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Nuclear Theory·nucl-th

Monday·May 12, 2025

7 papers—2 primary·5 cross-listed

All7Primary2Cross-lists5
  1. 03

    [Submitted on 8 May 2025] (cross-list from hep-lat)

    Di-nucleons do not form bound states at heavy pion mass

    John Bulava🇩🇪 · M.A. Clark🇺🇸 · Arjun S. Gambhir🇺🇸 · Andrew D. Hanlon🇺🇸 · Ben Hörz🇩🇪 · Bálint Joó🇺🇸 · Christopher Körber🇩🇪 · Ken McElvain🇺🇸 · Aaron S. Meyer🇺🇸 · Henry Monge-Camacho🇺🇸 · Colin Morningstar🇺🇸 · Joseph Moscoso🇺🇸 and 7 other authors

    We perform a high-statistics lattice QCD calculation of the low-energy two-nucleon scattering amplitudes. In order to address discrepancies in the literature, the calculation is performed at a heavy pion mass in the limit that the light quark masses are equal to the physical strange quark mass, MeV. Using a state-of-the-art momentum space method, we rule out the presence of a bound di-nucleon in both the isospin 0 (deuteron) and 1 (di-neutron) channels, in contrast with many previous results that made use of compact hexaquark creation operators. In order to diagnose the discrepancy, we add such hexaquark interpolating operators to our basis and find that they do not affect the determination of the two-nucleon finite volume spectrum, and thus they do not couple to deeply bound di-nucleons that are missed by the momentum-space operators. Further, we perform a high-statistics calculation of the HAL QCD potential on the same gauge ensembles and find qualitative agreement with our main results. We conclude that di-nucleons do not form bound states at heavy pion masses and that previous identification of deeply bound di-nucleons must have arisen from a misidentification of the spectrum from off-diagonal elements of a correlation function.

    Comments:
    v2: small modifications suggested by the referee, consistent with published version; v1: 22 pages, 25 figures + appendices and more figures
    Subjects:
    High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2505.05547 [pdf]
    PRC(2026)·26 citations
  2. 04

    [Submitted on 8 May 2025] (cross-list from astro-ph.HE)

    Non-purely transverse Magnus force in superconducting neutron stars

    Oleg A. Goglichidze🇷🇺 · Mikhail E. Gusakov🇷🇺

    The force acting on a proton vortex in extreme type-II superconducting neutron star matter is studied in the limit of vanishing temperature. A detailed analysis is presented on how momentum is transferred from length scales on the order of the London penetration depth to the vortex core. To examine the momentum flux, expressions for proton and electron currents are derived for arbitrary distances from the vortex line. It is shown that, in the regime of a large electron mean free path, the only force acting directly on the vortex core is the Magnus force. Notably, the correction to the proton current near the vortex core generates a component of the Magnus force aligned with the incident current measured far from the vortex. This contribution, responsible for longitudinal force, is usually overlooked in the literature. The results obtained in this work for a relatively simple problem concerning the force on a vortex in cold matter of neutron stars may also be relevant to other superconducting systems.

    Comments:
    30 pages, 3 figures, accepted for publication in Phys. Rev. D
    Subjects:
    High Energy Astrophysical Phenomena (astro-ph.HE); Superconductivity (cond-mat.supr-con); Nuclear Theory (nucl-th)
    arXiv:
    2505.05628 [pdf]
    PRD(2025)·1 citation
  3. 05

    [Submitted on 9 May 2025] (cross-list from nucl-ex)

    Measurement of medium-induced acoplanarity in central Au-Au and pp collisions at GeV using direct-photon+jet and +jet correlations

    The STAR Collaboration

    The STAR Collaboration reports measurements of acoplanarity using semi--inclusive distributions of charged--particle jets recoiling from direct photon and triggers, in central Au+Au and collisions at GeV. Significant medium--induced acoplanarity broadening is observed for large but not small recoil jet resolution parameter, corresponding to recoil jet yield enhancement up to a factor of for trigger--recoil azimuthal separation far from . This phenomenology is indicative of the response of the Quark--Gluon Plasma to excitation, but not the scattering of jets off of its quasiparticles. The measurements are not well--described by current theoretical models which incorporate jet quenching.

    Comments:
    Submitted to PRL; 3 figures+1 figure in End Matter, accepted by PRC
    Subjects:
    Nuclear Experiment (nucl-ex); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2505.05789 [pdf]
    PRC(2026)·6 citations
  4. 06

    [Submitted on 9 May 2025] (cross-list from hep-ph)

    Calculation of the axial-vector coupling constant to two loops in covariant chiral perturbation theory

    Véronique Bernard🇫🇷 · Jambul Gegelia🇩🇪 · Shayan Ghosh🇩🇪 · Ulf-G. Meißner🇩🇪

    We present a calculation of the leading two-loop corrections to the axial-vector coupling constant in two covariant versions of two-flavor baryon chiral perturbation theory. Taking the low-energy constants from a combined analysis of elastic and inelastic pion-nucleon scattering, we find that these corrections are rather moderate.

    Comments:
    11 pages, 3 figures, published version, a few corrections, all conclusions unchanged
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2505.05941 [pdf]
    PLB(2025)·6 citations
  5. 07

    [Submitted on 9 May 2025] (cross-list from hep-ph)

    Mechanical form factors and densities of non-relativistic fermions

    Adam Freese🇺🇸

    The hadron physics community has been actively debating the interpretation of so-called mechanical properties of hadrons. Non-relativistic quantum-mechanical systems like the hydrogen atom have been appealed to in these debates as analogies. Since such appeals are likely to continue, it is important to have Galilei-covariant expressions for matrix elements of the energy-momentum tensor. In this work, I obtain Galilei-covariant breakdowns of such matrix elements into mechanical form factors, with a special focus on spin-half states. I additionally study the spatial densities associated with these form factors, using the pilot wave interpretation to guide their breakdown into contributions from internal structure and from quantum-mechanical effects such as wave packet dispersion. For completeness, I also obtain non-relativistic Breit frame densities.

    Comments:
    26 pages, version accepted for publication
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
    arXiv:
    2505.06135 [pdf]
    PRD(2025)·9 citations

Affiliations

first authorsco-authorsvia INSPIRE