Nuclear Theory·nucl-th

Friday·February 27, 2026

17 papers—9 primary·8 cross-listed

10
Fluctuation-Dissipation Relation for Hard Partons in a Gluonic Plasma
Amit Kumar🇨🇦 · Abhijit Majumder🇺🇸 · Ismail Soudi🇩🇪 · Johannes Heinrich Weber🇩🇪
We derive a fluctuation dissipation relation connecting the drag and diffusion jet transport coefficients for an energetic light quark traversing a non-perturbative thermalized gluon plasma. The hard quark is taken to be close to on-shell, with an energy scale parametrically larger than the medium temperature. We introduce a general complex-valued function for each transport coefficient. Evaluating these in the deep Euclidean momentum region enables their expression in terms of local operators. Using contour-integration techniques, we relate these local operators, after vacuum subtraction, to the physical transport coefficients that arise along a branch cut, close to light-like dispersion. The derived relation relates the longitudinal drag coefficient to the longitudinal and transverse diffusion coefficients, and the thermal gluon condensate.
↳ hep-phhep-latnucl-th0 citations
11
Flavorful Lepton Number Violation at the EIC
Sebastián Urrutia Quiroga🇺🇸 · Vincenzo Cirigliano🇺🇸 · Wouter Dekens🇺🇸 · Kaori Fuyuto🇯🇵 · Emanuele Mereghetti🇺🇸
We explore the prospects of detecting flavorful lepton number violation at the Electron-Ion Collider (EIC) through resonant production of heavy neutral leptons (HNLs), resulting in $e^{-} p \to ℓ_{α}^{+} + k j + X$ , where $α \in {e, μ, τ}$ and $k$ denotes the number of jets. We work in the $ν$ SMEFT framework of the Standard Model Effective Field Theory augmented with $n$ singlet HNLs, one of which is in the mass range $10 - 100$ ~GeV, within kinematic reach of the EIC. To explore the EIC sensitivity, we focus on the HNL production mechanism induced by mixing with light neutrinos. We study kinematic distributions for signal and backgrounds, including hadronization and detector effects, and suggest a set of cuts to minimize backgrounds. In the mass range considered, we find that the EIC with muon detection capabilities and an integrated luminosity of $100 fb^{- 1}$ can reach sensitivities comparable to the strongest direct (LHC) and indirect constraints, and is especially relevant in the $ν$ SMEFT framework beyond dimension four. Our study motivates further assessment of muon detection capabilities at the EIC and $τ$ hadronic reconstruction, as well as a more general theoretical analysis involving production mechanisms mediated by higher-dimensional operators in the effective theory.
↳ hep-phhep-exnucl-exnucl-th1 citation
12
The 2027-2034 Vision for Nuclear Physics in Canada, with an outlook to 2041
Corina Andreoiu · Svetlana Barkanova · Gregory Christian · Alexandros Gezerlis · Garth Huber · Jeffery W. Martin · Ruben Sandapen
The Canadian subatomic physics community establishes its scientific, and thus funding, priorities through periodic Long-Range Plans (LRP). The community is now putting together a new LRP, which will be in effect from 2027 through 2034, with its scope extending through 2041. As part of this process, the Canadian Institute of Nuclear Physics (CINP) has put together a strategic report, following an extensive consultation process. The report describes the broad and ambitious research program undertaken by the Canadian nuclear physics research community, both onshore and abroad, touching on key questions regarding the origin, evolution, and structure of visible matter in the universe. This document provides a grid of different Canadian nuclear physics projects undertaken now and in the future, and their associated timelines. It concludes with specific recommendations for maximizing Canadian scientific output in nuclear physics.
↳ nucl-exastro-ph.SRhep-exnucl-th+11 citation
13
Confined and Deconfined Phases of Qubit Regularized Lattice Gauge Theories
Shailesh Chandrasekharan🇺🇸
We construct simple qubit-regularized Hamiltonian lattice gauge theories formulated in the monomer--dimer--tensor-network (MDTN) basis that are free of sign problems in the pure gauge sector. These models naturally realize both confined and deconfined phases. Using classical Monte Carlo methods, we investigate the associated finite-temperature phase transitions and show that they exhibit the expected universality classes of conventional SU(N) lattice gauge theories in various spacetime dimensions. Furthermore, we argue that second-order quantum phase transitions separating the confined and deconfined phases are likely to exist. Such critical points would provide a nonperturbative route to defining continuum limits of qubit-regularized gauge theories, potentially allowing Yang--Mills theory and related continuum gauge theories to emerge from finite-dimensional lattice constructions.
↳ hep-lathep-thnucl-th0 citations
14
Universality in spacetime $ω$ modes of quarkyonic stars
D. Dey🇮🇳 · Jeet Amrit Pattnaik🇮🇳 · R. N. Panda🇮🇳 · S. K. Patra🇮🇳
