Nuclear Theory·nucl-th

Thursday·February 13, 2025

9 papers—8 primary·1 cross-listed

01
Building Neutron Stars with the MUSES Calculation Engine
Mateus Reinke Pelicer🇺🇸 · Nikolas Cruz-Camacho🇺🇸 · Carlos Conde🇺🇸 · David Friedenberg🇺🇸 · Satyajit Roy🇺🇸 · Ziyuan Zhang🇺🇸 · T. Andrew Manning🇺🇸 · Mark G. Alford🇺🇸 · Alexander Clevinger🇺🇸 · Joaquin Grefa🇺🇸 · Roland Haas🇺🇸 · Alexander Haber🇺🇸 and 16 other authors
Exploring the equation of state of dense matter is an essential part of interpreting the observable properties of neutron stars. We present here the first results for dense matter in the zero-temperature limit generated by the MUSES Calculation Engine, a composable workflow management system that orchestrates calculation and data processing stages comprising a collection of software modules designed within the MUSES framework. The modules presented in this work calculate equations of state using algorithms spanning three different theories/models: (1) Crust Density Functional Theory, valid starting at low densities, (2) Chiral Effective Field Theory, valid around saturation density, and (3) the Chiral Mean Field model, valid beyond saturation density. Lepton contributions are added through the Lepton module to each equation of state, ensuring charge neutrality and the possibility of $β$ -equilibrium. Using the Synthesis module, we match the three equations of state using different thermodynamic variables and different methods. We then couple the complete equation of state to a novel full-general-relativity solver (QLIMR) module that calculates neutron star properties. We find that the matching performed using different thermodynamic variables affects differently the range obtained for neutron star masses and radii (although never beyond a few percent difference). We also investigate the universality of equation of state-independent relations for our matched stars. Finally, for the first time, we use the Flavor Equilibration module to estimate bulk viscosity and flavor relaxation charge fraction and rates (at low temperature) for Chiral Effective Field Theory and the Chiral Mean Field model.
nucl-thastro-ph.HEgr-qchep-ph+1PRD(2025)·30 citations
02
Inelastic neutrino-nucleus scattering off $^{203/205}$ Tl in terms of the nuclear recoil energy using a hybrid nuclear model
Matti Hellgren🇫🇮 · Dimitrios K. Papoulias🇪🇸 · Jouni Suhonen🇫🇮
Nuclear structure calculations in the context of a novel hybrid nuclear model, combining the nuclear shell model and the microscopic quasiparticle-phonon model are presented. The predictivity of the hybrid model is tested by computing inelastic neutral-current neutrino-nucleus scattering cross sections off the stable thallium isotopes. The cross sections are presented in terms of the incoming neutrino energy, taking also into account the effect of nuclear recoil energy. Also reported are the expected event rates assuming neutrinos emerging from pion-decay at rest and the diffuse supernova neutrino background. Regarding solar neutrino rates, new results are presented in the context of the hybrid model and compared with previously reported results based solely on nuclear shell model calculations, demonstrating the improved accuracy of the adopted hybrid model at higher neutrino energies.
nucl-thhep-phPLB(2025)·2 citations
03
Benchmarking nuclear matrix elements of $0 ν β β$ decay with high-energy nuclear collisions
Yi Li🇨🇳 · Xin Zhang🇯🇵 · Giuliano Giacalone🇨🇭 · Jiangming Yao🇨🇳
Reducing uncertainties in the nuclear matrix elements (NMEs) remains a critical challenge in designing and interpreting experiments aimed at discovering neutrinoless double beta ( $0 ν β β$ ) decay. Here, we identify a class of observables, distinct from those employed in low-energy nuclear structure applications, that are strongly correlated with the NMEs: momentum correlations among hadrons produced in high-energy nuclear collisions. Focusing on the $^{150}$ Nd $\to$ $^{150}$ Sm transition, we combine a Bayesian analysis of the structure of $^{150}$ Nd with simulations of high-energy $^{150}$ Nd+ $^{150}$ Nd collisions. We reveal prominent correlations between the NMEs and features of the quark-gluon plasma (QGP) formed in these processes, such as spatial gradients and anisotropies, which are accessible via collective flow measurements. Our findings demonstrate collider experiments involving $0 ν β β$ decay candidates as a platform for benchmarking theoretical predictions of the NMEs.
