Nuclear Theory·nucl-th

Monday·July 21, 2025

14 papers—4 primary·10 cross-listed

05
Observation of a dynamic magneto-chiral instability in photoexcited tellurium
Yijing Huang · Nick Abboud · Yinchuan Lv · Penghao Zhu · Azel Murzabekova · Changjun Lee · Emma A. Pappas · Dominic Petruzzi · Jason Y. Yan · Dipanjan Chauduri · Peter Abbamonte · Daniel P. Shoemaker and 3 other authors
In a system of charged chiral fermions driven out of equilibrium, an electric current parallel to the magnetic field can generate a dynamic instability by which electromagnetic waves become amplified. Whether a similar instability can occur in chiral solid-state systems remains an open question. Using time-domain terahertz (THz) emission spectroscopy, we detect signatures of what we dub a ``dynamic magneto-chiral instability" in elemental tellurium, a structurally chiral crystal. Upon transient photoexcitation in a moderate external magnetic field, tellurium emits THz radiation consisting of coherent modes that amplify over time. An explanation for this amplification is proposed using a theoretical model based on a dynamic instability of electromagnetic waves interacting with infrared-active oscillators of impurity acceptor states in tellurium to form an amplifying polariton. Our work not only uncovers the presence of a magneto-chiral instability but also highlights its promise for THz-wave amplification in chiral materials.
↳ cond-mat.mes-hallcond-mat.dis-nncond-mat.stat-mechhep-ph+1Nat.Phys.(2026)·0 citations
06
Quark + Diquark Description of Nucleon Elastic Electromagnetic Form Factors
Peng Cheng🇨🇳 · Zhao Qian Yao🇪🇸 · Daniele Binosi🇪🇸 · Ya Lu🇨🇳 · Craig D. Roberts🇨🇳
Working with a Poincaré-covariant quark + diquark, $q (q q)$ , Faddeev equation approach to nucleon structure, a refined symmetry preserving current for electron + nucleon elastic scattering is developed. The parameters in the interaction current are chosen to ensure that the $q (q q)$ picture reproduces selected results from contemporary $3$ -body analyses of nucleon elastic electromagnetic form factors. Although the subset of fitted results is small, the $q (q q)$ picture reproduces almost all the $3$ -body predictions and often results in better agreement with available data. Notably, the $q (q q)$ framework predicts a zero in $G_{E}^{p} / G_{M}^{p}$ , the absence of such a zero in $G_{E}^{n} / G_{M}^{n}$ , and a zero in the proton's $d$ -quark Dirac form factor. Derived $q (q q)$ results for proton flavour-separated light-front-transverse number and anomalous magnetisation densities are also discussed. With the $q (q q)$ framework thus newly benchmarked, one may proceed to comparisons with a broader array of $3$ -body results. This may enable new steps to be made toward answering an important question, viz. is the quark + fully-interacting diquark picture of baryon structure only a useful phenomenology or does it come close to expressing robust features of baryon structure?
↳ hep-phhep-exhep-latnucl-ex+1EPJA(2025)·8 citations
07
The equation of state and surface tension of QCD in the first order phase transition region
Yuan-jun Mei🇨🇳 · Yi Lu🇨🇳 · Fei Gao🇨🇳 · Yu-xin Liu🇨🇳
We build up a complete description of QCD phase structure by applying the parametrization of the chiral and deconfinement order parameters upon the calculations from functional QCD approaches. In particular in the first order phase transition region at high chemical potential, both the phase transition line using Maxwell construction and the coexistence boundary lines from the spinodal decompostion are determined. We compute the thermodynamic quantities including the number density, the energy density, the pressure and also the free energy for both stable and unstable phases of QCD. Additionally, after applying a phenomenological description of the inhomogeneity of the QCD free energy, we obtain the surface tension of the first order phase transition of QCD.
↳ hep-phhep-thnucl-exnucl-thPRD(2026)·3 citations
08
