Nuclear Theory·nucl-th

Friday·January 9, 2026

9 papers—1 primary·8 cross-listed

02
Characterizing radial flow fluctuations in relativistic heavy-ion collisions at top RHIC and LHC energies
Lipei Du🇺🇸
We present a systematic investigation of the transverse-momentum differential radial flow fluctuations observable $v_{0} (p_{T})$ in relativistic heavy-ion collisions at top RHIC ( $s_{NN} = 200$ GeV) and LHC ( $s_{NN} = 2.76$ and 5.02 TeV) energies. Using a multistage hydrodynamic model, we assess the sensitivity of $v_{0} (p_{T})$ to a wide range of physical effects, including bulk and shear viscosities, off-equilibrium corrections at particlization, the presence of a hadronic afterburner, and the nucleon size in the initial conditions. By employing complementary rescaling strategies, we demonstrate how different physical effects leave distinct imprints on the shape of $v_{0} (p_{T})$ . A combined double-rescaling of $v_{0} (p_{T}) / v_{0}$ versus $p_{T} / ⟨ p_{T} ⟩$ reveals a universality across a wide range of energies and model assumptions in the low- $p_{T}$ regime, a robust signature of collective behavior. This allows us to disentangle the universal dynamics of the bulk medium from model-specific features that emerge at higher $p_{T}$ . Our results establish $v_{0} (p_{T})$ as a powerful and complementary observable for constraining QGP transport properties and initial-state granularity, offering a unique probe of the created QCD medium.
↳ nucl-exhep-phnucl-thPRC(2026)·16 citations
03
Color-Singlet and Color-Octet Quark Matters
Cheuk-Yin Wong🇺🇸
Quarks and antiquarks carry color and electric charges and belong to the color-triplet $3$ group and the color-antitriplet $3 ˉ$ group respectively. The product groups of $3$ and $3 ˉ$ consist of the color-singlet $1$ and the color-octet $8$ subgroups. Therefore, quarks and antiquarks combine to form color-singlet $[q q ˉ]^{1}$ quark matter and color-octet $[q q ˉ]^{8}$ quark matter. The color-octet quark matter corresponds to the $q q ˉ$ quark matter as envisaged in the realm of present knowledge but the color-singlet quark matter is as yet unexplored and now submitted for exploration. The color-singlet quark matter with two flavors can be separated into charged and neutral color-singlet quark matters. In the neutral color-singlet quark matter, the quark and the antiquark interacting only in the QED interaction may form stable and confined colorless QED mesons non-perturbatively at about 17 MeV and 38 MeV (PRC81,064903(2010) and JHEP(2020(8),165). It is proposed that the possible existence of the QED mesons may be a signature of the neutral color-singlet quark matter at $T = 0$ . The observations of the anomalous soft photons at CERN, and the anomalous bosons with mass about 17 MeV at ATOMKI, DUBNA, and HUS, and mass about 38 MeV at DUBNA hold promising experimental evidence for the existence of such QED mesons, pending further confirmations.
↳ hep-phastro-ph.HEhep-thnucl-thUkr.J.Phys.(2026)·0 citations
04
A New Bayesian Framework with Natural Priors to Constrain the Neutron Star Equation of State
Boyang Sun🇺🇸 · Tianqi Zhao🇺🇸 · James M. Lattimer🇺🇸
We propose a new Bayesian framework to infer the neutron star equation of state (EOS) from mass and radius observations and neutron matter theory by defining priors that directly parameterize mass-radius space instead of pressure-energy density space. We use direct and accurate inversion approximations to map mass-radius relations to the underlying EOS. We systematically compare its EOS inferences with those inferred from traditional EOS parameterizations, taking care to quantify the systematic prior uncertainties of both. Our results show that prior uncertainties should be included in all Bayesian approaches. The more natural alternative framework provides broader coverage of the physically allowed mass-radius space, especially small radius configurations, and yields enhanced computational efficiency and substantially reduced dependence on prior choices. Our results demonstrate that direct parameterization in observed space offers a robust and efficient alternative to traditional methods.
