Nuclear Theory·nucl-th

Friday·January 30, 2026

9 papers—5 primary·4 cross-listed

01
Chiral interactions and superfluidity in the calcium isotopic chain
A. Scalesi🇸🇪 · A. Ekström🇸🇪 · C. Forssén🇸🇪 · G. Hagen🇺🇸
We perform ab initio calculations of three-point mass differences in the odd- and even-mass $^{39 - 49}$ Ca isotopes to probe nuclear superfluidity via empirical neutron pairing gaps. We also quantify the sensitivity of those gaps to the parameters of the interaction at mean-field level. Recent studies employing accurate chiral nuclear interactions have found these gaps to be too small. We show that experimental values can be reproduced at mean-field level by substantially increasing the attraction of the singlet $S$ -wave two-nucleon contact interaction, but doing so induces an unphysical bound state of the di-neutron. The sensitivity of these predictions to the full calibration of the nuclear interaction is then studied by performing Bayesian posterior sampling in a delta-full chiral effective field theory at third chiral order. We find that pairing gaps remain largely unaffected, leaving the explanation of nuclear superfluidity as a future task for improved many-body modeling and refined interactions at higher chiral orders.
nucl-thPRC(2026)·2 citations
02
The Silver Blaze Problem in QCD
Thomas D. Cohen🇺🇸
This article provides a pedagogical introduction to the Silver Blaze problem. This problem refers to the difficulty of reconciling to perspectives on QCD with a chemical potential. The first is the phenomenological fact that at $T = 0$ QCD remains in its ground state -- the vacuum -- with all physical observables unchanged whenever the magnitude of a chemical potential is less than some critical value. The second is the fact that in functional integral treatments, the inclusion of any nonzero chemical potential changes all eigenvalues of the Dirac operator for every gauge configuration, leading to a natural expectation that the functional determinants also changes, which leads to the expectation that physical observables should be altered. The problem amounts to explaining why nothing happens below the critical chemical potential. By focusing on the eigenvalues of $γ_{0}$ times the Dirac operator rather than the Dirac operator itself, it is possible to show that for QCD with two flavors and identical quark masses, an isospin chemical potential with a magnitude less than $m_{π}$ (and no baryon chemical potential), or a baryon chemical potential of less than $\frac{3}{2} m_{π}$ (and no isospin chemical potential), the functional integerals at $T = 0$ themselves remain unchanged in all configurations that contribute to the functional integral with non-vanishing weight. However, for $μ_{crit} μ_{B} > \frac{3}{2} m_{π}$ , the Silver Blaze phenomenon arises due to functional determinants having nontrivial phases that lead to cancellations between different gauge configurations. The mechanism leading to such cancellations remains unknown.
nucl-thhep-lathep-ph3 citations
03
Chemical potential differentials in the QCD phase diagram from heavy-ion isobar collisions
Joaquin Grefa🇺🇸 · Chun Yue Tsang🇺🇸 · Rajesh Kumar🇺🇸 · Veronica Dexheimer🇺🇸 · Claudia Ratti🇺🇸 · Zhangbu Xu🇺🇸
Temperature and baryon, charge, and strangeness chemical potentials characterize QCD matter under extreme conditions. Differences between these chemical potentials and their ratios probe conserved-charge correlations and the system's response in the multidimensional QCD phase diagram. We extract these quantities from STAR Ru+Ru and Zr+Zr isobar collisions using a Bayesian thermal analysis of hadron yields, which substantially reduces systematic uncertainties, and compare them with Taylor-expanded lattice-QCD and Chiral Mean Field model predictions. Isobar collisions thus emerge as a precision probe of four-dimensional QCD thermodynamics.
nucl-thhep-exhep-lathep-ph+15 citations
04
Competing decay modes and stability analysis of superheavy nuclei with Z = 120 using relativistic mean-field approach
Nishu Jain · M. Bhuyan · P. Mohr · Raj Kumar
We systematically study the competition between {\alpha}-decay and spontaneous fission in even-even superheavy nuclei with (Z=120) and 256 \leq A \leq 304 within the preformed cluster-decay model using microscopic inputs from relativistic mean-field calculations with the NL3 parameter set. The {\alpha}-decay half-lives are obtained from WKB barrier penetration with empirically determined preformation factors, self-consistent Q_{\alpha} values from RMF, and nuclear interaction potentials constructed using both M3Y and relativistic R3Y nucleon-nucleon forces, and are benchmarked against standard semi-empirical formulas. Our results predict reduced spontaneous fission probabilities and extended {\alpha}-decay chains toward the fermium region for isotopes with 296 \leq A \leq 304, with enhanced stability reflected in maxima of log_{10} T_{1/2} around neutron numbers N \approx 166-182. In particular, the nuclei 296,298,300,302,304_{120} are identified as the most favorable candidates for survival against fission, demonstrating the crucial role of shell effects, deformation, and pairing correlations and providing quantitative guidance for future experimental searches of Z=120 nuclei.
nucl-thNPA(2026)·0 citations
05
Cone-Dependent Jet Collisional Energy Loss in Finite QCD Medium
