Nuclear Theory·nucl-th

Tuesday·November 4, 2025

20 papers—12 primary·8 cross-listed

13
The $θ$ -term effects on isospin asymmetric hot and dense quark matter
Lei Zhang🇨🇳 · Lu-Meng Liu🇨🇳 · Mei Huang🇨🇳
We investigate the impact of the CP-violating $θ$ term on isospin symmetry breaking in quark matter and compact star properties using a two-flavor Nambu-Jona-Lasinio (NJL) model. By incorporating the $θ$ parameter through the Kobayashi-Maskawa-'t Hooft (KMT) determinant interaction, we derive the thermodynamic potential and gap equations under finite temperature, baryon chemical potential, and isospin chemical potential. At zero temperature and baryon density, $θ$ suppresses conventional chiral ( $σ$ ) and pion ( $π$ ) condensates while promoting pseudo-scalar ( $η$ ) and scalar-isovector ( $δ$ ) condensates, thereby reducing the critical isospin chemical potential $μ_{I}^{crit}$ for spontaneous symmetry breaking. For $θ = π$ , a first-order phase transition emerges at $μ_{I}^{crit} = 0.021$ GeV, accompanied by CP symmetry restoration. Extending the investigation to finite temperature and baryon chemical potential reveals that these $θ$ -term-induced effects persist. Axion effects (modeled via $θ \equiv a / f_{a}$ ) stiffen the equation of state (EOS) of non-strange quark stars, increasing their maximum mass and radii, in agreement with multimessenger constraints from pulsar observations and gravitational wave events. These results establish $θ$ as a critical parameter modulating both the Quantum Chromodynamics (QCD) phase structure and compact star observables.
↳ hep-phnucl-thPRD(2025)·2 citations
14
Energy Correlators from Partons to Hadrons: Unveiling the Dynamics of the Strong Interactions with Archival ALEPH Data
Hannah Bossi🇺🇸 · Yi Chen🇺🇸 · Yu-Chen Chen🇺🇸 · Max Jaarsma🇳🇱 · Yibei Li🇩🇪 · Jingyu Zhang🇺🇸 · Ian Moult🇺🇸 · Wouter Waalewijn🇳🇱 · Hua Xing Zhu🇨🇳 · Anthony Badea🇺🇸 · Austin Baty🇺🇸 · Christopher McGinn🇺🇸 and 3 other authors
Quantum Chromodynamics (QCD) is a remarkably rich theory exhibiting numerous emergent degrees of freedom, from flux tubes to hadrons. Their description in terms of the underlying quarks and gluons of the QCD Lagrangian remains a central challenge of modern physics. Colliders offer a unique opportunity to probe these phenomena experimentally: high energy partons produced from the QCD vacuum excite these emergent degrees, imprinting their dynamics in correlations in asymptotic energy flux. Decoding these correlations requires measurements with exceptional angular resolution, beyond that achieved in previous measurements. Recent progress has enabled precision calculations of energy flux on charged particles alone, allowing data-theory comparisons for measurements using high resolution tracking detectors. In this Letter, we resurrect thirty-year-old data from the ALEPH tracker, and perform a high angular resolution measurement of the two-point correlation of energy flux, probing QCD over three orders of magnitude in scale in a single measurement. Our measurement unveils for the first time the full spectrum of the correlator, including light-ray quasi-particle states, flux-tube excitations, and their transitions into confined hadrons. We compare our measurement with record precision theoretical predictions, achieving percent level agreement, and revealing interesting new phenomena in the confinement transitions. More broadly, we highlight the immense potential of this newly unlocked archival data set, the so called "recycling frontier", and emphasize synergies with ongoing and future collider experiments.
↳ hep-phhep-exhep-thnucl-ex+131 citations
15
Hadronic scattering in (1+1)D SU(2) lattice gauge theory from tensor networks
João Barata🇨🇭 · Juan Hormaza🇨🇴 · Zhong-Bo Kang🇺🇸 · Wenyang Qian🇪🇸