nucl-thhep-phnucl-exPRL(2025)·17 citations
04
Directly probing existence of $α$ -cluster structure in $^{20}$ Ne by relativistic heavy-ion collisions
Lu-Meng Liu🇨🇳 · Hai-Cheng Wang🇨🇳 · Song-Jie Li🇨🇳 · Chunjian Zhang🇨🇳 · Jun Xu🇨🇳 · Zhong-Zhou Ren🇨🇳 · Jiangyong Jia🇺🇸 · Xu-Guang Huang🇨🇳
Can relativistic heavy-ion collisions only probe the global shape of colliding nuclei, or their detailed internal structure as well? Taking $^{20}$ Ne as an example, we attempt to directly probe its internal $α$ -cluster structure, by comparing experimentally measured observables in collisions at relativistic energies from density distributions of $^{20}$ Ne with and without $α$ -cluster structure. Since the two density distributions give the same nucleus size and deformation, they lead to similar mid-rapidity observables. However, the $α$ -cluster structure may considerably reduce the free spectator nucleon yield and enhance the spectator light nuclei yield, as a result of more compact initial phase-space distribution of nucleons inside $α$ clusters. We propose to measure the scaled yield ratio of free spectator neutrons to charged particles with mass-to-charge ratio $A / Z = 3$ , 3/2, and 2 in ultra-central $^{20}$ Ne+ $^{20}$ Ne collisions, which is found to be reduced by about $25%$ at $s_{NN} = 7$ TeV and about $20%$ at $s_{NN} = 200$ GeV with $α$ -cluster structure in $^{20}$ Ne. This scaled yield ratio thus serves as a robust and direct probe of the existence of $α$ -cluster structure in $^{20}$ Ne free from the uncertainty of mid-rapidity dynamics.
nucl-thhep-exnucl-exPRC(2025)·15 citations
05
Fixing effective range parameters in elastic $α$ - $^{12}$ C scattering: an impact on resonant $2_{4}^{+}$ state of $^{16}$ O and $S_{E 2}$ factor of $^{12}$ C( $α$ , $γ$ ) $^{16}$ O
Shing-Ichi Ando
Elastic $α$ - $^{12}$ C scattering for $l = 2$ and $E 2$ transition of radiative $α$ capture on $^{12}$ C, $^{12}$ C( $α$ , $γ$ ) $^{16}$ O, are studied in cluster effective field theory. Due to the problem in fixing the asymptotic normalization coefficient (ANC) of the subthreshold $2_{1}^{+}$ state of $^{16}$ O, equivalently, the effective range parameters of the $2_{1}^{+}$ state, from the elastic scattering data, we introduce the conditions that lead to a large value of the ANC. In addition, $d$ -wave phase shift data of the elastic scattering up to the $α$ energy, $E_{α} = 10$ ~MeV, which contain resonant $2_{4}^{+}$ state of $^{16}$ O, are also introduced in the study. Applying the conditions, the parameters of the $S$ matrix of the elastic scattering for $l = 2$ are fitted to the phase shift data, and the fitted parameters are employed in the calculation of astrophysical $S_{E 2}$ factor of $^{12}$ C( $α$ , $γ$ ) $^{16}$ O; we extrapolate the $S_{E 2}$ factor to the Gamow-peak energy, $E_{G} = 0.3$ ~MeV. We find that the conditions lead to significant effects in the observables of the $2_{4}^{+}$ state of $^{16}$ O and the estimate of the $S_{E 2}$ factor at $E_{G}$ and confirm that the ANC of the $2_{1}^{+}$ of $^{16}$ O cannot be determined by the phase shift data for $l = 2$ .
nucl-thnucl-exCPC(2025)·6 citations
06
Complete set of observables in pseudo-scalar meson photoproduction -- Controversy solved
A. Švarc🇭🇷