↳ astro-ph.HEastro-ph.SRnucl-th3 citations
05
Experimental study of $^{53}$ Cr via the $(d, p γ)$ reaction
M. Spieker🇺🇸 · L.A. Riley🇺🇸 · M. Heinze🇺🇸 · A.L. Conley🇺🇸 · B. Kelly🇺🇸 · P.D. Cottle🇺🇸 · R. Aggarwal🇺🇸 · S. Ajayi🇺🇸 · L.T. Baby🇺🇸 · S. Baker🇺🇸 · I. Conroy🇺🇸 · I.B. D'Amato🇺🇸 and 15 other authors
Excited states in $^{53}$ Cr were studied via the $^{52}$ Cr $(d, p γ)$ reaction up to the neutron-separation threshold. Proton- $γ$ angular correlations and $γ$ decay branching ratios were measured in particle- $γ$ coincidences between the Super-Enge Split-Pole Spectrograph (SE-SPS) and CeBr $_{3}$ Array (CeBrA) demonstrator of the John D. Fox Accelerator Laboratory at Florida State University. Previous spin-parity assignments from a $(d, p)$ singles experiment at the SE-SPS are supported and $γ$ -ray transitions in $^{53}$ Cr reported. We firmly assign higher-lying excited states to $^{53}$ Cr because overlapping excited states and contaminants could be identified better due to the complementary $γ$ -decay information. We also correct some of the previously reported excitation energies and present a reanalysis of previously measured $^{52}$ Cr $(d, p)^{53}$ {Cr} angular distributions guided by the complementary $γ$ -ray information. Based on this reanalysis, the fragmentation of the neutron $2 p_{3/2}$ , $2 p_{1/2}$ , $1 f_{5/2}$ , $1 g_{9/2}$ , and $2 d_{5/2}$ single-particle strengths is reassessed for $^{53}$ Cr. A comparison to the corresponding strengths in $^{55}$ Fe is presented.
↳ nucl-exnucl-thPRC(2025)·0 citations
06
Propagating Uncertainties from Nuclear Physics to Gamma-rays in Core Collapse Supernovae
Chris L Fryer🇺🇸 · Hendrik Schatz🇺🇸 · Samuel Jones🇺🇸 · Atul Kedia🇺🇸 · Richard Longland🇺🇸 · Fabio Magistrelli🇩🇪 · Gerard Navo🇪🇸 · Joshua Issa🇨🇦 · Patrick A Young🇺🇸 · Alison M. Laird🇬🇧 · Jeffery C. Blackmon🇺🇸 · Almudena Arcones🇩🇪 and 9 other authors
Nuclear yields are powerful probes of supernova explosions, their engines and their progenitors. In addition, as we improve our understanding of these explosions, we can use nuclear yields to probe dense matter and neutrino physics, both of which play a critical role in the central supernova engine. Especially with upcoming gamma-ray detectors that can directly detect radioactive isotopes out to increasing distances from gamma-rays emitted during their decay, nuclear yields have the potential to provide some of the most direct probes of supernova engines and stellar burning. To utilize these probes, we must understand and limit the uncertainties in their production. Uncertainties in the nuclear physics can be minimized by combining both laboratory experiments and nuclear theory. Similarly, astrophysical uncertainties caused by simplified explosion trajectories can be minimized by higher-fidelity stellar-evolution and supernova-engine models. This paper reviews the physics and astrophysics uncertainties in modeling nucleosynthetic yields, identifying the key areas of study needed to maximize the potential of supernova yields as probes of astrophysical transients and dense-matter physics.
↳ astro-ph.HEnucl-exnucl-th1 citation
07
Scattering of a weakly bound dimer from a hard wall in one dimension
Xican Zhang🇨🇳 · Shina Tan🇨🇳
