Nuclear Theory·nucl-th

Friday·August 2, 2024

13 papers—7 primary·6 cross-listed

01
The art of modeling nuclear reactions with weakly bound nuclei: status and perspectives
A.M. Moro · J. Casal · M. Gomez-Ramos
We give an overview of the theoretical description of nuclear reactions involving weakly-bound nuclei. Some of the more widespread reaction formalisms employed in the analysis of these reactions are briefly introduced, including various recent developments. We put special emphasis on the continuum-discretized coupled-channel (CDCC) method and its extensions to incorporate core and target excitations as well as its application to three-body projectiles. The role of the continuum for one-nucleon transfer reactions is also discussed. The problem of the evaluation of inclusive breakup cross sections is addressed within the Ichimura-Austern-Vincent (IAV) model. Other methods, such as those based on a semiclasical description of the scattering process, are also briefly introduced and some of their applications are discussed and a brief discussion on topics of current interest, such as nucleon-nucleon correlations, uncertainty evaluation and non-locality is presented.
nucl-thnucl-exEPJA(2025)·11 citations
02
Pairing phase transition in the odd-A nuclei: identification and classification
Yumeng Wang · Yuhang Gao · Lang Liu
The investigation into the pairing phase transition in the odd-A nucleus 161Dy utilizes a sophisticated blend of covariant density functional theory and the shell-model-like approach. It is discerned that variations in thermodynamic quantities at the critical temperature do not exclusively align with pairing phase transitions. The presence of an S-shaped heat capacity curve, often interpreted as an indication of such transitions, does not offer a definitive confirmation. Additional factors, including the blocking effect, can modify the heat capacity curve and impede the transition process. The pairing phase transition in 161Dy, occurring around 0.7 to 1.0 MeV, is unequivocally characterized as a first-order transition. Furthermore, an exploration into the impact of varying strengths of pairing correlations on these transitions reveals a nonlinear relationship, adding complexity to the transition dynamics.
nucl-thnucl-exCPC(2024)·2 citations
03
Improving relativistic energy density functionals with tensor couplings
Stefan Typel · Shalom Shlomo
Energy density functionals (EDFs) have been used extensively with great success to calculate properties of nuclei and to predict the equation of state (EOS) of dense nuclear matter. Besides non-relativistic EDFs, mostly of the Skyrme or Gogny type, relativistic EDFs of different types are in widespread use. In these latter approaches, the effective in-medium interaction is described by an exchange of mesons between nucleons. In most cases, only minimal meson-nucleon couplings are considered. The effects of additional tensor couplings were rarely investigated. In this work, a new relativistic EDF with tensor couplings and density dependent minimal meson-nucleon couplings will be presented. The parameters of the model are determined using a carefully selected set of experimental data with realistic uncertainties that are determined self-consistently. Predictions for various nuclear observables, the nuclear matter equation of state, and properties of neutron stars are discussed.
nucl-thEPJA(2024)·8 citations
04
Bayesian analysis of (3+1)D relativistic nuclear dynamics with the RHIC beam energy scan data
Syed Afrid Jahan🇺🇸 · Hendrik Roch🇺🇸 · Chun Shen🇺🇸
This work presents a Bayesian inference study for relativistic heavy-ion collisions in the Beam Energy Scan program at the Relativistic Heavy-Ion Collider. The theoretical model simulates event-by-event (3+1)D collision dynamics using hydrodynamics and hadronic transport theory. We analyze the model's 20-dimensional posterior distributions obtained using three model emulators with different accuracy and demonstrate the essential role of training an accurate model emulator in the Bayesian analysis. Our analysis provides robust constraints on the Quark-Gluon Plasma's transport properties and various aspects of (3+1)D relativistic nuclear dynamics. By running full model simulations with 100 parameter sets sampled from the posterior distribution, we make predictions for $p_{T}$ -differential observables and estimate their systematic theory uncertainty. A sensitivity analysis is performed to elucidate how individual experimental observables respond to different model parameters, providing useful physics insights into the phenomenological model for heavy-ion collisions.