Triply heavy tetraquarks $b ˉ c q ˉ c$ and $c ˉ b q ˉ b$ in a constituent quark model
Gang Yang🇨🇳 · Jialun Ping🇨🇳 · Jorge Segovia🇪🇸
A systematic investigation of $S$ -wave triply heavy tetraquark systems with quark content $b ˉ c q ˉ c$ and $c ˉ b q ˉ b$ $(q = u, d, s)$ , spin-parity quantum numbers $J^{P} = 0^{+}$ , $1^{+}$ , $2^{+}$ and isospin $I = 0, \frac{1}{2}$ , is carried out within the constituent quark model framework. The four-body bound and resonance states are determined by solving the Schrödinger equation employing the high-precision and efficient Gaussian Expansion Method (GEM) in conjunction with the powerful Complex Scaling Method (CSM). Besides, a comprehensive coupled-channel analysis of the $S$ -wave tetraquark systems is performed, taking into account meson-meson, diquark-antidiquark and K-type configurations, as well as all allowed color structures. Several narrow resonant states are identified in each $I (J^{P})$ channel. In particular, resonances for the $b ˉ c q ˉ c$ system are found in the mass range of $8.87 - 9.36$ GeV, while those for the $c ˉ b q ˉ b$ system lie between $12.13 - 12.45$ GeV. Most of the predicted resonances are compact tetraquark states with sizes smaller than $1.0$ fm, although four states exhibit more extended structures with sizes around $1.3$ fm, suggesting a more loosely bound nature. Magnetic moments and dominant wave function components of these exotic states are also analyzed. The results indicate that K-type configurations play a major role in the structure of the observed resonances. Finally, possible strong decay channels (golden modes) for these states are theoretically proposed.
↳ hep-phhep-exhep-latnucl-ex+1PRD(2026)·4 citations
09
Strangeon Matter: from Stars to Nuggets
Haoyang Qi🇨🇳 · Renxin Xu🇨🇳
The fact that strange sea quarks are abundant in the nucleons, but with zero net strangeness, is of great importance for understanding the nature of matter condensed by the strong interaction, particularly in the context of the ``gigantic nucleus'' formed by the gravitational collapse of an evolved massive star. We hypothesize that the basic unit of bulk strong matter with the light-flavor symmetry of valence quarks is ``strangeon'', which is the counterpart of the nucleon found in atomic nuclei. In addition to strangeon stars (SnSs) with large baryon number of $A \approx 1 0^{57}$ , strange nuggets (SnNs) with $A ≳ 1 0^{10}$ could also exist in the Universe. Both the SnS and the SnN are explained, with attention to their observational evidence.
↳ astro-ph.HEhep-phnucl-thUniverse(2025)·1 citation
10
Neutron emission associated with $γ γ \to γ γ$ scattering in UPC of heavy ions at the LHC
Pawel Jucha🇵🇱 · Mariola Klusek-Gawenda🇵🇱 · Antoni Szczurek🇵🇱
We calculate cross sections for the production of different neutron classes $0 n 0 n$ , $0 n X n + X n 0 n$ and $X n X n$ , possible to measure in Zero Degree Calorimeters (ZDCs), associated with photon-photon scattering in UPC of lead on lead. The calculations are performed for the ATLAS kinematics. Our calculations for neutron classes are tested against existing data for $ρ^{0}$ production in UPC. We get a good agreement for absolute cross section as well as very good results for fractional cross section which gives confidence to the analogous calculation for diphoton production, corresponding to $γ γ \to γ γ$ scattering. We present both absolute as well as fractional cross sections for the different neutron classes. We also show different distributions in impact parameter, photon rapidity, transverse momentum, diphoton invariant mass and photon rapidity difference. The shapes of the photon distributions depend on the neutron classes which we quantify in this paper. It would be valuable to test our predictions using the ATLAS main detector and the ATLAS ZDCs.
↳ hep-phnucl-thPRD(2025)·4 citations
11
Anomalous-magnetic-moment-enhanced Casimir effect
Daisuke Fujii🇯🇵 · Katsumasa Nakayama🇯🇵 · Kei Suzuki🇯🇵
