Nuclear Theory·nucl-th

Friday·March 27, 2026

10 papers—3 primary·7 cross-listed

01
Extracting Resonance Width from Lattice Quantum Monte Carlo Simulations Using Analytical Continuation Method
Zhong-Wang Niu · Shi-Sheng Zhang · Bing-Nan Lu
Nuclear lattice effective field theory (NLEFT) provides an efficient ab initio framework for computing low-lying states via imaginary-time projection. However, the extraction of unstable resonances, especially those with broad widths, remains a significant challenge. Traditional techniques such as the complex scaling method are often limited by sign problems or inherent statistical uncertainties. In this work, we present the first direct extraction of a nuclear resonance width within NLEFT by combining a high-precision, sign-problem-free nuclear interaction with the analytical continuation in the coupling constant (ACCC) approach. To address numerical instabilities in the ACCC framework, we implement a robust Pade solver based on singular value decomposition (SVD), incorporating ridge regularization and pole-safety criteria to ensure reliable extrapolation to the resonance pole. We detail the methodology and apply it to the unbound ground state of $^{5}$ He ( $J^{π} = 3/ 2^{-}$ ). Our calculation yields a resonance energy $E = 0.80 (10)$ MeV and a width $Γ = 1.05 (9)$ MeV, in agreement with recent experimental results ( $E_{exp} = 0.798$ MeV, $Γ_{exp} = 0.648$ MeV). This work establishes a practical and precise strategy for studying resonances within the ab initio lattice framework, paving the way for investigations of many-body resonances in exotic nuclei near the drip lines.
nucl-thPLB(2026)·1 citation
02
Proton-Neutron Pairing in N=Z Nuclei within the Quark-Meson-Coupling Energy Density Functional
T. Popa🇷🇴 · N. Sandulescu🇷🇴 · D. Gambacurta🇮🇹
We investigate the impact of isovector and isoscalar proton-neutron pairing correlations on the ground-state properties of even-even N=Z nuclei with mass numbers between A=16 and A=120. Nuclear mean fields are generated using the quark-meson coupling (QMC) energy density functional, while pairing correlations are treated within the quartet condensation model (QCM). Ground-state energies are obtained from axially deformed, self-consistent QMC+QCM calculations employing a zero-range pairing interaction with a density-dependent term derived consistently within the QMC framework. We show that proton-neutron pairing provides a significant contribution to the binding energies of N=Z nuclei, leading to improved agreement with experimental data.
nucl-th1 citation
03
Bayesian analysis of proton-proton fusion in chiral effective field theory
Vittorio Barlucchi🇩🇪 · Alex Gnech🇺🇸 · Scilla Degl'Innocenti🇮🇹 · Laura Elisa Marcucci🇮🇹
The astrophysical $S$ -factor for the proton-proton fusion is calculated in the low-energy regime for a variety of nuclear interactions and consistent nuclear currents, derived within chiral effective field theory. We estimate, for the first time, the theoretical uncertainty on the $S$ -factor due to the truncation of the chiral expansion of the currents using a Bayesian analysis. In order to reach an accuracy at the percent level in the calculation, the electromagnetic potential includes contributions beyond the leading Coulomb interaction, such as two-photon exchange and vacuum polarization. The initial proton-proton state is expanded in partial waves and only the $^{1} S_{0}$ contribution is included, as it is known that the other partial-waves effects are negligible. The low-energy constant entering the contact term in the weak axial current operator is calibrated to reproduce the Gamow-Teller matrix element in Tritium $β$ -decay. The value $S (0)$ is found to be $S (0) = (4.068 \pm 0.025) \times 1 0^{- 25} MeV b$ .
nucl-thastro-ph.SRhep-ph0 citations
04
Causal-Horizon Scaling of Quarkonium Suppression in Strong QCD Fields
Yi Yang🇹🇼