nucl-thhep-phPRC(2024)·35 citations
05
Universal relationships for neutron stars from perturbative approach
Debasis Atta🇮🇳 · Vinay Singh🇮🇳 · D. N. Basu🇮🇳
The universal relationships for compact stars have been investigated employing perturbative approach using canonical (APR) and Brussels-Montreal Skyrme (BSk22, BSk24, BSk26) equations of state describing hadronic matter of neutron stars. The neutron star matter has been considered to be $β$ -equilibrated neutron-proton-electron-muon matter at the core with a rigid crust. The multipole moments of a slowly rotating neutron star characterize its external gravitational field. These variables are dependent on the interior structure of the neutron star described by the equation of state of the neutron star matter. The properties of neutron stars, such as the mass, the radius, the dimensionless moment of inertia, the compactness, the Love number, the dimensionless tidal deformability and the dimensionless quadrupole moment have been calculated and relations among these quantities have been explored. It is found that most of these relations do not depend sensitively on the details of the internal structure of neutron stars. Such universality implies that the measurement of a single quantity appearing in a universal relation would automatically provide information about the others, notwithstanding the fact that those may not be accessible observationally. These can be used to estimate deformability of compact stars through moment of inertia measurements, to quantify spin in binary inspirals by breaking degeneracies in the detection of gravitational waves and test General Relativity in a way that is independent of nuclear structure.
nucl-thNew Astron.(2025)·4 citations
06
Subspace-projected multireference covariant density functional theory
X. Zhang🇨🇳 · C. C. Wang🇨🇳 · C. R. Ding🇨🇳 · J. M. Yao🇨🇳
Multireference density functional theory (MR-DFT) has been a pivotal method for studying nuclear low-lying states and neutrinoless double-beta ( $0 ν β β$ ) decay. However, quantifying their theoretical uncertainties has been a significant challenge due to the computational demands. This study introduces a subspace-projected covariant density functional theory (SP-CDFT), which efficiently emulates MR-CDFT calculations for nuclear low-lying states. This approach leverages the eigenvector continuation method combined with the quantum-number projected generator coordinate method, based on a relativistic energy density functional (EDF). We apply SP-CDFT to investigate the correlations among the physical quantities of nuclear matter, nuclear low-lying spectroscopy, and the nuclear matrix elements (NMEs) of $0 ν β β$ decay in the two heaviest candidate nuclei. Our findings reveal generally strong correlations between the NMEs of $0 ν β β$ decay and the excitation energy of the $2_{1}^{+}$ state, as well as the $E 2$ transition strength, although these correlations vary significantly among nuclei. This work also paves the way for refining nuclear EDF parameters using spectroscopic data.
nucl-thcond-mat.str-elhep-phnucl-exPRC(2025)·10 citations
07
The Smile of Cheshire Cat At High Density
Mannque Rho🇫🇷
Baryons in finite nuclei, nuclear matter and dense compact-star matter are described in terms of Cheshire Cat for QCD. A potential conceptual link, admittedly short in mathematical rigor, between their manifestations is made by what's called Cheshire Cat Principle. Put in terms taken ``dual" to QCD variables, going to very high density exposes quantum Hall droplets -- or pancakes -- at which the dilaton-limit fixed point with $g_{A} \to 1$ , $f_{π} \to f_{χ}$ -- where $f_{π}$ and $f_{χ}$ are respectively the pion and dilaton decay constants -- and the baryon parity-doubling are reached. This scenario suggests a thus-far totally unexplored structure of dual baryonic matter at high density which does neither require nor rule out (rapid) first-order phase transitions from hadrons to quarks in the core of compact stars on the verge of gravitational collapse.
