Nuclear Theory·nucl-th

Wednesday·October 15, 2025

11 papers—4 primary·7 cross-listed

01
The role of the overlap function in describing angular distributions of single-nucleon transfer reactions
M. R. Xie · J.G. Li · N. Keeley · N. Michel · W. Zuo
Single-nucleon transfer reactions offer a valuable way to probe nuclear structure. We explore the effect of directly introducing overlap functions computed using the Gamow shell model (GSM) into reaction calculations, taking the $⟨^{7} Li ∣ \protect^{6} He + p ⟩$ single proton overlap as a case study. By incorporating both inter-nucleon correlations and continuum coupling, the GSM provides accurate overlap functions in both interior and asymptotic regions, together with the corresponding spectroscopic factors (SFs). These theoretical SFs and overlap functions were included in a coupled channels Born approximation analysis of the $^{6}{\rm He}(d,n)^7{\rm Li}$ transfer reaction. Overlap functions derived from \textit{ab initio} no-core shell model (NCSM) calculations as well as standard single-particle (s.p.) wave functions were also considered for comparison. Our results reveal significant differences between the calculated angular distributions when employing theoretical SFs with standard s.p.\ wave functions compared to the full theoretical overlap functions. Discrepancies were also observed between angular distributions calculated with GSM and NCSM overlap functions, highlighting the importance of internal structure and correct asymptotic behavior in reliable reaction calculations. The GSM overlap functions also provided a good description of the $^{208}$ Pb( $^{7}$ Li, $^{6}$ He) $^{209}$ Bi reaction when included in a coupled reaction channels calculation.
nucl-thPRC(2026)·1 citation
02
Perturbative $χ$ EFT calculations of the deuteron and triton up to N $^{2}$ LO
Oliver Thim🇸🇪 · Andreas Ekström🇸🇪 · Christian Forssén🇸🇪
We extend previous studies of the deuteron and triton ground-state energies to next-to-next-to-leading order (N $^{2}$ LO) in chiral effective field theory, employing a power counting in which subleading interactions are treated perturbatively. Triton calculations are performed using the no-core shell model, and we demonstrate converged perturbative results for regulator cutoffs up to $Λ \approx 1200$ MeV. We analyze exceptional cutoffs in the $^{3} P_{0}$ and $^{3} S_{1} -^{3} D_{1}$ nucleon-nucleon channels and find a resulting cutoff dependence in the triton ground-state energy at N $^{2}$ LO. The effect associated with the exceptional cutoff in the $^{3} P_{0}$ channel can be mitigated by redefining the leading-order wave function within the freedom allowed by the effective field theory. The same approach applied in the $^{3} S_{1} -^{3} D_{1}$ channel remedies the effect of this exceptional cutoff on the ground state energy of the deuteron, but not for the triton.
nucl-thPRC(2025)·6 citations
03
Unlocking the initial neutron density distribution from the two-pion HBT correlation function in heavy-ion collisions
Pengcheng Li🇨🇳 · Manzi Nan🇨🇳 · Haojie Zhang🇨🇳 · Junhuai Xu🇨🇳 · Xilong Xiang🇨🇳 · Yijie Wang🇨🇳 · Yongjia Wang🇨🇳 · Gaochan Yong🇨🇳 · Tadaaki Isobe🇯🇵 · Zhigang Xiao🇨🇳 · Qingfeng Li🇨🇳
Revealing the neutron density distribution in the nucleus is one of the crucial tasks of nuclear physics. Within the framework of the ultrarelativistic quantum molecular dynamic model followed by a correlation afterburner program, we investigate the effects of the initial neutron density distribution on the charged-pion yield ratio $π^{-} / π^{+}$ , the two-pion momentum correlation function, and the emission source dimension. It is found that the $π^{-} / π^{+}$ ratio is sensitive to the initial neutron density distribution and the impact parameter, especially for collisions at large impact parameter. However, the charge splitting in the correlation functions between positively $π^{+} π^{+}$ and negatively $π^{-} π^{-}$ , as well as the source radii and volumes extracted exhibit a stronger dependence on the initial neutron density distribution, but a weaker dependence on the impact parameter. The present study highlights that $π^{+} π^{+}$ and $π^{-} π^{-}$ correlation functions in heavy-ion collisions could be used to probe the initial neutron density distribution of nuclei.
nucl-thPLB(2025)·5 citations
04
Transport properties of stochastic fluids
Chandrodoy Chattopadhyay · Josh Ott · Thomas Schaefer · Vladimir V. Skokov
We study heat conduction and momentum transport in the context of stochastic fluid dynamics. We consider a fluid described by model H in the classification of Hohenberg and Halperin. We study both non-critical and critical fluids, and we investigate transport properties in two as well as three dimensions. Our results are based on numerical simulations of model H using a Metropolis algorithm, and we employ Kubo relations to extract transport coefficients. We observe the expected logarithmic divergence of the shear viscosity in a two-dimensional non-critical fluid. At a critical point, we find that the transport coefficients exhibit power-law scaling with the system size $L$ . The strongest divergence is seen for the thermal conductivity $κ$ in two dimensions. We find $κ \sim L^{x_{κ}}$ with $x_{κ} = 1.6 \pm 0.1$ . The divergence is weaker in three dimensions, $x_{κ} = 1.25 \pm 0.3$ , and the scaling exponent for the shear viscosity, $x_{η}$ , is significantly smaller than $x_{κ}$ in both two and three dimensions.
nucl-thcond-mat.quant-gashep-phPRD(2025)·3 citations

Affiliations

first authorsco-authorsvia INSPIRE

The role of the overlap function in describing angular distributions of single-nucleon transfer reactions

Perturbative χEFT calculations of the deuteron and triton up to N2LO

Unlocking the initial neutron density distribution from the two-pion HBT correlation function in heavy-ion collisions

Transport properties of stochastic fluids

Affiliations

Perturbative $χ$ EFT calculations of the deuteron and triton up to N $^{2}$ LO