Nuclear Theory·nucl-th

Thursday·October 9, 2025

9 papers—6 primary·3 cross-listed

01
Proper time expansions and glasma dynamics
Margaret E Carrington🇨🇦 · Bryce T. Friesen🇨🇦 · Doug Pickering🇨🇦 · Shane Sangster🇨🇦 · Kaene Soopramania🇨🇦
The earliest phase of an ultrarelativistic heavy ion collision can be described as a highly populated system of gluons called glasma. The system's dynamics is governed by the classical Yang-Mills equation. Solutions can be found at early times using a proper time expansion. Since the expansion parameter is the time, this method is necessarily limited to the study of early time dynamics. In addition compute time and memory limitations restrict practical calculations to no more than eighth order in the expansion. The result is that the method produces reliable results only for very early times. In this paper we explore several different methods to increase the maximum time that can be reached. We find that, depending slightly on the quantity being calculated, the latest time for which reliable results are obtained can be extended approximately 1.5 times (from $\sim 0.05$ ~fm/ $c$ using previous methods to about $0.08$ ~fm/ $c$ ).
nucl-th0 citations
02
Excitation energy of fission fragments within nuclear time-dependent density functional theory
Antonio Bjelčić🇺🇸 · Nicolas Schunck🇺🇸 · Marc Verriere🇺🇸
The number and properties of the neutrons and photons emitted in nuclear fission are directly related to the excitation energy of the fission fragments when they are formed at scission. Though not observable experimentally because of the extremely short time scales, the excitation energy of fission fragments can be predicted by microscopic theory based on time-dependent density functional theory (TDDFT). Initial results on the value of the total kinetic energy of fission reactions were very promising, but could not probe all possible fragmentations. In this work, we perform large-scale TDDFT calculations in $^{240}$ Pu enabled by the development of a new TDDFT solver. We obtain TDDFT trajectories covering nearly all possible fragmentations. We find that the total kinetic energy is close to experimental values only for the most likely fission while it is severely underestimated at both small and large asymmetries. This conclusion seems rather independent of the parameterization of the energy functional, both in its particle-hole and particle-particle channels.
nucl-thPRC(2026)·7 citations
03
A Data-Guided Coalescence Model for Light Nuclei and Hypernuclei Production in Relativistic Heavy-Ion Collisions at $s_{NN} = 3$ --200 GeV
Yue Hang Leung🇩🇪 · Yingjie Zhou🇩🇪 · Norbert Herrmann🇩🇪
The production of light hypernuclei in relativistic heavy-ion collisions provides a unique opportunity to probe hyperon--nucleon interactions and possible three-body forces, which are central to the resolution of the hyperon puzzle in neutron star matter. In this work, we develop a data-guided coalescence framework in which the source size is extracted from proton and deuteron yields and used, together with measured proton and $Λ$ spectra, to predict the production of $A = 3$ nuclei $(t,^{3} He)$ and hypernuclei $(_{Λ}^{3} H)$ in $s_{NN} = 3$ --200~GeV Au+Au collisions. For tritons, calculations with a Gaussian wave function reproduce experimental spectra and yield ratios across this energy range. For the hypertriton, the model predictions are highly sensitive to the assumed wave function. This sensitivity is strongest at low collision energies and in low-multiplicity environments, implying that such conditions are particularly valuable for probing hypernuclear structure.
nucl-thPRC(2026)·5 citations
04
Scattering of charged particles within Efros method utilizing oscillator series expansion of wave functions
Ustin M. Yanikov · Vasily A. Kulikov · Andrey M. Shirokov
We apply the version of the Efros method utilizing oscillator expansion of wave functions to the Coulomb scattering problem using our recent developments of the HORSE formalism. The approach yields accurate phase shifts and cross sections with significantly reduced computational cost compared to the full HORSE method, while maintaining agreement with exact solutions. These results demonstrate the efficiency of the Efros method and its prospect for applications in ab initio nuclear reaction calculations.
nucl-thIJMPE(2026)·0 citations
05
Transport-based initial conditions for heavy-ion collisions at finite densities
H. Roch🇺🇸 · G. Pihan🇺🇸 · A. Monnai🇯🇵 · S. Ryu🇺🇸 · N. Senthilkumar🇺🇸 · J. Staudenmaier🇩🇪 · H. Elfner🇩🇪 · B. Schenke🇺🇸 · J. H. Putschke🇺🇸 · C. Shen🇺🇸 · S. A. Bass🇺🇸 · M. Chartier🇬🇧 and 44 other authors
We employ the SMASH transport model to provide event-by-event initial conditions for the energy-momentum tensor and conserved charge currents in hydrodynamic simulations of relativistic heavy-ion collisions. We study the fluctuations and dynamical evolution of three conserved charge currents (net baryon, net electric charges, and net strangeness) with a 4D lattice-QCD-based equation of state, NEOS-4D, in the hydrodynamic phase. Out-of-equilibrium corrections at the particlization are generalized to finite densities to ensure the conservation of energy, momentum, and the three types of charges. These theoretical developments are integrated within the X-SCAPE code as a unified framework for studying the nuclear matter properties in the Beam Energy Scan program.
