Nuclear Theory·nucl-th

Tuesday·December 30, 2025

20 papers—12 primary·8 cross-listed

13
[Submitted on 15 Dec 2025] (cross-list from cond-mat.other)
Anomalous Transport In Low Dimension Materials
Leonardo Lopes
This dissertation presents a systematic theoretical investigation into realizing a condensed matter analogue of the Chiral Magnetic Effect (CME) in a quasi-planar, 2+1D system. The research establishes a conceptual bridge between the anomalous transport phenomena of high-energy physics and the emergent electronic properties of engineered honeycomb lattices. The central objective is the formulation of a low-energy effective Hamiltonian that incorporates the necessary ingredients for a CME-like effect. This is achieved by moving beyond pristine graphene, whose inherent sublattice symmetry precludes the formation of a mass gap necessary for defining robust pseudo-chiral states. The core of this work is a model based on a honeycomb lattice with explicitly broken sublattice symmetry, which introduces a band gap and endows the quasi-particles system with a well-defined pseudo-chirality based on sublattice polarization. A time-reversal symmetry-breaking parameter is introduced to asymmetrically modify the valley gaps, creating a controllable non-equilibrium imbalance analogous to the chiral chemical potential in relativistic systems. A key finding is the validation of the physical model consistency; through commutator calculations, the total angular momentum - comprising both orbital and an emergent lattice spin component - is shown to be a conserved quantity. This research successfully transforms the abstract possibility of a 2D CME into a concrete, self-consistent theoretical framework, detailing the precise symmetry conditions required for its manifestation.
Comments:
Master's thesis, 69 pages, 18 figures
Subjects:
cond-mat.other (cond-mat.other); Mesoscale and Nanoscale Physics (cond-mat.mes-hall); High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2512.22155 [pdf]
0 citations
14
[Submitted on 26 Dec 2025] (cross-list from hep-ph)
Orbital angular momentum in the pion and kaon: rest-frame and light-front
Y.-Y. Xiao🇨🇳 · Z.-N. Xu🇪🇸 · Z.-Q. Yao🇩🇪 · C. D. Roberts🇨🇳 · J. Rodríguez-Quintero🇪🇸
Orbital angular momentum (OAM) is not a Poincaré invariant quantity; so, its value is observer dependent. Notwithstanding that, in quantum chromodynamics, a Poincaré-invariant theory, OAM is part of every hadron wave function. Using continuum Schwinger function methods, we elucidate both the subjective character of in-hadron OAM and expose some of its impacts on pion and kaon structure and observables. For instance, working with light-front projections of their Bethe-Salpeter wave functions, it is found that the pion is a roughly 50/50 mix of light-front OAM zero and one components and the kaon is a 60/40 system. The overall picture is that (near) Nambu-Goldstone modes are complex bound states, each with significant intrinsic OAM, independent of the observer's reference frame. This feature must be accounted for in the calculation of observables. Inductively, the same is true for all hadrons.
Comments:
10 pages, 4 figures, 3 tables. Version accepted by Phys. Lett. B
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2512.22359 [pdf]
PLB(2026)·4 citations
15
[Submitted on 26 Dec 2025] (cross-list from hep-ph)
Nonequilibrium QCD in heavy-ion collisions: Kinetic theory and jet modifications during the initial stages
Florian Lindenbauer🇦🇹
This thesis focuses on how jets are modified by the nonequilibrium quark-gluon plasma during the initial stages in heavy-ion collisions. Its influence on their propagation is typically encoded in a single medium function, the dipole cross section. Its small distance behavior is characterized by the jet quenching parameter $q^$ , and we obtain its numerical value throughout the pre-equilibrium stage, finding values comparable in magnitude to the earlier Glasma stage. We also compute the more general elastic collision kernel, obtained by Fourier transforming the dipole cross section. This constitutes an important step to facilitate the understanding of jet-medium interactions during the initial stages in heavy-ion collisions. Additionally, we improve QCD