We consider a dimer formed by two particles with an attractive contact interaction in one dimension, colliding with a hard wall. We compute the scattering phase shifts and the reflection coefficients for various collision energies and various mass ratios of the two particles. For low-energy collisions (with dimer kinetic energies much smaller than the binding energy) our results are consistent with those of D. Lee and M. Pine, The European Physical Journal A 47, 41 (2011). For mass ratios much greater than 1 we use the Born-Oppenheimer approximation to show that the scattering length and the effective range of the dimer-wall collision both depend logarithmically on the mass ratio. For collision energies much greater than the binding energy, the dissociation probability is inversely proportional to the square of the incident momentum of the dimer and we find the constant of proportionality analytically, and we use a semiclassical analysis to approximately derive the ``angular distribution" of the dissociated pair, where the ``angle" $θ$ depends on the ratio of the velocities of the two outgoing unbound particles.
↳ cond-mat.quant-gasnucl-thPRA(2026)·0 citations
08
QCD Crossover at Low Temperatures from Lee-Yang Edge Singularity
D. A. Clarke🇩🇪 · H.-T. Ding🇨🇳 · J.-B. Gu🇨🇳 · S.-T. Li🇨🇳 · Swagato Mukherjee🇺🇸 · P. Petreczky🇺🇸 · C. Schmidt🇩🇪 · H.-T. Shu🇨🇳 · K.-F. Ye🇨🇳
We provide the first lattice-QCD estimate of the crossover line down to $T ≃ 108$ ~MeV. We introduce a new method that combines the Lee-Yang edge in the complex plane of baryon chemical potential $μ_{B}$ with universal chiral scaling to determine the $μ_{B}$ dependence of the QCD chiral critical and pseudo-critical temperatures. By performing $(2 + 1)$ -flavor lattice QCD simulations at $T ≃ 108$ ~MeV and purely imaginary $μ_{B}$ with a single lattice spacing and two volumes, we compute $μ_{B}$ -dependent baryon-number susceptibilities and extract the location of the Lee-Yang edge. Together with universal scaling near the QCD chiral transition, it constrains the mapping function between ${T, μ_{B}}$ and the scaling variable (\textit{i.e.}\ the argument of the universal scaling functions). This mapping function then yields the $μ_{B}$ dependence of the critical and pseudo-critical temperatures for $T ≳ 108$ ~MeV. While our calculation is performed only at a single value of low temperature without explicit input from small- $μ_{B}$ expansion, the resulting $μ_{B}$ dependence of the pseudo-critical temperature is consistent with established lattice-QCD determinations at small $μ_{B}$ and compatible with chemical freeze-out parameters of heavy-ion collisions down to low temperatures, demonstrating the validity and robustness of the method. Application of this method can be systematically extended to additional temperatures and finer discretizations, opening a pathway to charting the QCD phase diagram in the low- $T$ , high- $μ_{B}$ regime.
↳ hep-lathep-phnucl-exnucl-th1 citation
09
Effective Range Expansion with the Left-Hand Cut: Higher Order Improvements
Wen-Jia Wang🇨🇳 · Bing Wu🇨🇳 · Meng-Lin Du🇨🇳 · Feng-Kun Guo🇨🇳
A model-independent parameterization of the low-energy scattering amplitude that incorporates the left-hand cut from one-particle exchange, an extension of the conventional effective-range expansion (ERE), was recently proposed and successfully applied to the low-energy $D D^{*}$ system [Phys. Rev. Lett. 135, 011903 (2025)]. While the original formulation is based on a nonrelativistic approximation and is thus limited to a [1,1] approximant for self-consistency, we extend the framework by explicitly including the higher-order terms up to $O (k^{6})$ . We systematically investigate the reliability and robustness of the generalized ERE by incorporating relativistic kinematic effects. In addition, we develop a relativistic version of the ERE that accounts for lhc contributions. These results affirm the generalized ERE as a robust and systematically improvable framework for near-threshold scattering processes, providing both analytical and numerical reliability for applications in two-body scattering problems with a particle exchange.
↳ hep-phnucl-thPRD(2026)·2 citations

Affiliations

first authorsco-authorsvia INSPIRE