Magdalena Djordjevic🇷🇸 · Bojana Ilic🇷🇸 · Marko Djordjevic🇷🇸
We derive a compact HTL-resummed expression for the leading-order jet collisional energy loss in a finite-size, finite-temperature QCD medium. Defining the jet energy inside a cone of radius $R$ , we obtain the out-of-cone elastic energy loss with an explicit separation between contributions from the primary jet parton and recoiling medium partons. The result reproduces the known partonic limit as $R \to 0$ , vanishes for $R \to π$ , and applies to both light- and heavy-flavor jets. Numerically, the elastic component shows a pronounced non-linear $R$ dependence relative to the radiative baseline, and its importance increases with $R$ , becoming comparable to or exceeding the radiative contribution for sufficiently large jet radii. The path-length dependence remains close to linear for all $R$ , while the medium-response contribution can exceed $10%$ for realistic jet radii.
nucl-thhep-phPLB(2026)·2 citations
06
Medium separation scheme effects on the magnetized and cold two-flavor superconducting quark matter
Francisco X. Azeredo🇧🇷 · Dyana C. Duarte🇧🇷 · Ricardo L. S. Farias🇧🇷
We analyze the impact of the Medium Separation Scheme (MSS) on two-flavor color superconducting (2SC) dense quark matter under the influence of a constant external magnetic field. The effects of the proper treatment of the model divergences are examined through a comparison of different approaches, including the combined implementation of the Magnetic Field Independent Regularization (MFIR) and the MSS, as well as the standard use of smooth form factors. Our findings for the Nambu--Jona-Lasinio model emphasize the critical role of properly separating medium effects from vacuum contributions in the model. The combined MFIR-MSS scheme suppresses spurious unphysical oscillations, often misinterpreted in the literature as de Haas--van Alphen oscillations, and ensures the correct high-density behavior of the diquark condensate. Furthermore, within the MSS framework, the magnetization remains positive across the explored parameter space, in sharp contrast with the behavior obtained in the traditional approach.
↳ hep-phhep-lathep-thnucl-thPRD(2026)·4 citations
07
Nucleon axial-vector form factor and radius from radiatively-corrected antineutrino scattering data
Oleksandr Tomalak🇨🇳 · Aaron S. Meyer🇺🇸 · Clarence Wret🇬🇧 · Tejin Cai🇺🇸 · Richard J. Hill🇺🇸 · Kevin S. McFarland🇺🇸
The nucleon axial-vector form factor, $G_{A}$ , is critical to determine the electroweak interactions of leptons with nucleons. Important examples of processes influenced by $G_{A}$ are elastic (anti)neutrino-nucleon scattering and muon capture by the proton. Sparse experimental data results in a large uncertainty on the momentum dependence of $G_{A}$ and has motivated the consideration of new experimental probes and first-principles lattice quantum chromodynamics (QCD) evaluations. The comparison of new and precise theoretical predictions for $G_{A}$ with future experimental data necessitates the application of radiative corrections to experimentally-observable processes. We apply these corrections in the extraction of $G_{A}$ and the associated axial-vector radius from the recent MINERvA antineutrino-hydrogen data, compare the effects from radiative corrections to other uncertainties in neutrino scattering experiments, and discuss the comparison of lattice QCD evaluations to experimental measurements.
↳ hep-phhep-exhep-latnucl-ex+1PRD(2026)·5 citations
08
Scaling Properties of Two-Particle-Two-Hole Responses in Asymmetric Nuclei for Neutrino Scattering within the Relativistic Mean-Field Framework
V.L. Martinez-Consentino🇪🇸 · J. E. Amaro🇪🇸 · J. Segovia🇪🇸
We perform a systematic analysis of the nuclear dependence of two-particle-two-hole meson-exchange current contributions to inclusive lepton-nucleus scattering within the relativistic mean-field framework. We present microscopic calculations of nuclear responses for a set of 17 nuclei, ranging from helium to uranium, using a model with different Fermi momenta for protons and neutrons. We propose a novel scaling prescription based on the two-particle phase space and key nuclear parameters. The resulting description is accurate over a wide range of nuclear targets, with typical deviations below 10\%, and allows for a separate treatment of the different emission channels. In addition, a consistent benchmark against electron-scattering data is provided. The parametrization presented provides a practical framework for extending the responses to different nuclear targets in neutrino event generators.
↳ hep-phnucl-thUniverse(2026)·5 citations
09
The $Ω (2380)$ as a partner of the $Ω (2012)$
Yi-Yao Li🇨🇳 · Albert Feijoo🇪🇸 · Eulogio Oset🇪🇸
We present a study of the $Ω (2380)$ resonance and show that it is consistent with a dynamically generated state arising from the $K ˉ^{*} Ξ^{*}$ , $ω Ω$ , and $ϕ Ω$ interactions. In this picture, the $Ω (2380)$ is analogous to the $Ω (2012)$ , which is generated from the $K ˉ Ξ^{*}$ and $η Ω$ channels. The resulting mass, total width, and partial decay widths into the $K ˉ Ξ^{*}$ and $K ˉ^{*} Ξ$ channels are compatible with the available experimental data. We also discuss possible experimental observables that could provide further insight into the nature of this state.
↳ hep-phnucl-thPRD(2026)·3 citations

Affiliations

first authorsco-authorsvia INSPIRE