PaperPanorama
FAQ

Nuclear Theory·nucl-th

Monday·June 9, 2025

11 papers—5 primary·6 cross-listed

All11Primary5Cross-lists6
  1. 06

    Measuring spin correlation between quarks during QCD confinement

    The STAR Collaboration

    The vacuum is now understood to possess a rich and complex structure, characterized by fluctuating energy fields and a condensate of virtual quark-antiquark pairs. The spontaneous breaking of the approximate chiral symmetry, signaled by the nonvanishing quark condensate , is dynamically generated through topologically nontrivial gauge configurations such as instantons. The precise mechanism linking the chiral symmetry breaking to the mass generation associated with quark confinement remains a profound open question in Quantum Chromodynamics (QCD) - the fundamental theory of strong interaction. High energy proton-proton collisions could liberate virtual quark-antiquark pairs from the vacuum that subsequently undergo confinement to form hadrons, whose properties could serve as probes into QCD confinement and the quark condensate. Here, we report evidence of spin correlations in hyperon pairs inherited from spin-correlated strange quark-antiquark virtual pairs. Measurements by the STAR experiment at the Relativistic Heavy-Ion Collider (RHIC) at Brookhaven National Laboratory reveal a relative polarization signal of that links the virtual spin-correlated quark pairs from the QCD vacuum to their final-state hadron counterparts. Crucially, this correlation vanishes when the hyperon pairs are widely separated in angle, consistent with the decoherence of the quantum system. Our findings provide a new experimental paradigm for exploring the dynamics and interplay of quark confinement and entanglement.

    ↳ hep-exhep-phhep-thnucl-ex+1Nature(2026)·37 citations
  2. 07

    Investigation of P levels near the proton threshold by Nuclear Resonance Fluorescence and the impact on the Si(p,)P thermonuclear rate

    David Gribble (1 and 2) · Christian Iliadis (1 and 2) · Robert V.F. Janssens (1 and 2) · Udo Friman-Gayer (3 and 2) · Akaa D. Ayangeakaa (1 and 2) · Art Champagne (1 and 2) · Emily Churchman (1 and 2) · William Fox (4 and 2) · Steven Frye (1 and 2) · Xavier K.-H. James (1 and 2) · Samantha R. Johnson (1 and 2) · Richard Longland (4 and 2) and 4 other authors

    We investigated the nuclear structure of P near the proton threshold using Nuclear Resonance Fluorescence (NRF) to refine the properties of key resonances in the Si(p,)P reaction, which is critical for nucleosynthesis in stellar environments. Excitation energies and spin-parities were determined for several states, including two unobserved resonances at ~keV and ~keV. The angular correlation analysis enabled the first unambiguous determination of the orbital angular momentum transfer for these states. These results provide a significant update to the Si(p,)P thermonuclear reaction rate, with direct implications for models of nucleosynthesis in globular clusters and other astrophysical sites. The revised rate is substantially lower than previous estimates at temperatures below ~MK, affecting predictions for silicon isotopic abundances in stellar environments. Our work demonstrates the power of NRF in constraining nuclear properties, and provides a framework for future studies of low-energy resonances relevant to astrophysical reaction rates.

    ↳ nucl-exastro-ph.SRnucl-thPRC(2025)·1 citation
  3. 08

    Pathfinding Quantum Simulations of Neutrinoless Double-Beta Decay

    Ivan A. Chernyshev🇺🇸 · Roland C. Farrell🇺🇸 · Marc Illa🇺🇸 · Martin J. Savage🇺🇸 · Andrii Maksymov🇺🇸 · Felix Tripier🇺🇸 · Miguel Angel Lopez-Ruiz🇺🇸 · Andrew Arrasmith🇺🇸 · Yvette de Sereville🇺🇸 · Aharon Brodutch🇺🇸 · Claudio Girotto🇺🇸 · Ananth Kaushik🇺🇸 · Martin Roetteler🇺🇸

