Nuclear Theory·nucl-th

Fri·Sep 25, 2026Friday·September 25, 2026

15 papers—8 primary·7 cross-listed

01
Microscopic study of low-lying energy levels and electromagnetic properties in even-even $^{168 - 178}$ Yb nuclei
Carlos E. Vargas · Víctor Velázquez-Aguilar
Employing methods based on symmetries for the theoretical description of rare-earth nuclei offers many advantages. Among these, the pseudo-SU(3) shell model has proved to be a very useful method to describe characteristics of these systems and to understand various properties. A theoretical description of the low-lying energy spectrum and electromagnetic properties of isotopes $^{168 - 178}$ Yb is carried out for the first time with this model, comparing theoretical results with the experimental values, where possible. The Hamiltonian includes the $Q \cdot Q$ term which preserves the symmetry, as well as the breaking symmetry of Nilsson and pairing terms. Additionally, three rotor type terms are included that allow us to make a subtle adjustment of the spectrum. The results show that the energy spectrum, the B(E2) transitions, the g-factors and the electric quadrupole moments can be described adequately with the model. Although the model is a powerful tool in the description of low-lying properties of normal parity in heavy deformed nuclei, it finds its strongest limitation in the abnormal parity sector, which has been left out of the description.
nucl-thEur. Phys. J. A (2024) 60:138
02
Electromagnetic properties in $^{160 - 170}$ Dy nuclei: A microscopic description by the pseudo-SU(3) shell model
Carlos E. Vargas · Víctor Velázquez · Sergio Lerma-Hernández · Norma Bagatella-Flores
The large collectivity observed in the rare earth region of the nuclear landscape is well known. The microscopic studies are difficult to perform in this region due to the enormous size of the valence spaces, a problem that can be avoided by means of the use of symmetry based models. Here we present calculations for electromagnetic properties of $^{160 - 170}$ Dy nuclei within the pseudo-SU(3) scheme. The model Hamiltonian includes the preserving symmetry $Q \cdot Q$ term and the symmetry-breaking Nilsson and pairing terms, systematically parametrized for all members of the chain. The model is used to calculate B(E2) and B(M1) inter-band transition strengths between the ground state, $γ$ and $β$ -bands. In addition, we present results for quadrupole moments and $g$ factors in these rotational bands. The results show that the pseudo-SU(3) shell model is a powerful microscopic theory for a description of electromagnetic properties of states in the normal parity sector in heavy deformed nuclei.
nucl-thEur. Phys. J. A (2017) 53: 73
03
Constraining Energy Density Functionals via Bayesian Analysis of Nuclear Densities
Chengpeng Yu · Kenichi Yoshida
In nuclear many-body physics, energy density functional (EDF) theory is one of the most powerful approaches for describing finite nuclei and nuclear matter. However, its predictive capability depends on calibrating model parameters to experimental and observational data. In this work, we investigate an alternative approach: Constraining the parameters with the continuous density profiles of finite nuclei obtained from ab initio calculations. We apply Bayesian analysis to infer the parameters of Skyrme EDF from the density profiles and binding energies of 16O, 40Ca, and 48Ca. We show that the data effectively constrain the parameters associated with the properties of uniform nuclear matter, whereas those governing non-uniform nuclear matter remain partially constrained and require additional input. Furthermore, using the inferred parameter distributions, we successfully predict the density profiles and binding energy of 208Pb, which is excluded from the training data. This demonstrates the predictive capability of the framework. In conclusion, these results establish Bayesian analysis of density profiles as a promising route for incorporating accurate ab initio results of light nuclei into EDF development and strengthening the connection between both approaches.