The long-standing debate over whether the complete set of observables in pseudo-scalar meson photoproduction consists of eight or merely four elements continues to persist. From the perspective of amplitude analysis, it is argued that all eight observables are necessary to completely determine the others. On the other hand, proponents of partial-wave analysis, working with theoretically precise data of infinite accuracy, claim that only four observables are needed. However, this claim is not acceptable from an experimental viewpoint, as all data in the real world contain some uncertainty. This paper illustrates that the controversy is artificial and is due to additional mathematical assumptions used in partial-wave analysis. Our research advances this discussion by moving from exact synthetic numerical data to also synthetic, but more realistic data in partial-wave analysis and shows that the claimed reduction in observables is unjustified. Consequently, the final conclusion is that the complete set of observables in pseudo-scalar meson photoproduction, whether using amplitude analysis or partial-wave analysis with practical data, must consist of eight observables.
nucl-thnucl-exActa Phys.Polon.B(2026)·1 citation
07
$ϕ$ meson in nuclear matter and atomic nuclei
Arpita Mondal🇮🇳 · Amruta Mishra🇮🇳
The properties (masses and decay widths) of the $ϕ$ meson are investigated in nuclear matter from the $ϕ$ meson self-energy, using the tree-level $ϕ K K ˉ$ Lagrangian, and, incorporating in-medium masses of (anti)kaons calculated within the quark meson coupling (QMC) model. These mass shifts and decay widths are incorporated in the Breit-Wigner spectral function of the $ϕ$ meson to calculate the production cross-section of $ϕ$ in asymmetric nuclear matter. Considerable modifications to the production cross-section are observed at normal nuclear matter density, driven by the in-medium mass reduction and the increase in the decay width of $ϕ$ meson. The potential experienced by $ϕ$ meson in nuclear matter is used to study the possibility of formation of the $ϕ$ mesic bound state with atomic nuclei. We explore the potential formation of $ϕ$ -mesic bound states in $^{4} He$ , $^{12} C$ , $^{16} O$ , $^{40} Ca$ , $^{90} Zr$ , $^{197} Au$ and $^{208} Pb$ nuclei by investigating their binding energies and absorption widths based on the corresponding $ϕ$ -nucleus potentials. Our study shows shallow bound states with the light nuclei and deeply bound states in heavy nuclei. Among the investigated nuclei, a particularly distinct signal for a $ϕ$ -mesic bound state is identified in $^{16} O$ , suggesting its potential experimental observability. The work provides valuable insights into $ϕ$ meson interactions in infinite nuclear matter and the potential formation of exotic $ϕ$ -mesic nuclear states, offering promising probes for strongly interacting matter in the upcoming experiments at J-PARC, JLab, and $P ˉ ANDA$ @FAIR physics program.
nucl-thhep-phPRD(2025)·5 citations
08
A variation on "compositeness" (including higher partial waves)
Peter C. Bruns
The ``spatial interpretation of compositeness'', presented and discussed in [1,2] in the context of non-relativistic potential scattering, is extended to higher partial waves. A particular set of basis states is used to arrive at a slightly different perspective on the derivation and interpretation of ``compositeness'' usually given in the literature.
nucl-th1 citation
09
Scale Setting and Strong Coupling Determination in the Gradient Flow Scheme for 2+1 Flavor Lattice QCD
Rasmus Larsen🇩🇪 · Swagato Mukherjee🇺🇸 · Peter Petreczky🇺🇸 · Hai-Tao Shu🇨🇳 · Johannes Heinrich Weber🇩🇪
We report on the determination of the gradient flow scales in $N_{f} = 2 + 1$ QCD using highly improved staggered quark (HISQ) ensembles generated by the HotQCD Collaboration for bare gauge couplings ranging from $β = 6.423$ to $8.400$ . Using bottomonium splittings, kaon decay constant, the decay constant of unmixed $η_{s}$ meson and the $ϕ$ meson mass we obtained the values of the gradient flow scales in physical units, $t_{0} = 0.14428 (48)$ ~fm and $w_{0} = 0.17391 (52)$ ~fm. Using the same physical inputs we revisit the determination of the potential $r_{1}$ scale and find $r_{1} = 0.3112 (24)$ ~fm. As a byproduct of our study we obtain the running of the gauge coupling in the gradient flow scheme. We find that within the uncertainties the running of the gradient flow coupling obtained on the lattice is compatible with the perturbative results up to flow radius $8 τ_{F} = 0.15$ fm.
↳ hep-lathep-phhep-thnucl-th9 citations

Affiliations

first authorsco-authorsvia INSPIRE