PaperPanorama
FAQ

Nuclear Theory·nucl-th

Wednesday·October 1, 2025

13 papers—6 primary·7 cross-listed

All13Primary6Cross-lists7
  1. 07

    Nonlocal effective field theory and its applications

    P. Wang🇨🇳 · Zhengyang Gao🇨🇳 · Fangcheng He🇺🇸 · Chueng-Ryong Ji🇺🇸 · W. Melnitchouk🇺🇸 · Y. Salamu🇨🇳

    We review recent applications of nonlocal effective field theory, focusing in particular on nonlocal chiral effective theory and nonlocal quantum electrodynamics (QED), as well as an extension of nonlocal effective theory to curved spacetime. For the chiral effective theory, we discuss the calculation of generalized parton distributions (GPDs) of the nucleon at nonzero skewness, along with the corresponding gravitational (or mechanical) form factors, within the convolution framework. In the QED application, we extend the nonlocal formulation to construct the most general nonlocal QED interaction, in which both the propagator and fundamental QED vertex are modified due to the nonlocal Lagrangian, while preserving the Ward-Green-Takahashi identities. For consistency with the modified propagator, a solid quantization is proposed, and the nonlocal QED is applied to explain the lepton anomalies without the introduction of new particles or interactions. Finally, with an extension of the chiral effective action to curved spacetime, we investigate the nonlocal energy-momentum tensor and gravitational form factors of the nucleon with a nonlocal pion-nucleon interaction.

    ↳ hep-phhep-exnucl-thSymmetry(2026)·1 citation
  2. 08

    Bulk viscosity from neutron decays to dark baryons in neutron star matter

    Steven P. Harris🇺🇸 · C.J. Horowitz🇺🇸

    The existence of a dark baryon that mixes with the neutron leads to the possibility of neutron decay into a dark sector. Such dark decays have been studied as possibly relevant for the neutron decay anomaly and for their potential impacts on neutron stars. The most popular formulation is a dark sector consisting of a dark baryon and a dark scalar , where a neutron in vacuum decays 1% or less of the time via the channel . In this work, we consider the effect of this additional neutron decay channel on transport in neutrons star mergers. We find that the neutron dark decay rate in medium is quite slow, and thus the dark baryons modify the dense matter equation of state in a way that decreases the Urca bulk viscosity by, at most, a factor of 2-3. However, if the neutron dark decay was to occur more rapidly, then the bulk viscosity at merger temperatures of tens of MeV would be strongly enhanced, potentially rapidly damping oscillations in merger environments and therefore providing a signature of slowly equilibrating matter in the merger.

    ↳ astro-ph.HEhep-phnucl-thPRD(2026)·5 citations
  3. 09

    Machine learning approach to QCD kinetic theory

    Sergio Barrera Cabodevila🇪🇸 · Aleksi Kurkela🇳🇴 · Florian Lindenbauer🇦🇹

    The effective kinetic theory (EKT) of QCD provides a possible picture of various non-equilibrium processes in heavy- and light-ion collisions. While there have been substantial advances in simulating the EKT in simple systems with enhanced symmetry, eventually, event-by-event simulations will be required for a comprehensive phenomenological modeling. As of now, these simulations are prohibitively expensive due to the numerical complexity of the Monte Carlo evaluation of the collision kernels. In this talk, we show how the evaluation of the collision kernels can be performed using neural networks paving the way to full event-by-event simulations.

    ↳ hep-phnucl-thEPJ Web Conf.(2026)·1 citation
  4. 10

    Pre-hydrodynamic jet momentum broadening beyond the jet quenching parameter

    Alois Altenburger🇦🇹 · Kirill Boguslavski🇦🇹 · Florian Lindenbauer🇦🇹

    We obtain the collision kernel and related dipole cross section during the initial nonequilibrium stages in heavy-ion collisions. These quantities are a crucial input for jet quenching calculations. We further compute the gluon splitting rates in the AMY formalism resulting from this nonequilibrium kernel. Comparing with thermal and commonly used forms, we find that particularly the gluon splitting rate for parton energies of the order of the hard effective temperature significantly differs from these approximations.