    We present results from co-designed quantum simulations of the neutrinoless double-beta decay of a simple nucleus in 1+1D quantum chromodynamics using IonQ's Forte-generation trapped-ion quantum computers. Electrons, neutrinos, and up and down quarks are distributed across two lattice sites and mapped to 32 qubits, with an additional 4 qubits used for flag-based error mitigation. A four-fermion interaction is used to implement weak interactions, and lepton-number violation is induced by a neutrino Majorana mass. Quantum circuits that prepare the initial nucleus and time evolve with the Hamiltonian containing the strong and weak interactions are executed on IonQ Forte Enterprise. Enabled by tuned model parameters, lepton-number violation is observed in real time, providing a clear signal of neutrinoless double-beta decay. This was made possible by co-designing the simulation to maximally utilize the all-to-all connectivity and native gate-set available on IonQ's quantum computers. Quantum circuit compilation techniques and co-designed error-mitigation methods, informed from executing benchmarking circuits with up to 2,356 two-qubit gates, enabled observables to be extracted with high precision. We discuss the potential of future quantum simulations to provide yocto-second resolution of the reaction pathways in these, and other, nuclear processes.

    ↳ quant-phhep-lathep-phnucl-thNature Commun.(2026)·17 citations
  4. 09

    Center vortices in the novel phase of staggered fermions

    Jackson A. Mickley🇦🇺 · Derek B. Leinweber🇦🇺 · Daniel Nogradi🇭🇺

    The geometry of center vortices is studied in the novel lattice-artefact phase that appears with staggered fermions to elucidate any insight provided by the center-vortex degrees of freedom. For various numbers of fermion flavors, the single-site shift symmetry of the staggered-fermion action is broken in a finite region of the phase space. Simulations are performed with six degenerate fermion flavors and a range of values that span the phase boundary. Center vortices are demonstrated to capture the broken shift symmetry that manifests in the unphysical phase. This persists at the level of each individual plaquette orientation, where it is revealed that only the plaquettes that span the broken dimension are affected. Several bulk center-vortex quantities, including the vortex and branching point densities, are considered to highlight other aspects of vortex geometry sensitive to the unphysical phase. A slight preference for the plaquettes affected by the broken shift symmetry to be pierced by a vortex is observed. This translates also to a greater branching point density in three-dimensional slices that span the broken dimension. Combined, these findings provide a novel characterization of the unphysical phase in terms of the fundamental center degrees of freedom.

    ↳ hep-lathep-phhep-thnucl-thPRD(2025)·0 citations
  5. 10

    Angela and the electric dipole response -- giant and pygmy, hot and cold, isoscalar and isovector

    Peter von Neumann-Cosel (1,2) ((1) Institut für Kernphysik, Technische Universität Darmstadt, Darmstadt, Germany, (2) Norwegian Nuclear Research Center and Department of Physics, University of Oslo, Oslo, Norway)

    The impact of Angela Bracco's work on the electric dipole response of nuclei is discussed using three examples of current nuclear structure problems: disentangling different contributions to the decay width of the giant dipole resonance, the equivalence of photo- absorption and emission and the nature of the pygmy dipole resonance.

    ↳ nucl-exnucl-thEPJA(2025)·1 citation
  6. 11

    Initial stage jet momentum broadening in tBLFQ formalism

    Dana Avramescu🇫🇮 · Carlos Lamas🇪🇸 · Tuomas Lappi🇫🇮 · Meijian Li🇪🇸 · Carlos A. Salgado🇪🇸

    We study the momentum broadening of a high-energy quark jet in the large density gluon medium created right after the collision of two ultrarelativistic heavy nuclei, the Glasma. Previous Glasma studies modeled the jet as a classical probe particle, for which position and momentum are simultaneously determined. In this work, we use the light-front QCD Hamiltonian formalism to treat the jet as a fully quantum state. We compute its real-time evolution while propagating through the Glasma classical background fields, which act as an interaction potential in the quantum evolution of the jet. We present results for the momentum broadening and jet quenching parameter of a jet at mid-rapidity, with special emphasis on the anisotropies between the longitudinal and transverse directions relative to the collision axis. In addition, we compare our results to classical calculations, and initiate a study of the distinction between kinetic and canonic momentum in the context of jet momentum broadening.

    ↳ hep-phnucl-thEPJ Web Conf.(2025)·3 citations

Affiliations

first authorsco-authorsvia INSPIRE