nucl-thhep-phJ.Subatomic Part.Cosmol.(2024)·6 citations
08
Quantum Computing Universal Thermalization Dynamics in a (2+1)D Lattice Gauge Theory
Niklas Mueller🇺🇸 · Tianyi Wang🇺🇸 · Or Katz🇺🇸 · Zohreh Davoudi🇺🇸 · Marko Cetina🇺🇸
Simulating non-equilibrium phenomena in strongly-interacting quantum many-body systems, including thermalization, is a promising application of near-term and future quantum computation. By performing experiments on a digital quantum computer consisting of fully-connected optically-controlled trapped ions, we study the role of entanglement in the thermalization dynamics of a $Z_{2}$ lattice gauge theory in 2+1 spacetime dimensions. Using randomized-measurement protocols, we efficiently learn a classical approximation of non-equilibrium states that yields the gap-ratio distribution and the spectral form factor of the entanglement Hamiltonian. These observables exhibit universal early-time signals for quantum chaos, a prerequisite for thermalization. Our work, therefore, establishes quantum computers as robust tools for studying universal features of thermalization in complex many-body systems, including in gauge theories.
↳ quant-phhep-lathep-phnucl-thNature Commun.(2025)·60 citations
09
An alternative way to decipher the nature of the doubly charmed tetraquark $T_{cc} (3875)^{+}$ : its antiparticle $T_{c ˉ c ˉ} (3875)^{-}$ photoproduction off nuclei near threshold
E. Ya. Paryev🇷🇺
We study the inclusive photoproduction of $T_{c ˉ c ˉ} (3875)^{-}$ mesons (which are the antiparticles of the doubly charmed tetraquarks $T_{cc} (3875)^{+}$ discovered recently by the LHCb Collaboration) from nuclei in the near-threshold energy region within the nuclear spectral function approach by considering incoherent direct ( $γ p (n) \to D^{+} (D^{0}) T_{c ˉ c ˉ} (3875)^{-} Λ_{c}^{+}$ ) photon--nucleon $T_{c ˉ c ˉ} (3875)^{-}$ creation processes as well as five possible different scenarios for their internal structure with the main goal of clarifying the possibility to decipher this structure (and, hence, that of $T_{cc} (3875)^{+}$ ) in photoproduction via integral and differential observables. We calculate the absolute and relative excitation functions for $T_{c ˉ c ˉ} (3875)^{-}$ production off $^{12}$ C and $^{184}$ W target nuclei at near-threshold photon beam energies of 30--38 GeV, the absolute differential cross sections for their production off these target nuclei at laboratory polar angles of 0 $^{\circ}$ --10 $^{\circ}$ as well as the A and momentum dependences of the relative (transparency ratios) cross sections for $T_{c ˉ c ˉ} (3875)^{-}$ production at photon energy of 35 GeV within the adopted scenarios for the $T_{c ˉ c ˉ} (3875)^{-}$ meson intrinsic structure. We demonstrate that the absolute and relative observables considered show a certain sensitivity to these scenarios. Therefore, the measurement of such observables in future experiments at the proposed high-luminosity electron-ion colliders EIC and EicC in the US and China in the near-threshold energy region might shed light on the $T_{cc} (3875)^{+}$ internal structure.
↳ hep-phhep-exnucl-exnucl-thInt.J.Mod.Phys.A(2024)·3 citations
10
Second-order nonlocal shifts of scattered wave-packets: What can be measured by Goos-Hänchen and Imbert-Fedorov effects ?
K. Morawetz
The scattering of wavepackets with arbitrary energy dispersion on surfaces has been analyzed. Expanding up to second order in scattering shifts, it is found that besides the known Goos-Hänchen or Imbert-Fedorov spatial offset, as well as the Wigner delay time, new momentum and frequency shifts appear. Furthermore, the width of the scattered wave packet becomes modified as well, which can lead to a shrinking of pulses by multiple scattering. For a model of dielectric material characterized by a longitudinal and transverse dielectric function the shifts are calculated analytically. From the Goos-Hänchen and Imbert-Fedorov shifts one can access the longitudinal and transversal dielectric function. Perfectly aligned crystal symmetry axes with respect to scattering beam shows no Imbert-Fedorov effect. It is found that the Goos-Hänchen and Imbert-Fedorov effect are absent for homogeneous materials. Oppositely it is found that the Wigner delay time and the shrinking of the temporal pulse width allows to access the dielectric function independent on the beam geometry.