nucl-th
04
Measuring short-range correlations using relativistic heavy-ion collisions
Lu-Meng Liu · Jun Xu · Xu-Guang Huang
We propose a novel method to measure the strength and isospin dependence of short-range correlations (SRCs) in nuclei with their collisions at relativistic energies. Since nucleons in the high-momentum tail (HMT) induced by SRCs have large transverse velocities, we find that measuring the yield ratio of free spectator neutrons at large to small transverse distances detected by Zero-Degree Calorimeter (ZDC) array may probe the fraction of nucleons in the HMT. In addition, measuring the yield ratio of ZDC neutrons in central $^{96}$ Zr+ $^{96}$ Zr to $^{96}$ Ru+ $^{96}$ Ru collisions at large transverse distances may probe the isospin dependence of the HMT and SRCs. Compared to traditional scattering experiments, our study illustrates that relativistic heavy-ion collisions may serve as an alternative way of measuring SRCs in colliding nuclei with less final-state interactions.
nucl-thhep-exnucl-ex
05
Exploring the Parameter Space of pvCD-Bonn Potentials under Constraints from Nuclear Saturation Properties
Ke Nan · Chencan Wang · Jinniu Hu · Ying Zhang · Hong Shen
We explore the parameter space of the pvCD-Bonn B potential within the relativistic Brueckner--Hartree--Fock framework under the constraints from the empirical saturation properties of symmetric nuclear matter. We first examine the effects of the scalar-meson and pion coupling constants. Changing the $σ$ -meson couplings in the $^{1} S_{0}$ and $^{3} S_{1}$ -- $^{3} D_{1}$ channels alone cannot reproduce the empirical saturation density and binding energy at the same time, whereas increasing $g_{π}$ moves the saturation point toward the empirical region. However, changing $g_{π}$ alone also affects the deuteron properties and tensor-sensitive observables. We therefore extend the parameter search by varying the $ρ$ -meson tensor coupling $f_{ρ} / g_{ρ}$ and readjusting the effective $σ$ -meson couplings in the $^{1} S_{0}$ and $^{3} P_{0}$ channels. Four representative parameter sets with $g_{π}^{2} /4 π = 14.7$ --15.0 give deuteron properties close to the experimental values and maintain a reasonable description of the main neutron--proton phase shifts and differential cross sections at $E_{lab} = 50$ and 212 MeV. Their saturation densities lie in the range $0.159$ -- $0.161 fm^{- 3}$ , with saturation energies between $- 15.00$ and $- 15.38 MeV$ . For the interactions obtained by varying $g_{π}$ , the neutron-star mass--radius relations show only a weak dependence on the pion coupling, with maximum masses of about $2.24$ -- $2.28 M_{⊙}$ and radii of about $12.3$ -- $12.6 km$ at $1.4 M_{⊙}$ . These results show that including the $ρ$ -meson tensor coupling and partial-wave-dependent $σ$ -meson couplings provides a better balance between free-space two-nucleon observables and nuclear-matter saturation properties than varying the pion coupling alone.
nucl-th
06
Sensitivity of quasifission dynamics to the nuclear symmetry energy in $^{48}$ Ca+ $^{249}$ Cf
C. Ross · R. Gumbel · K. Godbey · A.S. Umar
We present a systematic study of the sensitivity of quasifission dynamics to the nuclear symmetry energy in the $^{48}$ Ca~+~ $^{249}$ Cf system, the reaction used for the synthesis of oganesson ( $Z = 118$ ), spanning the full range of target orientations and angular momenta. Employing time-dependent Hartree-Fock (TDHF) calculations with four Skyrme parameterizations from the SV family that systematically vary the symmetry energy at saturation ( $a_{sym} = 28$ -- $34$ ~MeV), we perform over 500 TDHF trajectories spanning angular momenta $L = 0$ -- $100ℏ$ and twelve orientations of the prolate-deformed $^{249}$ Cf target ( $β = 0^{\circ}$ -- $16 5^{\circ}$ in $1 5^{\circ}$ steps). Shell effects in the quasifission fragments are dominated by a deformed--deformed channel: the light fragment clusters near the prolate-deformed $Z \approx 40$ , $N \approx 58$ shell region (Zr/Sr), and the complementary heavy fragment populates the shape-coexistence region near $Z \approx 78$ , $N \approx 121$ (Os/Pt). This channel accounts for $34$ -- $48%$ of quasifission events and is geometrically incompatible with the spherical $Z = 82$ , $N = 126$ closures, which are populated only at shorter contact times. The balance between the deformed and near-spherical channels depends on the symmetry energy parameterization. These results demonstrate that quasifission observables in superheavy element formation reactions carry quantifiable sensitivity to the isovector sector of the nuclear energy density functional.