    ↳ hep-phnucl-thEPJ Web Conf.(2026)·0 citations
  5. 11

    Precision measurement and modelling of the threshold-free 210Pb {\beta} spectrum

    Shuo Zhang · Hao-Ran Liu · Ke Han · Xavier Mougeot · Paul-Antoine Hervieux · Tao Sun · Wen-Tao Wu · Robin Cantor · Jing-Kai Xia · Zhi Liu · Jun-Cheng Liang · Fu-You Fan and 4 other authors

    Beta decay is a fundamental process that governs nuclear stability and serves as a sensitive probe of the weak interaction and possible physics beyond the Standard Model of particle physics. However, precise measurements of complete decay spectra, particularly at low energies, remain experimentally and theoretically challenging. Here we report a high-precision, threshold-free measurement of the full decay spectrum of 210Pb to excited states of 210Bi, using a transition-edge sensor (TES)-based micro-calorimeter. This approach enables the detection of particle energies from 0 keV up to their endpoint by coincidence summing with subsequent de-excitation energy, thereby eliminating reconstruction artifacts near zero energy that have traditionally limited low-energy spectral accuracy. To our knowledge, this is the first complete, high-precision decay spectrum from 0 keV. The data resolve theoretical uncertainties associated with the atomic quantum exchange (AQE) effect. An accompanying ab initio theoretical framework, incorporating atomic, leptonic, and nuclear components, predicts a statistically significant (7.2 {}) enhancement in emission probability near zero energy, in agreement with the measurement and in contrast to models that omit AQE corrections. These results provide a new benchmark for decay theory at low energies, deepen our understanding of the weak interaction, and establish a critical foundation for searches for new physics, including dark matter interactions and precision studies of neutrinos.

    ↳ nucl-exnucl-thphysics.ins-det1 citation
  6. 12

    The Physics of Jet Quenching in Perturbative QCD

    Yacine Mehtar-Tani🇺🇸

    Hard processes in collider experiments typically produce QCD jets, which have long served as precision tests of QCD in the vacuum. More recently, heavy-ion programs at RHIC and the LHC have offered a novel perspective on jets, establishing them as unique probes of strongly interacting matter. Experimental observations, including the suppression of high- hadrons and jets, provide compelling evidence for the formation of a new state of matter and its strong coupling to energetic partons. These advances have motivated new theoretical approaches to jet quenching that go beyond standard perturbative techniques, aiming to elucidate the mechanisms of energy dissipation and thermalization of energetic partons in the quark-gluon plasma. This review highlights recent progress, beginning with a unified description of medium-induced radiation across the Landau-Pomeranchuk-Migdal regime and its role in turbulent gluon cascades. We then examine radiative corrections that renormalize the transport coefficient , the mechanism of color decoherence in multi-parton systems, and nonlinear QCD evolution equations for jet energy loss. Finally, we confront this framework with experimental measurements, underscoring the need for precision phenomenology to fully exploit the rich data sets from RHIC and the LHC.

    ↳ hep-phnucl-th21 citations
  7. 13

    Experimental overview of electromagnetic radiation in heavy-ion collisions

    Sebastian Scheid🇨🇭

    Electromagnetic (EM) probes such as photons and dileptons provide direct insight into the space-time evolution of the hot and dense matter formed in heavy-ion collisions. Being unaffected by strong interactions, they serve as penetrating messengers from all collision stages, from pre-equilibrium dynamics to the quark-gluon plasma (QGP) and hadronic phases. This contribution summarises recent experimental results on direct-photon and dilepton production from RHIC and LHC experiments, as well as at lower energies. Particular emphasis is given to the ongoing 'direct-photon puzzle', the study of universal scaling of direct-photon production over a large range of collision systems and energies. Recent dielectron measurements from ALICE, STAR, and HADES, as well as new experimental developments at the LHC, are presented, along with perspectives for future facilities.

    ↳ nucl-exnucl-thEPJ Web Conf.(2026)·4 citations

Affiliations

first authorsco-authorsvia INSPIRE