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Nuclear Theory·nucl-th

Wednesday·December 10, 2025

10 papers—4 primary·6 cross-listed

All10Primary4Cross-lists6
  1. 05

    [Submitted on 8 Dec 2025] (cross-list from hep-ph)

    Theory of inverse beta decay for reactor antineutrinos

    Oleksandr Tomalak🇨🇳 · Qishan Liu🇨🇳 · Yu-Feng Li🇨🇳

    Inverse beta decay (IBD), , is the main detection channel for reactor antineutrinos in water- and hydrocarbon-based detectors. As reactor antineutrino experiments now target sub-percent-level sensitivity to oscillation parameters, a precise theoretical description of IBD, including recoil, weak magnetism, nucleon structure, and radiative corrections, becomes essential. In this work, we give a detailed and precise calculation of the total and differential cross sections for radiative IBD, . We use a heavy baryon chiral perturbation theory framework, systematically incorporating electroweak, electromagnetic, and strong-interaction corrections. We derive new analytic cross-section expressions, clarify the collinear structure of radiative corrections, and provide a systematic uncertainty analysis. We also discuss phenomenological applications for reactor antineutrino experiments, e.g., JUNO, and neutron decay. Our results enable sub-permille theoretical precision, supporting current and future experiments.

    Comments:
    57 pages, 12 figures, 1 table; version published in Physical Review D; text in footnote 10 and Introduction to Section 4 clarified; expression 192 added; Section 4.3 extended; minor text and figure corrections; Section 5.4 added; author list extended by authors who contributed to Section 5.4
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2512.07956 [pdf]
    Phys. Rev. D (2026)·8 citations
  2. 06

    [Submitted on 8 Dec 2025] (cross-list from hep-ph)

    Radiative corrections to inverse beta decay: a precision analysis for reactor neutrinos

    Oleksandr Tomalak🇨🇳

    We present a complete calculation of radiative corrections to the inverse beta decay reaction, , at reactor antineutrino energies using heavy-baryon chiral perturbation theory. Our analysis consistently incorporates quantum electrodynamics, chromodynamics, and electroweak contributions for the first time within this framework. We provide updated, high-precision cross-section predictions with a full error budget and present the positron energy spectrum, including radiative effects. The results are essential for normalizing the reactor antineutrino flux, determining neutrino oscillation parameters with subpercent accuracy, and searching for new physics at nuclear power plants.

    Comments:
    7 pages, 4 figures, version published in Physical Review Letters, extended discussions on the relation to the experiment, a change in Fig. 3, minor text edits
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2512.07957 [pdf]
    Phys. Rev. Lett. (2026)·5 citations
  3. 07

    [Submitted on 8 Dec 2025] (cross-list from hep-ph)

    (3+1)D event-by-event pre-equilibrium dynamics in heavy-ion collisions

    Xiaojian Du🇨🇳 · Sören Schlichting🇩🇪 · Jie Zhu🇨🇳

    So far a major source of uncertainty in the study of heavy-ion collisions arises from the early time dynamics which includes initial state and pre-equilibrium dynamics. The state-of-the-art framework, KoMPoST, employs non-equilibrium Green's functions to propagate the initial energy-momentum tensor to the hydrodynamic phase, yet currently only treats transverse plane dynamics under boost-invariant conditions. In this work, we extend KoMPoST to include non-boost-invariant responses to initial conditions, essential for accurately capturing the longitudinal structures observed in heavy-ion collisions. Non-boost-invariant fluctuations on top of a homogeneous background are evolved using (3+1)D response functions calculated in kinetic theory. To assess kinetic theory's transition towards hydrodynamic evolution, we systematically compare the out-of-equilibrium shear-stress tensor from KoMPoST-3D with estimates based on Navier-Stokes hydrodynamics. Subsequently, a comprehensive (3+1)D framework, McDIPPER+KoMPoST-3D+CLVisc+SMASH, is utilized to simulate the complete spacetime evolution of heavy-ion collisions. The sensitivity of key observables, including longitudinal structure of anisotropic flow, to variations in the hydrodynamic initialization time is thoroughly investigated.