nucl-th
07
Rapid Uncertainty Quantification on a Latent Field using Fisher Information
Karl Daningburg · A. E. Lovell · Arvind T. Mohan · R. O'Shaughnessy
Many inverse problems in physics infer an unobserved field from measurements connected to it through a governing equation. We combine Fisher information with a differentiable solver to quantify uncertainty in both the inferred field and its predicted observables, using a local Gaussian approximation without sampling the full parameter posterior. Applied to nuclear optical potentials, the method distinguishes features constrained by scattering measurements from those whose uncertainty remains set by the prior. Our flexible model improves agreement with held-out cross sections and achieves nearly nominal coverage with narrower predictive intervals than an established Bayesian optical model.
nucl-thphysics.comp-phphysics.data-an
08
Extending multi-messenger constraints on neutron star matter through the inclusion of direct Urca cooling
M. Dio Danarianto · Guilherme Grams · Thibeau Wouters · Tim Dietrich
The properties and behavior of strongly interacting matter at extreme densities can not only be determined through terrestrial experiments or through theoretical considerations, but also astrophysical observations of neutron stars (NSs) and binary neutron star systems become increasingly important to obtain complementary information. In light of these findings, we perform a Bayesian study inferring the NS equation of state (EoS) by incorporating constraints from the direct Urca (dUrca) process, thereby including information on matter composition in addition to traditionally used macroscopic observables. We implement a self-consistent treatment of $β$ -equilibrium and charge neutrality in the \textsc{jester} framework, including the calculation of the proton fraction and the onset of nucleonic dUrca in the presence of electrons and muons. We combine constraints from chiral effective field theory, astrophysical measurements of NS masses, radii, and tidal deformabilities, and observations of rapidly and slowly cooling neutron stars. The dUrca constraint seems to be in favor of stiffer EoSs, but --at the current stage-- has only a minor impact on macroscopic NS properties once we include other nuclear and astrophysical constraints. In contrast, the dUrca information provides a constraint on the composition of canonical-mass NSs favoring a higher proton fraction inside the star, illustrating the complementary information carried by cooling observations. Our results demonstrate the potential of incorporating composition-sensitive observables into multimessenger inference and provide a step toward a more comprehensive treatment of dUrca constraints with microscopically motivated EoS models.
nucl-thastro-ph.HE
09
Simulating the emission source function in very peripheral relativistic heavy-ion collisions
Angel Reina Ramírez · Volodymyr Magas · Juan M. Torres-Rincon🇪🇸
We present a microscopic femtoscopic investigation of the space-time emission source in low-multiplicity (80--90\% centrality) $Pb - Pb$ collisions at $s_{N N} = 5.02 TeV$ , using a hybrid transport framework coupling SMASH initial conditions, 3+1D viscous hydrodynamics (vHLLE), and a SMASH hadronic cascade afterburner. Access to the full space-time evolution of the produced particles allows for the direct reconstruction of emission source functions in both the Longitudinally Comoving System and the Pair Rest Frame. We study identical pairs of mesons ( $π π$ , $K K$ ) and baryons ( $pp$ ), as well as cross-species combinations, while explicitly isolating the contributions from primordial particles, hadronic rescattering, and long-lived resonance decays. Our analysis shows that simple Gaussian fits are inadequate for precision source analyses, whereas a combined Gaussian plus exponential parametrization better captures the compact core and the extended tail. Finally, the extracted Gaussian core radii, $R_{core}$ , for our very peripheral collisions demonstrate an approximate $m_{T}$ -scaling behavior rather similar to the one observed in pp reactions.