We theoretically investigate the impact of the anomalous magnetic moment (AMM) of Dirac fermions on the fermionic Casimir effect under magnetic fields. We formulate it as an extension of the well-known Lifshitz formula. From our formula, we find that the AMM increases the fermionic Casimir energy. In particular, when the AMM is large enough, the Casimir energy is significantly enhanced by the gapless behavior of the lowest Landau level. We also quantitatively estimate the Casimir energy from electron, muon, and constituent quark fields under magnetic fields and propose possible phenomena at finite temperature and fermion density.
↳ hep-phhep-thnucl-thquant-phPRD(2026)·1 citation
12
Deep Image Reconstruction for Background Subtraction in Heavy-Ion Collisions
Umar Sohail Qureshi🇺🇸 · Raghav Kunnawalkam Elayavalli🇺🇸
Jet reconstruction in an ultra-relativistic heavy-ion collision suffers from a notoriously large, fluctuating thermal background. Traditional background subtraction methods struggle to remove this soft background while preserving the jet's hard substructure. In this Letter, we present DeepSub, the first machine learning-based approach for full-event background subtraction. DeepSub utilizes a model based on Swin Transformer layers to denoise jet images and disentangle hard jets from the heavy-ion background. DeepSub significantly outperforms existing subtraction techniques by reproducing key jet observables such as jet $p_{T}$ and mass, and substructure observables such as girth and the energy correlation function, at the sub-percent to percent level. As such, DeepSub paves the way for precision heavy-ion measurements in hitherto inaccessible kinematic regimes.
↳ hep-phnucl-exnucl-thphysics.data-anPRC(2025)·4 citations
13
Global Bayesian Analysis of $J / ψ$ Photoproduction on Proton and Lead Targets
Heikki Mäntysaari🇫🇮 · Hendrik Roch🇺🇸 · Farid Salazar🇺🇸 · Björn Schenke🇺🇸 · Chun Shen🇺🇸 · Wenbin Zhao🇺🇸
We perform a global Bayesian analysis of diffractive $J / ψ$ production in $γ + p$ and $γ + Pb$ collisions using a color glass condensate (CGC) based calculation framework. As past calculations have shown that CGC-based models typically overpredict the $J / ψ$ production in $γ + Pb$ collisions at high center of mass energy, we address the question of whether it is possible to describe coherent and incoherent diffractive $J / ψ$ data from $γ + p$ collisions at HERA and the LHC, and from $γ + Pb$ collisions at the LHC simultaneously. Our results indicate that a simultaneous description of $γ + p$ and $γ + Pb$ data is challenging, with results improving when an overall $K$ -factor -- scaling $γ + p$ and $γ + Pb$ cross sections to absorb model uncertainties -- is introduced.
↳ hep-phnucl-thPRD(2026)·21 citations
14
Symmetrizing relativistic three-body partial wave amplitudes
Andrew W. Jackura🇺🇸 · Nicholas C. Chambers🇺🇸 · Raúl A. Briceño🇺🇸
S matrix principles and symmetries impose constraints on three-particle scattering amplitudes, which can be formulated as a class of integral equations for their partial wave projections. However, these amplitudes are typically expressed in an asymmetric basis, where one of the initial and final state particles is singled out, and all quantum numbers are defined relative to this spectator. In this work, we show how to construct symmetric partial wave amplitudes, which have been symmetrized over all possible spectator combinations, using their asymmetric counterparts and sets of recoupling coefficients. We derive these recoupling coefficients for arbitrary angular momentum and isospin for arbitrary systems of spinless particles with SU(2) flavor symmetry. We propose a simple intensity observable suitable for visualizing the structure of three-body dynamics in Dalitz distributions. Finally, we provide some numerical examples of Dalitz distributions relevant for future lattice QCD calculations of $3 π$ systems and provide numerical evidence that the symmetrization procedure is consistent with expected symmetries of Dalitz plots.
↳ hep-phhep-lathep-thnucl-thPRD(2026)·5 citations

Affiliations

first authorsco-authorsvia INSPIRE