Nuclear Theory·nucl-th

Thursday·July 2, 2026

14 papers—8 primary·6 cross-listed

01
High-order perturbative calculations of nuclear ground states: Automated evaluation of many-body diagrams
Zhen Li🇩🇪 · Alexander Tichai🇩🇪 · Achim Schwenk🇩🇪 · Nadezda A. Smirnova🇫🇷
We advance the many-body perturbation theory (MBPT) calculations of the ground-state energy and radius of closed-shell nuclei beyond third order. Using automated diagram generation and evaluation up to fifth order, we present ground-state properties of selected closed-shell nuclei up to $^{78}$ Ni with two- and three-nucleon interactions derived from chiral effective field theory. A clear convergence trend is observed for the ground-state energy enabling calculations at improved accuracy. We further investigate in detail the decomposition of the fourth-order contributions. For the ground-state energy, the magnitude of the fourth-order contribution is typically less than half of the third order, and a typical cancellation among different classes of diagrams is observed. Finally, we perform a comprehensive comparison between MBPT and non-perturbative in-medium similarity renormalization group (IMSRG) calculations, with the goal to provide insight into many-body uncertainties associated with the IMSRG(2) truncation.
nucl-th1 citation
02
Spin Femtoscopy: A Framework for Revealing Genuine Spin Correlations
Kehao Zhang🇨🇳 · Xuan Wang🇨🇳 · Xiaofeng Luo🇨🇳
Spin correlations are among the most fundamental quantum observables in many-body systems, yet they remain difficult to access experimentally in relativistic heavy-ion collisions. Existing spin measurements, including hyperon polarization and vector-meson spin alignment, have revealed important single-particle spin phenomena, but genuine two-particle spin correlations in the produced hadronic system remain largely unexplored. Here we propose spin femtoscopy, a framework for accessing genuine two-particle spin correlations through spin-resolved femtoscopic measurements. The key principle is that different two-particle spin configurations can give rise to different femtoscopic correlation functions because of quantum statistics, spin-dependent final-state interactions. Using $ΛΛ$ pairs as a proof of principle, we exploit the self-analyzing weak decay of $Λ$ hyperons to construct spin-sensitive femtoscopic correlation functions with different singlet and triplet admixtures. We show that these observables provide experimental access to the spin-state populations of the pair and allow genuine spin correlations to be separated from spin-dependent femtoscopic mixing caused by quantum statistics and final-state interactions. This work extends femtoscopy from a probe of source geometry and final-state interactions to a framework for revealing the quantum spin structure of strongly interacting matter.
nucl-thhep-exhep-phnucl-ex+13 citations
03
Astrophysical S-factor Calculation for p-p Fusion Reaction
Arushi Sharma · Ishwar Kant · O.S.K.S. Sastri
The current S-factor calculations for weak pp interaction involve the determination of low-energy penetration probability using the bare Coulomb Gamow factor, which renders the nature and shape of actual interaction to be insignificant. In this work, the astrophysical S-factor is obtained utilizing the WKB action integral evaluated over the inverse scattering potential for the S-wave of pp-interaction, which does not involve bare Coulomb interaction in it. The np and pp inverse potentials are constructed using the phase function method by providing a reference potential consisting of three smoothly combined Morse functions, whose model parameters are optimized using a genetic algorithm to minimize the mean-squared error between the obtained and expected scattering phase shifts. The overlap integral between the bound-state deuteron and the scattering state of pp S-wave has been evaluated at different energies all the way up to 0.0001 MeV, and corresponding fusion cross-sections are determined. The WKB action integral has been computed at all energies without any approximations. Finally, the S-factor at various energies are calculated, and S(0) has been obtained using a supervised neural network. The value of S(0) obtained using our methodology involving complete evaluation of WKB action integral without approximations is $(0.1261 \pm 0.0043) \times 1 0^{- 25}$ , which is almost one order of magnitude lower than the currently accepted values using various methods. The inverse potentials constructed using the reference potential approach, which does not involve explicit consideration of nuclear $&$ Coulomb interaction, resulting in a finite range of pp-interaction, have been successful in providing a new estimate for the astrophysical s-factor that depends on the nature and shape of the actual potentials.
nucl-th0 citations
04
Long Time Energy Oscillation Between Electron Shell and Nucleus in $^{229}$ Th Ions and Coherent Electron Bridge for Nuclear Quantum Battery
E. V. Tkalya🇷🇺
The electron shell of the Thorium ion with the $M$ 1(8.4~eV) transition between levels and the doublet of the $^{229}$ Th nucleus ground state with the similar transition represent two qubits spatially inserted one within the other. In the case of relative proximity of the energies of these transitions, weakly damped energy oscillations can be excited between qubits, namely, multiple coherent energy transfer from the electron shell to the nucleus and vice versa. This process in the $^{229}$ Th ions does not require resonant (within the width of the levels) coincidence of the transition energies due to the relatively high interaction energy of the electron and nuclear currents. The electron shell ``breathes'', periodically decreasing and increasing in size. The effect can be observed in an ion trap by the intensity of light scattered by thorium-229 ions. This extends the energy range for the $^{229 m}$ Th $(3/ 2^{+}, 8.4$ ~eV) isomer excitation via an electron bridge. Furthermore, the system under consideration is transformed into a nuclear quantum battery when exposed to coherent laser radiation. To ``charge'' the battery, i.e. to excite $^{229 m}$ Th, one can use developed methods for charging quantum batteries, in particular, coherent excitation of the electron shell followed by coherent transfer of excitation energy to the nucleus (the coherent electron bridge). This opens the way for the design of the $^{229}$ Th nuclear quantum battery at the current level of technological development.