kinetic theory simulations by employing a more realistic (HTL) screening mechanism to incorporate medium effects, which we compare with simpler screening mechanisms. An expanding plasma realized in the initial stages of heavy-ion collisions exhibits a significantly reduced maximum anisotropy and reduced specific shear viscosity $η / s$ when using the improved screening prescription. Moreover, we investigate the gluon splitting rates, which are typically obtained using an isotropic model for the collision kernel. Going beyond that approximation, we find that the splitting rates obtained from the nonequilibrium anisotropic kernel differ significantly both in magnitude and in their qualitative time evolution. We further identify a novel type of weak-coupling attractor, which can be observed in the ratio of the jet quenching parameter and pressure ratio, and is obtained by extrapolating to vanishing coupling. This improved kinetic theory description and novel limiting attractors contribute towards a more realistic modeling of the nonequilibrium QCD plasma and its equilibration and hydrodynamization process during the initial stages.
Comments:
PhD thesis, 230 pages, 62 figures, based on arXiv:2303.12595, arXiv:2312.00447, arXiv:2312.11252, arXiv:2407.09605, arXiv:2509.03868, arXiv:2509.09897, abstract shortened to comply with arXiv guidelines
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2512.22384 [pdf]
0 citations
16
[Submitted on 27 Dec 2025] (cross-list from hep-ph)
Quark Coalescence: Formation of Mesons Including Excited States
R. J. Fries · P. Virupapuram · J. Purcell · H. Anconetani · W. Lippincott · S. Robicheaux · M. Kordell · C. M. Ko
We discuss the quantum mechanics of coalescence of quark-antiquark pairs into mesons using a non-relativistic quark model. We derive the coalescence probabilities assuming a harmonic oscillator potential and generic Gaussian wave packet shapes for the initial quarks and antiquarks. Our particular emphasis is on modeling excited states of the meson spectrum consistently. We provide the formalism to systematically include excited states from the Particle Data Book, and many more predicted by the quark model, up to $L = 4$ and masses of about 2.2 GeV for light flavors. We provide estimates of masses and decay branching ratios for unconfirmed states. We use a phase space picture which is appropriate for the quasi-classical nature of the information typically available for the quarks and antiquarks in applications like Monte Carlo simulations. We demonstrate that for typical parton configurations expected in jets, excited meson states are populated abundantly.
Comments:
17 pages, 8 figures, 6 large tables
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2512.22465 [pdf]
1 citation
17
[Submitted on 29 Dec 2025] (cross-list from hep-ph)
Fine-tuning final state interactions model in NuWro Monte Carlo event generator
Hemant Prasad🇵🇱 · Jan T. Sobczyk🇵🇱 · Rwik Dharmapal Banerjee🇵🇱 · J. Luis Bonilla🇵🇱 · Krzysztof M. Graczyk🇵🇱 · Beata E. Kowal🇵🇱 · Artur M. Ankowski🇵🇱
Recent experimental data from MINERvA on transverse kinematics observables across four different nuclear targets - carbon, oxygen, iron, and lead - have been utilized to refine the modeling of final state interaction effects in the NuWro Monte Carlo neutrino event generator. For this purpose, we have developed an event reweighting tool for future applications to adjust the strength of final-state interactions. This study highlights the requirement for stronger nucleon reinteractions than previously assumed, but it still falls within the uncertainty range observed in a study comparing proton transparency measurements. This conclusion has significant implications for both experimental and theoretical work involving NuWro.
Comments:
17 pages, 14 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2512.23350 [pdf]
PRD(2026)·1 citation
18
[Submitted on 29 Dec 2025] (cross-list from hep-ph)
Perturbative results for the matrix elements of the vector current and the role of different infrared regulators
Alessio Carmelo Alvaro🇮🇹 · Ignacio Castelli🇺🇸 · Cédric Lorcé🇫🇷 · Andreas Metz🇺🇸 · Barbara Pasquini🇮🇹 · Simone Rodini🇮🇹