The simultaneous observation of strong sequential bottomonium suppression and small azimuthal anisotropy constrains the time scale and geometry of quarkonium dissociation in relativistic heavy-ion collisions. We investigate an early-time contribution in which strong pre-equilibrium color fields generate an effective proper-acceleration scale and an associated causal length. The maximal inverse causal-length scale is fixed through the phenomenological anchoring condition $T_{U, eff}^{m a x} ≃ T_{c}$ , while the local kinematic acceleration notation $T_{U, loc}$ is kept distinct from an equilibrium temperature. The survival probability is described by an event-averaged one-scale exponential ansatz. With no state-by-state adjustment, the resulting horizon component captures the main LHC state ordering and centrality trend. For the directly measured $Υ (2 S)$ to- $Υ (1 S)$ double ratio, the anchored horizon coefficient and one effective late-stage coefficient give a quantitative conditional description. Because both contributions are assigned the same centrality function, the data constrain their combined exponent rather than a unique partition between early- and late-stage suppression. At RHIC, the absolute $R_{AA}$ central values lie below the isolated horizon component, while the relative $2 S$ -to- $1 S$ suppression remains compatible with the predicted state-size hierarchy within present uncertainties. Because the proposed early factor is local and scalar, its contribution is identically $v_{2}^{H} = 0$ within the idealized factorized construction, consistent with current CMS measurements.
↳ hep-phhep-exnucl-exnucl-th1 citation
05
String-breaking statics and dynamics in a (1+1)D SU(2) lattice gauge theory
Navya Gupta🇺🇸 · Emil Mathew🇮🇳 · Saurabh V. Kadam🇺🇸 · Jesse R. Stryker🇺🇸 · Aniruddha Bapat🇺🇸 · Niklas Mueller🇺🇸 · Zohreh Davoudi🇺🇸 · Indrakshi Raychowdhury🇮🇳
String breaking is at the core of hadronization models of relevance to particle colliders. Yet, studies of string-breaking dynamics rooted in quantum chromodynamics remain fundamentally challenging. Tensor networks enable sign-problem-free studies of static and dynamical properties of lattice gauge theories. In this work, we develop and apply a tensor-network toolkit based on the loop-string-hadron formulation of an SU(2) lattice gauge theory in 1+1 dimensions with dynamical fermions. We apply this toolkit to study static and dynamical aspects of strings and their breaking in this theory. The simple, gauge-invariant, and local structure of the loop-string-hadron states and constraints removes the need to impose non-Abelian constraints in the algorithm, and allows for a systematic computation of observables at increasingly large bosonic cutoffs, and toward the infinite-volume and continuum limits. Our study of static strings yields a determination of the string tension in the continuum and thermodynamic limits. Our study of dynamical string breaking, performed at a fixed lattice spacing and system size, illuminates underlying processes at play during the quench dynamics of a string. The loop, string, and hadron description offers a systematic and intuitive way to diagnose these processes, including string expansion and contraction, endpoint splitting and particle shower, chain scattering events, and inelastic processes resulting from string dissociation and recombination, and particle production. We relate these processes to several features of the dynamics, such as energy transport, entanglement-entropy production, and correlation spreading. This work opens the way to future tensor-network studies of string breaking and particle production in increasingly complex lattice gauge theories.
↳ hep-lathep-phnucl-thquant-ph8 citations
06
Diffractive and photon-induced processes at the LHC: from the odderon discovery, the evidence for saturation to the search for axion-like particles
C. Royon🇺🇸
We discuss first the discovery of the odderon by the TOTEM and D0 collaborations. We then describe the gap between jets measurements sensitive to the high gluon density regime and the possible observation of saturation phenomenon in Pb Pb interactions. We also mention the sensitivity to beyond standard model physics and to the production of axion-like particles via photon photon interactions.
↳ hep-exhep-phnucl-exnucl-thActa Phys.Polon.B(2026)·1 citation
07
Curvature Corrections to the Yukawa Potential in Tolman Metrics
J. V. Zamperlini🇧🇷 · C. C. Barros Jr🇧🇷
This work investigates curvature-induced modifications to the Yukawa potential in static, spherically symmetric spacetimes described by Tolman metrics, focusing on their implications for compact stellar objects, with particular application to solutions IV and VI. Motivated by the interplay of quantum interactions and strong gravitational fields in systems like neutron stars, we derive explicit corrections to the Yukawa potential for these metrics. Contrary to previous findings suggesting that curvature corrections break the radial symmetry of the interacting potential near a highly charged black hole, we demonstrate that Tolman metric corrections preserve this symmetry in the local inertial frame. Numerical estimates for astrophysical objects reveal energy shifts of the order of $1 0^{- 34}$ MeV for solution IV. The Tolman VI solution, while singular at the center, yields comparable corrections for most of the fluid sphere radius. A detailed analysis of the repulsive or attractive nature of these curvature corrections for a local observer is provided for each scenario. These results highlight the role of spacetime geometry in shaping quantum interactions and provide a foundation for future studies of nuclear interactions within the context of relativistic stars.