nucl-th0 citations
05
Elastic deuteron-deuteron scattering within Nuclear Lattice Effective Field Theory
Helen Meyer🇩🇪 · Serdar Elhatisari🇹🇷 · Fabian Hildenbrand🇩🇪 · Ulf-G. Meißner🇩🇪
We calculate low-energy deuteron-deuteron scattering in the spin-quintet $^{5} S_{2}$ channel using nuclear lattice effective field theory. The calculation combines chiral interactions at next-to-next-to-next-to-leading order, implemented through wavefunction matching, with the adiabatic projection method. Because the radial cluster basis develops small norm-matrix eigenvalues at large Euclidean projection time, we investigate two stabilization procedures: Tikhonov regularization and projection onto well-resolved norm eigenmodes. The two procedures yield consistent Coulomb-subtracted phase shifts within their statistical and numerical uncertainties. A Coulomb-modified effective-range analysis gives $^{5} a_{dd} = (12.96 \pm 0.26) fm$ and $^{5} r_{dd} = (3.62 \pm 0.79) fm$ . The phase shifts are more negative, and the scattering length is substantially larger than in previous calculations, corresponding to a stronger effective repulsion in the $^{5} S_{2}$ channel. These results provide a first nuclear-lattice benchmark for deuteron-deuteron scattering and establish a basis for future coupled-channel calculations of the deuteron-induced reactions relevant to big-bang nucleosynthesis.
nucl-thhep-lat0 citations
06
Dipolar flow of identified hadrons at mid-rapidity using transport models
Abhisek Praharaj🇮🇳 · Aradhana Panday🇮🇳 · Sandeep Chatterjee🇮🇳 · Md Nasim
We report a transport model study of the rapidity even component of dipolar flow, $v_{1}^{even}$ , for identified charged hadrons at mid-rapidity in Au+Au collisions at $s_{N N} = 27 - 200$ GeV. The analysis is performed using the AMPT model, with comparisons to HIJING to quantify non-flow contributions. The $v_{1}^{even}$ of identified hadrons ( $π$ , $K$ , and $p$ ) shows no significant difference between particles and anti-particles at $s_{N N} = 200$ GeV. However, a clear splitting between proton and anti-proton $v_{1}^{even}$ develops with decreasing beam energy, while no corresponding difference is observed for mesons ( $π^{\pm}$ and $K^{\pm}$ ). A comparison of the AMPT string melting and default configurations shows that the splitting arises only in the string melting scenario, where partonic interactions and quark coalescence play a dominant role. These results indicate that the proton-antiproton difference in $v_{1}^{even}$ is sensitive to baryon transport and early-stage partonic dynamics. Our study highlights the potential of identified-particle $v_{1}^{even}$ measurements at RHIC Beam Energy Scan energies as a novel probe of baryon stopping and the evolution of the partonic medium.
nucl-th0 citations
07
Purifying one-neutron removal as a probe of single-particle strength
Erxi Xiao · Guangshuai Li · Yu Yang · Long Zhu · Jianwei Zhao · Jun Su · Baohua Sun
One-neutron removal reactions exhibit a strong proton-neutron asymmetry dependence in the inclusive reduction factor $R_{s}$ , a long-standing issue that has been discussed in terms of both possible intrinsic isospin dependence of single-particle strength and reaction-mechanism effects. We address this issue by reframing inclusive removal as a coupled fast-dynamics and deexcitation process, and by validating this transport-deexcitation chain against a global, mutually constraining data set. Confronting 73 one-neutron removal cross sections and 28 residue parallel-momentum distributions with isospin-dependent quantum molecular dynamics followed by GEMINI evaporation shows that the apparent $R_{s}$ - $Δ S$ trend is correlated with evaporation feeding and evaporation loss. By subtracting the feeding contribution and correcting for the loss component in the measured cross sections, we construct a purified reduction factor $R_{dir}$ , that more closely reflects single-particle strength than the inclusive $R_{s}$ . The resulting $R_{dir}$ exhibits a much weaker $Δ S$ dependence within current uncertainties, consistent with the weak isospin-asymmetry dependence observed in nucleon-transfer and quasifree-knockout systematics.
nucl-thPLB(2026)·0 citations
08
Semi-regularised three-body pseudopotential for mean-field and beyond-mean-field calculations
Valentin Guillon🇫🇷 · Michael Bender🇫🇷 · Karim Bennaceur🇫🇷 · Philippe Da Costa🇫🇷
We derive the most general form of a local leading-order semi-regularised three-body pseudopotential. This particular form of pseudopotential is developed with the aim of generating contributions to the nuclear energy density functional (EDF) in both the particle-hole and particle-particle channels and, hence, to be usable in mean-field and beyond-mean-field calculations without ambiguities or mathematical difficulties. Once the EDF is obtained, analytical expressions of commonly considered properties of infinite nuclear matter are provided. Finally, the structure of the EDF and the associated mean fields are given for spherically-symmetric systems.
nucl-th0 citations

Affiliations

first authorsco-authorsvia INSPIRE