We investigate the twist-2 unpolarized generalized parton distributions (GPDs) of quarks for an on-shell gluon target in quantum chromodynamics. These GPDs parametrize the leading-twist matrix elements of the nonlocal light-like flavor-singlet vector current. We compute them at one-loop accuracy in perturbation theory using a quark mass and dimensional regularization as infrared regulators. In particular, we discuss the limit of vanishing momentum transfer. The present work extends our previous related study on the axial current.
Comments:
9 pages, 1 figure
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2512.23563 [pdf]
PLB(2026)·0 citations
19
[Submitted on 29 Dec 2025] (cross-list from astro-ph.HE)
Limits on dark matter existence in neutron stars from recent astrophysical observations and mass correlation analysis
Jing Fu Hu · Hang Lu · Bao Yuan Sun
Dark matter admixed neutron stars (DANSs) serve as a specific astrophysical laboratory for probing the features of dark matter (DM) and have emerged as a promising candidate for interpreting recent astrophysical observations (e.g., by NICER and LIGO/Virgo). Accurately constraining the internal DM content of DANSs is therefore of critical importance. In this work, we construct the equations of state (EoS) for DANS matter by employing twelve nuclear matter (NM) models within the covariant density functional (CDF) theory and a self-interacting fermionic model for DM. Using these EoSs as input, we solve the two-fluid Tolman-Oppenheimer-Volkov (TOV) equations to systematically investigate the influence of DM on the global properties of neutron stars (NSs). By incorporating recent observational constraints on NS properties, the maximum DM mass fraction $f_{χ}^{max}$ in DANSs is determined for each NM EoS model. Our analysis reveals a strong linear correlation (Pearson coefficient $r = 0.98$ ) between $f_{χ}^{max}$ and the maximum mass of a pure NS, $M_{NS}^{max}$ , described by $f_{χ}^{max} = 0.22 M_{NS}^{max} - 0.44$ . Leveraging this correlation and the observed NS maximum mass distribution, $P (M_{NS}^{m a x} ∣ EM)$ , we derive the probability distribution function (PDF) for the maximum DM mass, $P (M_{χ}^{m a x} ∣ EM)$ , in DANSs. We find that at the 68\% confidence level, $M_{χ}^{max} = 0.15 0_{- 0.051}^{+ 0.070} M_{⊙}$ . This quantitative constraint on the DM mass provides a critical prior for interpreting potential observational signatures of DANSs, such as anomalous tidal deformabilities and distinctive gravitational-wave signals.
Comments:
12 pages, 5 figures, 1 table
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); Nuclear Theory (nucl-th)
arXiv:
2512.23577 [pdf]
Astrophys.Space Sci.(2026)·1 citation
20
[Submitted on 29 Dec 2025] (cross-list from hep-ph)
The Effect of Hadronic Matter on Parton Energy Loss
Ritoban Datta🇺🇸 · Abhijit Majumder🇺🇸
Modified thermal distributions (dispersion relations) are introduced within both the MATTER and LBT event generators used to describe jet modification in a heavy-ion collision, within the JETSCAPE framework. Hard partons, propagating through dense matter, scatter off the partonic substructure of the medium, leading to stimulated emission, accompanied by recoiling medium partons. We introduce a simple modification, a multiplicative $(1 + a / T)$ correction to the dispersion relation of quarks and gluons (equivalent to an effective fugacity). This leads to calculated transport coefficients (e.g. $q^/ T^{3}$ ) showing the expected behavior of depreciating at lower temperatures, including within the hot hadronic gas. This simple modification recovers the light-like dispersion relations at high temperatures, and introduces an excess depreciation factor for parton populations at lower temperatures, allowing partonic energy loss and recoil calculations to be extended into the hadronic phase. This modified distribution, in combination with initial state cold nuclear matter effects (shadowing), is used to simultaneously describe the nuclear modification factor and elliptic anisotropy of jets and leading hadrons, over multiple centralities and collision energies.
Comments:
- Typos corrected; link to the JETSCAPE package added
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2512.23692 [pdf]
2 citations

Affiliations

first authorsco-authorsvia INSPIRE