↳ gr-qchep-phmath-phmath.MP+1Class.Quant.Grav.(2026)·0 citations
08
Photon production from gluon splitting and fusion induced by a magnetic field in heavy-ion collisions
Alejandro Ayala🇲🇽 · Santiago Bernal-Langarica🇲🇽 · José Jorge Medina-Serna🇲🇽 · Ana Julia Mizher🇧🇷
In heavy-ion collisions, an excess in photon production, together with a larger than expected positive elliptic flow, has been observed, a phenomenon commonly referred to as the direct photon puzzle. In this work we study the mechanism of photon production arising from gluon splitting and fusion during the pre-equilibrium stage in the presence of magnetic fields in peripheral heavy-ion collisions. We begin by analyzing the general tensor structure of the two-gluon one-photon vertex, computing it at the one-loop level for magnetic fields of arbitrary strength without resorting to additional approximations. Using these expressions, we calculate the contribution of gluon fusion and splitting to the photon yield, revealing that splitting dominates over fusion at low photon energies. Our results are compared with experimental data from the PHENIX collaboration. Finally, we incorporate a longitudinal anisotropy into the initial gluon distribution and find that it does not significantly alter the photon yield compared to an isotropic distribution.
↳ hep-phnucl-th1 citation
09
Binding Energy of Muonic Beryllium: Perturbative versus All--Order Calculations
Shikha Rathi🇮🇱 · Ulrich D. Jentschura🇺🇸 · Paul Indelicato🇫🇷 · Ben Ohayon🇮🇱
We compute the ground-state binding energy of muonic $^{9}$ Be in two ways: first, the fully perturbative treatment of the nuclear-size effect often employed in light systems, and second, an approach that accounts for the finite-nuclear-size to all orders (and is inspired by calculations otherwise employed for heavy muonic ions). The results are compared term by term and show that both approaches agree to better than one part-per-million of the total energy. The objective of this work is twofold. The first is practical: to provide a parametrization that allows the extraction of the $^{9}$ Be charge radius from recent and forthcoming experiments with high precision. The second is more conceptual: to act as a bridge between the community working on calculations for light systems and those focusing on heavy systems, demonstrating that the fully relativistic approach otherwise chosen for heavy systems can be enhanced to cover theoretical predictions for all charge numbers.
↳ physics.atom-phnucl-thJ.Phys.A(2026)·1 citation
10
Particle Physics and Gravitational Waves as complementary windows on the Universe
Steven D. Bass🇦🇹 · Laura Baudis🇨🇭 · Gianfranco Bertone🇳🇱 · Oliver Buchmueller🇬🇧 · Babette Döbrich🇩🇪 · Reinhard Genzel🇩🇪 · Anne M. Green🇬🇧 · Klaus Helbing🇩🇪 · Michèle Heurs · Karl Jakobs🇩🇪 · Markus Klute · Samaya Nissanke🇳🇱 and 7 other authors
Particle physics and gravitational waves provide complementary probes of the deep structure of the Universe. Gravitational waves from the mergers of neutron stars and black holes are sensitive to the structure of dense quark matter and to different dark matter scenarios. Measurements of stochastic gravitational waves backgrounds can teach us about possible first order phase transitions in the early Universe, including providing sensitivity to the TeV scale which is of key interest to future particle collider experiments. Gravitational waves measurements will also give new probes of the evolution and expansion of the Universe, complementary to measurements with electromagnetic radiation. This Perspectives article explores the physics synergies between the science opportunities provided by next generation gravitational waves measurements and particle physics experiments. Gravitational waves can also probe deep into the early Universe reaching physics much above possible collider energies if the signals can be detected.
↳ astro-ph.COgr-qchep-exhep-ph+11 citation

Affiliations

first authorsco-authorsvia INSPIRE