↳ hep-phnucl-th0 citations
10
Finite-Temperature Axion-Admixed Neutron Stars in a Quarkyonic Crossover Framework
S. K. Patra · D. Dey · Jeet Amrit Pattnaik · R. N. Panda
We analyze the effect of axion contribution on the mass, radius and dimensionless deformability of a neutron star (NS) at finite temperature. Although the cooling of an NS is mainly due to the emission of neutrinos, additional cooling cannot be ruled out due to the emission of axions. The existence of an axion is needed for addressing the strong CP problem within the standard model. The Peccei-Quinn (PQ) symmetry breaking mechanism generates axions. They are pseudo-Nambu-Goldstone bosons. Their mass is extremely small but non-zero. This naturally resolves the fine-tuning problem of the strong CP-violating parameter $θ ≲ 1 0^{- 10}$ . We propose that a finite temperature NS feature a quark core surrounded by a baryonic medium admixed with the axions, which are pseudo scalar Goldstone bosons and are considered as strong candidates for the dark matter (DM). Unlike the original quarkyonic model, we formulate a quarkyonic-inspired smooth crossover equation of state (EoS) at finite temperatures. This smooth crossover avoids thermodynamic instabilities found in sharp first-order constructions. We add the axionic EoS to the finite temperature quarkyonic one and solve the Tolman-Oppenheimer-Volkoff equations to estimate the properties of the NS both with and without taking the axion into account at different temperatures. We find that the production of axions is maximum within a radius of $5 - 11$ km in the star's interior; however, the impact on the mass is significant, i.e., $\sim 60%$ of axion mass concentrated in the central region of the star. We also find that the effect of temperature on the mass of NS is marginal unlike the radius. In general, the influence of axions is significant for the observational properties of NS. These results highlight the pivotal role of axion physics in neutron star phenomenology.
↳ hep-phastro-ph.HEastro-ph.SRnucl-th
11
Stability of hybrid stars via catastrophe theory
Eduardo S. Fraga · Sergio E. Jorás
We discuss the possible topologies of the mass-radius relation for hybrid stars in light of catastrophe theory. We show that different branches of compact stars emerge or disappear depending on the bifurcation structure of the underlying catastrophe potential function, the mathematical analog of an effective potential. For that we assume a single first-order phase transition between nuclear and quark matter. After a warm up with incompressible fluids, we present a qualitative discussion explaining the (dis)appearance of (un)stable branches for hybrid stars as the control parameters change.
↳ astro-ph.HEhep-phnucl-th
12
Fundamental Physics at the Frontier of Noisy Quantum Computation
Nikita A. Zemlevskiy
Quantum computing offers a new, orthogonal direction for investigating fundamental physics, extending beyond classical numerical methods and conventional observables. Realizing this potential requires directly confronting the noise limiting currently available quantum computers. Progress rests on advancing algorithms, interpreting their results, and managing their errors together. This thesis presents several advancements in the use of quantum simulation and quantum information to probe fundamental physics. The first is in the use of quantum computers to simulate collisions in quantum field theories. Central to these simulations are new wavepacket preparation, time evolution, and error mitigation techniques, which allow for simulations with some of the largest effective circuit volumes to date. These methods enable the first quantum simulation providing numerical evidence for inelastic particle production, a key process in fundamental physics. The second advancement centers on the role quantum-information-theoretic quantities play in physical processes. Beyond mere correlations with the physics of the process, entanglement and magic are shown to probe the interactions present in scattering and hadronization dynamics. A precision study requires a complete quantification of algorithmic and hardware uncertainties, an outstanding goal as quantum simulations mature. The third advancement in this thesis addresses error management. A framework minimizing the effect of algorithmic errors in analog quantum simulations is presented. In a step toward fault tolerance, error detection in encoded quantum simulations is shown to improve estimation of local observables relative to unencoded runs. Together, the developments in this thesis mark practical progress toward fault-tolerant quantum simulations of fundamental physics capable of scientific discovery.
