Nuclear Theory·nucl-th

Thursday·October 16, 2025

7 papers—1 primary·6 cross-listed

01
Phenomenology of light baryon resonances
Michael Döring🇺🇸
Protons and neutrons are the building blocks of matter, glued together in nuclei by strong interactions. They can be excited by pions, real and virtual photons, neutrinos and other probes. These excitations are referred to as light baryon resonances. A short, pedagogical overview of the field is presented including experimental progress, interpretation of light baryon resonances, and a focus on analysis methods to extract the resonance spectrum from data.
nucl-thhep-phnucl-ex3 citations
02
On the maximum compactness of neutron stars
Luciano Rezzolla🇩🇪 · Christian Ecker🇩🇪
The stellar compactness, that is, the dimensionless ratio between the mass and radius of a compact star, $C := M / R$ , plays a fundamental role in characterising the gravitational and nuclear-physics aspects of neutron stars. Yet, because the compactness depends sensitively on the unknown equation of state (EOS) of nuclear matter, the simple question: ``how compact can a neutron star be?'' remains unanswered. To address this question, we adopt a statistical approach and consider a large number of parameterised EOSs that satisfy all known constraints from nuclear theory, perturbative Quantum Chromodynamics (QCD), and astrophysical observations. Next, we conjecture that, for any given EOS, the maximum compactness is attained by the star with the maximum mass of the sequence of nonrotating configurations. While we can prove this conjecture for a rather large class of solutions, its general proof is still lacking. However, the evidence from all of the EOSs considered strongly indicates that it is true in general. Exploiting the conjecture, we can concentrate on the compactness of the maximum-mass stars and show that an upper limit appears for the maximum compactness and is given by $C_{max} = 1/3$ . Importantly, this upper limit is essentially independent of the stellar mass and a direct consequence of perturbative-QCD constraints.
↳ gr-qcastro-ph.HEhep-phnucl-thSciPost Phys.(2026)·11 citations
03
New Spallation Background Rejection Techniques to Greatly Improve the Solar Neutrino Sensitivity of JUNO
Obada Nairat🇺🇸 · John F. Beacom🇺🇸 · Shirley Weishi Li🇺🇸
While the potential of the Jiangmen Underground Neutrino Observatory (JUNO) to measure solar neutrinos is known, realizing this potential requires new techniques to reduce detector backgrounds. One of the most serious backgrounds is due to the beta decays of unstable nuclei produced through muon breakup (spallation) of nuclei. This background is much more significant in JUNO compared to Super-Kamiokande due to JUNO's shallower depth and its lack of directional information. We present the first detailed theoretical calculations of spallation backgrounds in JUNO, showing the underlying physical processes and new ways to cut backgrounds while preserving signals. A key point is showing the importance of neutron tagging to identify hadronic showers, which are rare but produce almost all of the dangerous isotopes. With our new techniques, JUNO will be able to reduce deadtime (signal loss) by a factor of about 4.5 and to reduce the running time needed to meet sensitivity goals by a factor of two. This will give JUNO greatly improved sensitivity to $^{8}$ B and $h e p$ solar neutrinos, as we will explore in a separate paper.
↳ hep-phastro-ph.HEhep-exnucl-ex+2PRD(2026)·3 citations
04
Toward First-Principles Multi-Messenger Predictions: Coupling Nuclear Networks with GR Radiation-MHD in {\tt Gmunu}
Patrick Chi-Kit Cheong · Christopher L. Fryer
We present a new implementation of nuclear reaction networks in the \texttt{G}eneral-relativistic \texttt{mu}ltigrid \texttt{nu}merical (\texttt{Gmunu}) code, a framework for general relativistic radiation magnetohydrodynamics (GRRMHD). The extended code self-consistently evolves nuclear species coupled to hydrodynamics, magnetic fields, and neutrino radiation transport under the conformal flatness approximation to Einstein's equations. Four approximate nuclear networks are included, with stiff source terms integrated using implicit-explicit Runge-Kutta schemes. Validation is performed through benchmarks including conserved-to-primitive recovery with a tabulated stellar equation of state, one-zone silicon burning, and hydrodynamic tests of shock tubes, acoustic pulses, and detonation fronts of Type Ia supernovae. These tests confirm accurate coupling between nuclear reactions and fluid dynamics, conserving electron and nuclear mass fractions to machine precision. As an application, we conduct spherically symmetric core-collapse supernova simulations. The models reproduce the expected non-exploding behavior of standard progenitors, while enhanced neutrino heating revives the shock. Including nuclear burning modifies the post-shock composition and dynamics, converting silicon and oxygen layers into iron-group nuclei and strengthening the explosion. This demonstrates the impact of explosive burning on ejecta composition and shock evolution, and establishes the stability of the coupled GR radiation-MHD-nuclear framework. The implementation is fully compatible with multidimensional GRMHD simulations and represents the first GRRMHD code combining M1 neutrino transport with fully coupled nuclear burning.