    Subjects:
    High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
    arXiv:
    2512.08007 [pdf]
    PRD(2026)·3 citations
  4. 08

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

    Nucleon Structure from Basis Light-Front Quantization : Status and Prospects

    James P. Vary🇺🇸 · Chandan Mondal🇨🇳 · Siqi Xu🇺🇸 · Xingbo Zhao🇨🇳 · Yang Li🇨🇳

    We review recent advancements in understanding nucleon structure within the Basis Light-Front Quantization (BLFQ) framework--a fully relativistic, nonperturbative approach to solving quantum field theories. In its initial phase, we start with the leading Fock sector and an effective light-front Hamiltonian incorporating confinement and one-gluon exchange within which BLFQ can already successfully describe key nucleon observables. The framework has since been extended to include the next-to-leading Fock sector , enabling studies of gluonic contributions to the nucleon's internal structure, including gluon helicity, orbital angular momentum, and three-dimensional imaging through generalized and transverse momentum dependent parton distributions (GPDs and TMDs). Most recently, BLFQ has achieved a significant milestone by computing nucleon light-front wavefunctions as eigenstates of the QCD Hamiltonian without an explicit confining potential. These calculations, including Fock sectors up to , further develop the path to first-principles predictions of quark and gluon matter densities, helicity and transversity distributions, and spin observables, showing qualitative agreement with experimental and phenomenological results. Together, these developments highlight BLFQ's growing capacity to provide an increasingly complete and realistic picture of nucleon structure grounded in QCD.

    Comments:
    77 pages, 15 figures; Review article to appear in Eur. Phys. J. Spec. Top
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
    arXiv:
    2512.08283 [pdf]
    Eur.Phys.J.ST(2026)·14 citations
  5. 09

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

    -Meson Nucleon Scattering Length from Threshold Photoproduction on Light Nuclei

    Igor I. Strakovsky (GWU)🇺🇸 · William J. Briscoe (GWU)🇺🇸 · Philipp Gubler (JAEA)🇯🇵 · Jackson R. Pybus (LANL)🇺🇸 · Axel Schmidt (GWU)🇺🇸 · Alexander Somov (JLab)🇺🇸

    The quality of recent SRC/CT Collaboration photoproduction data off a He target from Hall~D at Jefferson Laboratory, combined with the feasibility of measuring the reaction close to the free-nucleon energy threshold, opens the door to using incoherent photoproduction to access a variety of interesting physics aspects. An example is an estimate of the scattering length on the bound proton obtained using the Vector Meson Dominance model. This value can be compared with that of the free proton from the GlueX Collaboration. One may then project what would be expected from the SRC/CT Collaboration Experiment E12--25--002, which was recently approved by the JLab PAC. Using a plane-wave theoretical model to generate quasi-data, we find the experiment could achieve a result of , an uncertainty competitive with that of the free-proton measurement. A comparison between the two would allow an evaluation of the effects of medium modification in the case of light nuclei.

    Comments:
    7 pages, 2 figures, 2 tables
    Subjects:
    High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
    arXiv:
    2512.08701 [pdf]
    PRC(2026)·3 citations
  6. 10

    [Submitted on 9 Dec 2025] (cross-list from astro-ph.HE)

    The Radius of PSR J0437-4715 from NICER Data

    M. C. Miller · A. J. Dittmann · I. M. Holt · F. K. Lamb · C. Chirenti · Z. Arzoumanian · J. Berteaud · S. Bogdanov · K. C. Gendreau · W. C. G. Ho · S. M. Morsink · P. S. Ray and 3 other authors

    Neutron star Interior Composition Explorer (NICER) data have been used to estimate the masses and radii of the rotation-powered millisecond pulsars PSR J00300451, PSR J07406620, PSR J04374715, PSR J12311411, and PSR J06143329, sometimes in joint analyses with X-ray Multi-Mirror (XMM-Newton) data. These measurements provide invaluable information about the properties of cold, catalyzed matter beyond nuclear saturation density. Here we present the results of our modeling of NICER data on PSR J04374715 using several different models of hot thermal X-ray emitting spots on the stellar surface. For this pulsar, previous Nuclear Spectroscopic Telescope Array (NuSTAR) observations established that there is also a modulated nonthermal component to the emission, but the previously published analysis of NICER data did not model this component. We find that the Bayesian evidence is significantly higher when the modulated nonthermal component is included, and that omission of this component leads to poor fits to the bolometric NICER data and thus risks bias in the resulting radius estimates. Our models, which we pursue to inferential convergence, therefore have modulated nonthermal emission, and our headline model has in addition three uniform-temperature thermally-emitting circular spots. Using this model, the symmetric 68% credible range in the radius is 11.8 km to 15.1 km, which at the independently-measured mass of is consistent with previous reports of the radius of the pulsar PSR J00300451. We discuss the implications of this measurement for the equation of state of dense matter.

    Comments:
    22 pages, 12 figures, submitted to The Astrophysical Journal Letters
    Subjects:
    High Energy Astrophysical Phenomena (astro-ph.HE); General Relativity and Quantum Cosmology (gr-qc); Nuclear Theory (nucl-th)
    arXiv:
    2512.08790 [pdf]
    ApJL(2026)·29 citations

Affiliations

first authorsco-authorsvia INSPIRE