↳ physics.opticscond-mat.mtrl-scinucl-thquant-phRev.Phys.(2025)·0 citations
11
Fully strange tetraquark resonant states as the cousins of $X (6900)$
Yao Ma🇨🇳 · Wei-Lin Wu🇨🇳 · Lu Meng🇩🇪 · Yan-Ke Chen🇨🇳 · Shi-Lin Zhu🇨🇳
We conduct systematic calculations of the S-wave fully strange systems with ``normal" $(J^{P C} = 0^{++}, 1^{+-}, 2^{++})$ and ``exotic" $(J^{P C} = 0^{+-}, 1^{++}, 2^{+-})$ C-parities, which are the strange analogue of the fully charmed tetraquark state $X (6900)$ . Within a constituent quark potential model, we employ the Gaussian expansion method to solve the four-body Schrödinger equation and the complex scaling method to identify resonant states. We obtain a series of resonant states and zero-width states in the mass range of 2.7 to 3.3 GeV, with their widths ranging from less than 1 MeV to about 50 MeV. Their rms radii strongly indicate that they are compact tetraquark states. Among these states, the $T_{4 s, 2^{++}} (2714)$ may be the most likely one to be observed experimentally. We urge the experimental exploration of the $2^{++}$ $ss s ˉ s ˉ$ state around 2.7 GeV in the $ϕϕ$ channel. Since the lowest S-wave $ss s ˉ s ˉ$ state is around 2.7 GeV, the compact P-wave $ss s ˉ s ˉ$ states are expected to be heavier. Hence, $ϕ (2170)$ and $X (2370)$ are unlikely to be compact tetraquark states.
↳ hep-phhep-exhep-latnucl-thPRD(2024)·17 citations
12
Hot and Dense QCD Shear Viscosity at (almost) NLO
Isabella Danhoni🇩🇪 · Guy D. Moore🇩🇪
The next-to-leading order weak-coupling shear viscosity of QCD was computed 6 years ago. However, these results have never been applied at finite baryon chemical potential $μ$ , even though intermediate-energy heavy ion collisions and merging neutron stars may explore the Quark-Gluon Plasma in a regime where baryon chemical potentials are large. Here, we extend the next-to-leading order shear viscosity calculations to finite $μ$ , and we show that, while the convergence of the weak-coupling expansion is questionable for achievable plasmas, it is somewhat better at $μ > T$ than at $μ = 0$ .
↳ hep-phhep-thnucl-thJHEP(2024)·9 citations
13
Investigating the role of nuclear parameters on oscillation modes in hot Neutron Stars
Nilaksha Barman🇮🇳 · Bikram Keshari Pradhan🇮🇳 · Debarati Chatterjee🇮🇳
Recent studies have revealed that certain nuclear parameters are more dominant than others in governing global neutron star properties, such as its structure or oscillation mode characteristics. Although neutron stars can in general assumed to be cold, in astrophysical scenarios such as newly born neutron stars or remnants of binary neutron star mergers, finite temperature effects play a non-negligible role. In this work, we perform a consistent and systematic investigation of the role of nuclear parameters and thermal effects on neutron star properties and fluid oscillation modes within a full general relativistic scheme. We impose constraints on the parameter space of the relativistic mean field model using state-of-the-art information from terrestrial experiments and multi-messenger astrophysical data. We find effective nucleon mass to be the most important nuclear parameter controlling astrophysical observables of hot neutron stars, similar to the cold beta equilibrated matter. However, we conclude that the interplay among saturation properties and astrophysical observables depends not only on the thermal configurations considered but also on the constraints imposed. We also investigated the role of nuclear saturation parameters on some universal relations for hot NSs which are important in gravitational wave asteroseismology. Our investigation confirmed that these relations are mostly insensitive to nuclear saturation properties and mainly affected by variation of charge fraction in the star.
↳ astro-ph.HEgr-qcnucl-thPRD(2025)·10 citations

Affiliations

first authorsco-authorsvia INSPIRE