↳ astro-ph.IMastro-ph.HEnucl-th2 citations
05
Searching for the QCD critical point through constant entropy density contours
Hitansh Shah🇺🇸 · Mauricio Hippert🇧🇷 · Jorge Noronha🇺🇸 · Claudia Ratti🇺🇸 · Volodymyr Vovchenko🇺🇸
We propose a novel method to locate the QCD critical point by constructing an expansion along contours of constant entropy density. Applying two independent analysis of lattice QCD data at zero baryon chemical potential, we find a critical point at $T_{c} = 114 \pm 7$ MeV and $μ_{B_{c}} = 602 \pm 62$ MeV for an expansion truncated at order $μ_{B}^{2}$ . This approach is consistent with recent lattice QCD results up to $μ_{B} / T \leq 3$ . A more precise determination of the required expansion coefficients from lattice simulations will be essential for reliably establishing the location of the QCD critical endpoint.
↳ hep-phnucl-thEPJ Web Conf.(2026)·0 citations
06
A short review on QCD sum rule studies of P-wave single heavy baryons
Xuan Luo🇨🇳 · Shu-Wei Zhang🇨🇳 · Hua-Xing Chen🇨🇳 · Atsushi Hosaka🇯🇵 · Niu Su🇨🇳 · Hui-Min Yang🇨🇳
Over the past few decades, the study of singly heavy baryons has entered a golden era, with numerous excited states observed by experimental collaborations. Various theoretical approaches have been developed to investigate their properties, with the QCD sum rule method being one of the most widely applied. This paper provides a review of these QCD sum rule studies. Over the last ten years, we have systematically studied $P$ -wave singly heavy baryons using QCD sum rules and light-cone sum rules within the framework of heavy quark effective theory. These $P$ -wave singly heavy baryons can explain many excited heavy baryons, including the $Λ_{c} (2595)^{+}$ , $Λ_{c} (2625)^{+}$ , $Ξ_{c} (2790)^{0/ +}$ , $Ξ_{c} (2815)^{0/ +}$ , $Σ_{c} (2800)^{0}$ , $Ξ_{c} (2882)^{0}$ , $Ξ_{c} (2923)^{0}$ , $Ξ_{c} (2939)^{0}$ , $Ξ_{c} (2965)^{0}$ , $Ω_{c} (3000)^{0}$ , $Ω_{c} (3066)^{0}$ , $Ω_{c} (3090)^{0}$ , $Ω_{c} (3050)^{0}$ , $Ω_{c} (3119)^{0}$ , $Λ_{b} (5912)^{0}$ , $Λ_{b} (5920)^{0}$ , $Ξ_{b} (6087)^{0}$ , $Ξ_{b} (6095)^{0} / Ξ_{b} (6100)^{-}$ , $Σ_{b} (6097)^{\pm}$ , $Ξ_{b} (6227)^{-}$ , $Ω_{b} (6316)^{-}$ , $Ω_{b} (6330)^{-}$ , $Ω_{b} (6340)^{-}$ , and $Ω_{b} (6350)^{-}$ , etc. Furthermore, we predict additional $P$ -wave singly heavy baryons, including two $Λ_{b}$ states, two $Ξ_{b}$ states, three $Σ_{b}$ states, three $Ξ_{b}^{'}$ states, two $Ω_{b}$ states, two $Λ_{c}$ states, two $Ξ_{c}$ states, three $Σ_{c}$ states, and one $Ω_{c}$ state, all with relatively narrow decay widths, making them viable candidates for experimental observation. The study of singly heavy baryons is closely related to two meaningful questions:"What is the shortest possible lifetime of an observable particle?" and "How can one generally describe approximate (flavor) symmetries?".
↳ hep-phhep-exhep-thnucl-ex+1AAPPS Bull.(2026)·9 citations
07
First simultaneous analysis of transverse momentum dependent and collinear parton distributions in the proton
P. C. Barry🇺🇸 · A. Prokudin🇺🇸 · T. Anderson🇺🇸 · C. Cocuzza🇺🇸 · L. Gamberg🇺🇸 · W. Melnitchouk🇺🇸 · E. Moffat🇺🇸 · D. Pitonyak🇺🇸 · J.-W. Qiu🇺🇸 · N. Sato🇺🇸 · A. Vladimirov🇪🇸 · R. M. Whitehill🇺🇸
We present the first simultaneous global QCD analysis of unpolarized transverse momentum dependent (TMD) and collinear parton distribution functions (PDFs) in the proton. Our study incorporates data from deep-inelastic scattering, Drell-Yan, inclusive weak boson, $W$ +\,charm, and jet production involving PDFs, as well as TMD Drell-Yan and $Z$ -boson production data from fixed target and collider experiments sensitive to both TMD and collinear distributions. The analysis is performed at next-to-next-to-leading logarithmic accuracy for QCD resummation in TMD observables and next-to-leading order for observables described in collinear factorization. The combined analysis improves knowledge of both TMD and collinear PDFs, particularly in the sea-quark sector, providing a consistent simultaneous description of the aforementioned observables.
↳ hep-phhep-exhep-latnucl-th19 citations

Affiliations

first authorsco-authorsvia INSPIRE

Phenomenology of light baryon resonances

On the maximum compactness of neutron stars

New Spallation Background Rejection Techniques to Greatly Improve the Solar Neutrino Sensitivity of JUNO

Toward First-Principles Multi-Messenger Predictions: Coupling Nuclear Networks with GR Radiation-MHD in {\tt Gmunu}

Searching for the QCD critical point through constant entropy density contours

A short review on QCD sum rule studies of P-wave single heavy baryons

First simultaneous analysis of transverse momentum dependent and collinear parton distributions in the proton

Affiliations