The gravitational wave $ω$ mode spectrum presents a unique window into the dense interior of neutron stars, probing physics inaccessible to electromagnetic observations. This work investigates the $ω$ modes of compact stars composed of quarkyonic matter. The quarkyonic model, which describes a cross-over transition between nucleonic and quark matter treated as quasi-particles, is formulated within the Relativistic Mean-Field (RMF) theory using the G3 and IOPB-I parameterizations. This core is surrounded by a mantle of hadronic matter, creating a multicomponent stellar interior. The overall Equation of State (EOS) is governed by two key parameters: the transition density ( $n_{t}$ ), the QCD confinement scale ( $Λ_{cs}$ ), which are varied to construct models consistent with current astrophysical constraints on mass and radius. We compute the complex eigenfrequencies (damped oscillations) of the fundamental and first excited $ω$ modes using the phase-amplitude method within a full general relativistic framework. Our simulations reveal that the admixed quarkyonic structure produces a unique $ω$ mode signature, distinctly different from pure hadronic or hybrid stars. The spectrum exhibits a strong, degenerate dependence on the EOS, where the stiffening effect of the quarkyonic matter influences oscillation frequencies and damping times in a characteristic manner. We also demonstrate that $ω$ mode frequencies for quarkyonic stars follow approximate universal relations, largely independent of the EOS.
↳ astro-ph.HEnucl-thPRD(2026)·0 citations
15
Form factors of the $ρ$ meson from effective field theory and the lattice
Ulf-G. Meißner🇩🇪 · Akaki Rusetsky🇩🇪 · Ajay S. Sakthivasan🇩🇪 · Gerrit Schierholz🇩🇪 · Jia-Jun Wu🇨🇳
The calculation of resonance form factors in effective field theory as well as on the lattice is a highly challenging task. In a recent paper, we proposed a novel method based on the introduction of a background field and the Feynman-Hellmann theorem to address the problem, and applied it to a toy model. In the present work we use this method for the electromagnetic form factors of the $ρ$ -meson. By matching the results to Chiral Perturbation Theory, we provide a first, crude estimate of all three form factors of the $ρ$ -meson within the effective field theory. Contact contributions to these form factors turn out to be substantial. A procedure for lattice calculations is outlined, paving the way for an ab initio approach to the problem.
↳ hep-lathep-phnucl-thJHEP(2026)·6 citations
16
Understanding the impact of nuclear effects on proton decay searches with the GiBUU model
Qiyu Yan🇨🇳 · Akira Takenaka · Kai Gallmeister🇩🇪 · Xianguo Lu🇬🇧 · Ulrich Mosel🇩🇪 · Yangheng Zheng🇨🇳
Proton decay searches in the next generation of water Cherenkov detectors, such as Hyper-Kamiokande, are expected to probe the $1 0^{35}$ -year lifetime regime where atmospheric neutrino backgrounds and systematic uncertainties begin to play an increasingly important role. In this study, we employ the GiBUU framework and reevaluate the proton decay search sensitivity for the $p \to e^{+} π^{0}$ channel by incorporating a typical event reconstruction performance in water Cherenkov detectors. Using sophisticated models implemented in GiBUU -- most notably the mean-field potential and Boltzmann transport -- which have been benchmarked against accelerator neutrino scattering data, in particular pion production, we find that the resulting proton decay signal detection efficiency and atmospheric neutrino background rate are comparable to those previously evaluated for the current and near future water Cherenkov experiments using $ad hoc$ nuclear models. In addition to pion final-state interactions, we evaluate the impact of differences in the Fermi momentum distribution of nucleons in the nucleus, as a source of systematic uncertainty, on the signal detection efficiency and the expected background event rate. We find that the uncertainty associated with pion final-state interactions is moderate, whereas the choice of Fermi momentum distribution can significantly affect the estimated atmospheric neutrino background rate and constitutes the dominant contribution. Our study provides an independent and complementary characterisation of nuclear effects on proton decay searches and helps to refine sensitivity estimates in the regime where systematic uncertainties become more relevant.
↳ hep-exnucl-exnucl-thPRD(2026)·1 citation
17
Universal and non-universal finite-volume effects in the vicinity of chiral phase transition in (2+1)-flavor QCD
Sabarnya Mitra🇩🇪 · Jishnu Goswami🇩🇪 · Frithjof Karsch🇩🇪
In this proceeding, we discuss the finite-size scaling analysis of the order parameter related to the chiral phase transition in QCD with two massless quarks. We use data obtained in lattice QCD calculations performed with highly improved staggered quarks (HISQ) for a range of light quark masses, $1/240 \leq m_{ℓ} / m_{s} \leq 1/27$ for different spatial volumes ( $N_{σ}$ ) on Euclidean lattices with temporal extent $N_{τ} = 8$ , satisfying $3 N_{τ} \leq N_{σ} \leq 10 N_{τ}$ . We observe that infinite volume extrapolated data for the order parameter agree reasonably well with the expected $O (2)$ scaling behavior even for physical ratios of the light-to-strange quark mass ratio. We quantify deviations from asymptotic scaling and perform a detailed analysis of the influence of finite-size effects in terms of temperature and quark masses at a fixed lattice cutoff. This is crucial for improving the reliability of the infinite-volume extrapolated estimate of the chiral order parameter and for a more precise determination of chiral phase transition temperature from direct Lattice QCD simulations.
↳ hep-lathep-phhep-thnucl-ex+12 citations

Affiliations

first authorsco-authorsvia INSPIRE