We present a first real-time study of hadronic scattering in a (1+1)-dimensional SU(2) lattice gauge theory with fundamental fermions using tensor-network techniques. Working in the gaugeless Hamiltonian formulation -- where the gauge field is exactly integrated out and no truncation of the electric flux is required -- we investigate scattering processes across sectors of fixed global baryon number $B = 0, 1, 2$ . These correspond respectively to meson-meson, meson-baryon, and baryon-baryon collisions. At strong coupling, the $B = 0$ and $B = 2$ channels exhibit predominantly elastic dynamics closely resembling those of the U(1) Schwinger model. In contrast, the mixed $B = 1$ sector shows qualitatively new behavior: meson and baryon wave packets become entangled during the collision, and depending on their initial kinematics, the slower state becomes spatially delocalized while the faster one propagates ballistically. We characterize these processes through local observables, entanglement entropy, and the information-lattice, which together reveal how correlations build up and relax during the interaction. Our results establish a first benchmark for non-Abelian real-time scattering from first principles and open the path toward quantum-simulation studies of baryon-number dynamics and inelastic processes in gauge theories.
↳ hep-lathep-phnucl-thquant-phJHEP(2026)·14 citations
16
Empirical Reconstruction of the JSNS $^{2}$ KDAR $ν_{μ}$ - $^{12}$ C Missing-Energy Spectrum with a Two-Ex-Gaussian and Generalized-Tail Model
Kyung Kwang Joo🇰🇷 · Jubin Park🇰🇷 · Minkyu Lee🇰🇷 · Myung-Ki Cheoun🇰🇷
Recent analyses of the JSNS $^{2}$ monoenergetic $ν_{μ}$ scattering on $^{12}$ C at 235.5~MeV have compared the measured missing-energy spectrum with several nuclear models, including \textsc{NuWro}, \textsc{GiBUU}, and RMF+Achilles. While these models reproduce the overall peak position, their respective $χ^{2}$ values of $35.5$ , $176.8$ , and $58.1$ indicate that none can simultaneously describe the spectral width and the high-energy tail, reflecting limitations in the treatment of binding energy, two-particle--two-hole (2p-2h) excitations, and final-state interactions (FSI). To address these discrepancies, we introduce an empirical yet physically motivated representation of the spectrum based on two exponentially modified Gaussian (ex-Gaussian) components for p- and s-shell knockout and a generalized power-exponential continuum term describing multinucleon and FSI-induced strength. The fit reproduces the JSNS $^{2}$ data within the fitted energy range with $χ^{2} = 8.0$ for 6 degrees of freedom. yielding parameters that quantify asymmetric broadening of the s-shell while preserving a narrow quasielastic p-shell response. This compact model demonstrates that a minimal empirical framework can capture key features of the nuclear response and provides a useful reference for phenomenological comparisons and future studies of quasielastic and 2p-2h dynamics in the few-hundred-MeV regime.
↳ hep-phnucl-th0 citations
17
In-medium mass shifts of $B_{c}^{(*)}, B_{s}^{(*)}$ and $D_{s}^{(*)}$ mesons
K. Tsushima🇧🇷 · S.L.P.G. Beres🇧🇷 · G.N. Zeminiani🇧🇷
We present our predictions for the Lorentz scalar mass shifts of two-flavored heavy mesons, $B_{c}^{(*)}, B_{s}^{(*)}$ and $D_{s}^{(*)}$ in symmetric nuclear matter. The in-medium mass shifts are estimated by evaluating the lowest order one-loop self-energies of the mesons based on a flavor-SU(5) effective Lagrangian approach. In-medium properties necessary for the estimates are calculated by the quark-meson coupling (QMC) model. The enhanced self-energies of the mesons in symmetric nuclear matter relative to those in free space, yield the negative mass shifts of these mesons.
↳ hep-phhep-exhep-latnucl-ex+1EPJ Web Conf.(2026)·0 citations
18
Three-dimensional sizes and shapes of pion emission in heavy-ion collisions
Daniel Kincses🇭🇺 · Emese Arpasi🇭🇺 · Laszlo Kovacs🇭🇺 · Marton Nagy🇭🇺 · Mate Csanad🇭🇺
