhibits characteristics linked to Efimov physics, suggesting a reduced sensitivity to interaction details.
nucl-thPRC(2025)·3 citations

Affiliations

first authorsco-authorsvia INSPIRE