nucl-thhep-phPRC(2026)·5 citations
06
A method to obtain bounds on the equation of state of cold nuclear matter from imaginary chemical potentials
Thomas D. Cohen🇺🇸
The sign problem in numerical calculations of the QCD Euclidean space path integral of QCD with a chemical potential vanishes if the chemical potential is imaginary. Moreover, calculations of the partition function with imaginary chemical potentials are equivalent to calculations with Lagrange multipliers enforcing the current density. At zero temperature, Lorentz boosts allow one to deduce properties of systems with both number density and current density from properties of systems with a current density alone; this allows both upper and lower bounds to be determined for the equation of state (EOS) in the form of energy density as a function of number density.
nucl-thhep-latPRL(2026)·3 citations
07
Impact of relativistic corrections to high-pT prompt-psi(2S) production at hadron colliders
Valerio Bertone🇫🇷 · Jean-Philippe Lansberg🇫🇷 · Kate Lynch🇫🇷
We study relativistic corrections to prompt psi(2S) production at high pT in hadron colliders. Our calculation employs leading-power factorization with Fragmentation Functions (FFs) computed in nonrelativistic QCD and evolved to next-to-leading-logarithmic accuracy. Relativistic corrections increase the cross section significantly for the gluon channel, but moderately for charm. We perform a full analysis of uncertainties. We observe a good agreement with both ATLAS and CMS cross sections without the need of higher-order color-octet contributions. The polar anisotropy is found to be close to CMS data, partly due to charm fragmentation.
↳ hep-phhep-exhep-thnucl-th4 citations
08
Classification of $g$ -modes for neutron stars with a strong transition: Novel universal relation including slow stable hybrid stars
M. C. Rodriguez🇨🇱 · José C. Jiménez🇧🇷 · Ignacio F. Ranea-Sandoval🇨🇱
We investigate the behavior of the non-radial gravity-pulsation discontinuity $g$ -mode in neutron stars with a strong first-order phase transition which give rise to hybrid-star configurations. These modes are of utmost relevance since they can be potentially excited in isolated as well as binary neutron star systems in the inspiral phase, thus allowing us to indirectly detect the presence of a deconfinement transition. In order to do this, we consider four categories of hybrid stars that present distinctive features in their equations of state. We employ the constant speed of sound parametrization, which accounts for a sharp phase transition between confined hadronic matter and deconfined quark matter. Then, working within the relativistic Cowling approximation to obtain the frequencies of non-radial oscillations, we find that, depending on the hybrid star category, the relations between discontinuity $g$ -mode frequencies and masses as well as tidal deformabilities display a highly distinct behavior across the diverse hybrid star categories that appear in the slow hadron-quark conversion regime. This distinct phenomenology provides smoking-gun evidence to clearly distinguish and further classify hybrid stars with a strong transition from purely hadronic stars using upcoming gravitational-wave data. In addition, we present for each of the categories studied the relation between the $g$ -mode frequency and the normalized energy density jump. Finally, we present a novel universal relation for the discontinuity $g$ -mode able to encompass the four categories including long branches of slow stable hybrid stars and address its asteroseismological capability.
↳ hep-phastro-ph.HEgr-qcnucl-thPRD(2026)·4 citations
09
Dissecting the moat regime at low energies I: Renormalization and the phase structure
Fabian Rennecke🇩🇪 · Shi Yin🇩🇪
Dense QCD matter can feature a moat regime, where the static energy of mesons is minimal at nonzero momentum. Valuable insights into this regime can be gained using low-energy models. This, however, requires a careful assessment of model artifacts. We therefore study the effects of renormalization and in-medium modifications of quark-meson interaction on the moat regime. To capture the main effects, we use a two-flavor quark-meson model at finite temperature and baryon density in the random phase approximation. We put forward a convenient renormalization scheme to account for the nontrivial momentum dependence of meson self-energies and discuss the role of renormalization conditions for renormalization group consistent results on the moat regime. In addition, we demonstrate and that its extent in the phase diagram critically depends on the interaction of quarks and mesons.
↳ hep-phhep-thnucl-thPRD(2026)·5 citations

Affiliations

first authorsco-authorsvia INSPIRE