In the era of precision measurements in high-energy heavy-ion physics, there is an increasing expectation towards phenomenological and theoretical studies to provide a better description of data. In recent years, multiple experiments have confirmed through two-pion Bose-Einstein correlation measurements that the shape of the two-pion pair source can be well described by Levy-stable distributions. However, direct comparisons of new phenomenological results with the data are still needed to understand the underlying phenomena and learn more about the nature of pion emission. In this paper, we present a three-dimensional analysis of the two-pion source in Monte-Carlo simulations of Au+Au collisions at 200 GeV per nucleon collision energy, and discuss a detailed comparison with the most recent centrality-dependent measurements from the PHENIX Collaboration.
↳ nucl-exhep-phnucl-thEPJC(2026)·5 citations
19
Skewness-dependent moments of the pion GPD from nonlocal quark-bilinear correlators
Xiang Gao🇺🇸 · Swagato Mukherjee🇺🇸 · Qi Shi🇺🇸 · Fei Yao🇺🇸 · Yong Zhao🇺🇸
We present lattice QCD calculations of the odd Mellin moments of pion valence-quark generalized parton distribution (GPD) up to fifth order, $⟨ x^{4} ⟩$ , and for the skewness range $[- 0.33, 0]$ using operator product expansion of bilocal quark-bilinear operators. The calculations are performed on an ensemble with lattice spacing $a = 0.04 fm$ and valence pion mass $300$ $MeV$ , employing boosted pion states with momenta up to 2.428 GeV and momentum transfers reaching 2.748 GeV $^{2}$ . We employ ratio-scheme renormalization and next-to-leading-logarithmic resummed perturbative matching. At zero skewness, our results are consistent with previous lattice studies. By combining matrix elements at multiple values of skewness and momentum transfer, skewness-dependent moments are obtained through simultaneous polynomiality-constrained fits.
↳ hep-lathep-phnucl-exnucl-thPRD(2026)·14 citations
20
Uncertainties in the production of iron-group nuclides in core-collapse supernovae from Monte Carlo variations of reaction rates
Nobuya Nishimura · Carla Froehlich · Thomas Rauscher
Core-collapse supernovae, occurring at the end of massive star evolution, produce heavy elements, including those in the iron peak. Although the explosion mechanism is not yet fully understood, theoretical models can reproduce optical observations and observed elemental abundances. However, many nuclear reaction rates involved in explosive nucleosynthesis have large uncertainties, impacting the reliability of abundance predictions. To address this, we have previously developed a Monte Carlo-based nucleosynthesis code that accounts for reaction rate uncertainties and has been applied to nucleosynthesis processes beyond iron. Our framework is also well suited for studying explosive nucleosynthesis in supernovae. In this paper, we investigate 1D explosion models using the "PUSH method", focusing on progenitors with varying metallicities and initial masses around $M_{ZAMS} = 16 M_{⊙}$ . Detailed post-process nucleosynthesis calculations and Monte Carlo analyses are used to explore the effects of reaction rate uncertainties and to identify key reaction rates in explosive nucleosynthesis. We find that many reactions have little impact on the production of iron-group nuclei, as these elements are primarily synthesized in the nuclear statistical equilibrium. However, we identify a few "key reactions" that significantly influence the production of radioactive nuclei, which may affect astrophysical observables. In particular, for the production of $^{44}$ Ti, we confirm that several traditionally studied nuclear reactions have a strong impact. However, determining a single reaction rate is insufficient to draw a definitive conclusion.
↳ astro-ph.SRnucl-exnucl-thMNRAS(2026)·1 citation

Affiliations

first authorsco-authorsvia INSPIRE