↳ quant-phhep-lathep-phnucl-th
13
Multi-messenger and multi-band signal from first-order phase transitions in proto-neutron stars
Christian Ecker · Mauro Giliberti · Luciano Rezzolla
A first-order phase transition (PT) alters a compact star on two scales: globally, via growth of a quark-matter core, and microscopically, via collision of quark bubbles, driving a simultaneous gravitational-wave (GW) emission in the kHz and MHz bands. Using a constrained ensemble of model-agnostic equations of state, we follow the accretion-driven evolution of proto-neutron stars through the PT and compute the resulting multi-band GW signal. The correlations found between the kHz emission and the MHz burst could help constrain nuclear matter and the physics of the PT. A delayed neutrino burst should accompany the signal, with the delay set by the details of the PT, thus providing a prime multi-messenger source.
↳ gr-qcastro-ph.HEhep-phnucl-th
14
Quantum Phase Transitions in Nuclei and the Origin of Rhodium
P. Agarwal · H. Schatz · A. Francis · F. Montes · B. Pol · L. Roberts
The astrophysical rapid neutron capture process (r-process) is a major nucleosynthesis process responsible for the production of elements heavier than copper. Prominent features in the observationally inferred r-process abundance distributions provide critical clues for astrophysical conditions and possible r-process sites. The lack of clear features for the r-process elements lighter than tellurium has led to a broad range of proposed possible scenarios and alternative processes that may produce these elements. Here we show that the enhancement found in the solar system of rhodium and ruthenium isotopes compared to neighboring isotopes can serve as such a feature. The enhancement can be traced back to sudden changes in shape of unstable rare isotopes in the path of the light element r-process. Such shape changes have been described as quantum phase transitions. This finding points to r-process scenarios with relatively high neutron densities and temperatures for the origin of rhodium and ruthenium in the solar system. Rhodium and ruthenium abundances observed in r-process enhanced stars can now be used as diagnostics for the r-process conditions that produce these lighter r-process elements. Observational data for these elements indicate that different types of r-processes may have operated in the early Galaxy, and that the conditions do not necessarily align with the weak and main r-process classifications used in the past.
↳ astro-ph.SRnucl-th
15
Centrality-dependent nuclear modification from hard-soft correlations in the glasma
Coleridge Faraday · W. A. Horowitz · Björn Schenke
We present first predictions from the saturation-physics-based framework IP-Glasma for the nuclear modification factor $R_{A B}$ as a function of centrality in $p$ + O, $p$ + Pb, O + O, and Pb + Pb collisions due only to initial-state effects. The same framework is responsible for both soft ( $p_{T} ≲ 3 GeV$ ) and semi-hard ( $5 GeV ≲ p_{T} ≲ 20 GeV$ ) particle production, enabling the study of initial-state correlations between bulk and intermediate- $p_{T}$ particle production from a first-principles framework. We show that, tuned only to HERA data, IP-Glasma accurately predicts the self-normalized multiplicity distributions in $p$ + O, $p$ + Pb, O + O, and Pb + Pb collisions; the minimum-bias nuclear modification factor in $p$ + O and $p$ + Pb collisions; the centrality-cut nuclear modification factor in $p$ + Pb collisions; and the anomalous suppression of $R_{AA}$ observed in very peripheral Pb + Pb collisions. We find that IP-Glasma predicts significantly less suppression than is measured in both $s_{N N} = 5.36 TeV$ O + O and $s_{N N} = 5.02 TeV$ Pb + Pb collisions at the Large Hadron Collider, in qualitative agreement with the scenario in which $R_{AA} < 1$ is due to final-state energy loss. We show that the inelastic nucleon-nucleon cross section ( $σ_{inel}^{N N}$ ) produced by IP-Glasma is extremely sensitive to the area of the subnucleonic hotspots; the same values of the hotspot area that reproduce the measured $σ_{inel}^{N N}$ also reproduce minimum-bias $R_{p A}$ . Finally, we show that the hard-soft correlations in IP-Glasma arise from event-by-event fluctuations in the color fields, which simultaneously drive enhanced production of both soft and hard particles.
↳ hep-phnucl-th