Nuclear Theory·nucl-th

Tuesday·June 16, 2026

14 papers—3 primary·11 cross-listed

04
[Submitted on 11 Jun 2026] (cross-list from nucl-ex)
Experimental exploration of the QCD phase diagram
A. Andronic🇩🇪 · P. Braun-Munzinger🇩🇪 · K. Redlich🇵🇱 · J. Stachel🇩🇪
The different phases of strongly interacting matter are governed by Quantum Chromodynamics (QCD). At high temperature and/or density a deconfined, chirally symmetric phase of quarks and gluons is expected to govern the nature of strongly interacting matter, the so-called quark-gluon plasma. Here we review what is known about the existence of this exotic form of matter from an experimental point of view and confront the results with QCD predictions based on 'Lattice QCD', where QCD is discretized on a space-time lattice and solved numerically in a Monte Carlo approach. The form of the presentation is explicitly pedagogical but the results include even very recent developments. Our research is based on the interpretation of hadron production data from relativistic nucleus--nucleus collisions over a wide energy range, with the aim to make progress in the understanding of the QCD phase, and of phenomena like deconfinement and hadronization.
Comments:
17 pages, 8 Figs; chapter for Encyclopedia of Nuclear Physics
Subjects:
Nuclear Experiment (nucl-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2606.14799 [pdf]
0 citations
05
[Submitted on 12 Jun 2026] (cross-list from hep-ph)
Towards a consistent perturbation theory at finite temperature
Passant Ali🇩🇪 · Peter Lowdon🇩🇪 · Owe Philipsen🇩🇪
The standard approach to perturbation theory for finite-temperature quantum field theories has several issues, including the appearance of ill-defined on-shell contributions in the real-time formulation, and infrared diverges in massless theories. Earlier studies indicate that these issues all stem from the inconsistent thermal generalisation of the Gell-Mann-Low relation, which forms the foundation of perturbation theory in vacuum. This inconsistency arises from the use of free scattering states in the relation, which are known not to exist in interacting thermal theories. In this work, we propose a generalisation of the Gell-Mann-Low relation for scalar theories based on non-perturbative spectral insights, namely that finite-temperature scattering states can be described by damped but stable particle-like excitations, so-called thermoparticles. The perturbative expansion of this generalised relation gives rise to contributions with exactly the same topology as the standard finite-temperature approach, except that now the propagators appearing in this expansion are not those of a free field but of thermoparticles, which depend on the dynamics of the theory. We demonstrate that thermoparticle perturbation theory resolves the known problems of the standard approach. Furthermore, by comparing imaginary-time calculations at two-loop level with numerical lattice simulations of two-point correlation functions in massive $ϕ^{4}$ theory, we explicitly show that this framework gives rise to precise predictions, as in the vacuum case, in stark contrast to the standard approach.
Comments:
31 pages, 8 figures; Figure data attached
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2606.14863 [pdf]
1 citation
06
[Submitted on 14 Jun 2026] (cross-list from hep-ph)
Production of high-orbital kaon excited states in the $K^{-} p$ reaction
Ting-Yan Li🇨🇳 · Zi-Yue Bai🇨🇳 · Xiang Liu🇨🇳
In this work, a systematic investigation of the production of high-orbital-excitation kaons in $K^{-} p$ reactions is carried out within an effective Lagrangian approach. The relevant $t$ -channel processes are constructed, and the model is calibrated using a single adjustable parameter determined from existing experimental data. With this parameter, the measured production cross sections for the $K_{3}^{*} (1780)$ , $K_{2} (1820)$ , $K_{2} (1770)$ and $K_{4}^{*} (2045)$ states are successfully reproduced. Employing the same framework, the production cross sections for other high-orbital kaons are predicted. The results indicate that these states possess sizable cross sections and exhibit characteristically forward-peaked angular distributions, which is a typical feature of $t$ -channel exchange, highlighting their great potential for observation in future experiments.
Comments:
15 pages, 8 figures and 2 tables. More references added and some typos corrected
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2606.15736 [pdf]
PRD(2026)·0 citations
07
[Submitted on 14 Jun 2026] (cross-list from hep-ph)
Why fluctuations of conserved charges in the confining regime above $T_{c h}$ behave as if the quarks were free?
L. Ya. Glozman
Some cumulants of the fluctuations of conserved charges soon above the chiral crossover behave as if the quarks were free. This was taken by many as evidence of deconfinement. At the same temperatures the mesonic correlators reveal the chiral spin and SU(4) symmetries, indicating that the propagating degrees of freedom are massless quarks connected into color singlets by the chromoelectric confining string. These correlators are qualitatively different from the free quark gas. Here we clarify the reason for the difference. The conserved quark number densities do not propagate in time but do propagate in spatial directions. The mesonic propagators calculated in full QCD differ radically from the free quark loop (quark gas) above T_ch. In contrast, the quark number density spatial propagator in full QCD at T > 220 MeV is very close to the free quark loop. In other words, the conserved charges do not see confinement, in contrast to the mesonic correlators. This is consistent with the well understood quark-hadron duality at T=0 in e^+e^- -> hadrons, where at invariant masses above 2 GeV the cross-section in the confining regime is represented by the free quark loop plus small perturbative corrections. All these features above T_ch but below the deconfinement temperature T_d can be combined within the following microscopic picture of the stringy fluid matter. It is a medium of the overlapping strongly interacting color singlet clusters. The quark interchanges between the clusters, required by Paili principle, make the quarks quasifree, which is reflected in fluctuations of conserved charges.
Comments:
7 pages
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); High Energy Physics — Lattice (hep-lat); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2606.15798 [pdf]
2 citations
08
[Submitted on 14 Jun 2026] (cross-list from cond-mat.quant-gas)
Asymmetric binary Bose mixtures: a Functional Renormalisation Group study
Boris Krippa
Zero-temperature binary Bose mixtures with mass and intraspecies couplings imbalances are studied using the functional renormalisation group (FRG) framework. We find that this dual asymmetry induces a spontaneous redistribution of quantum fluctuations between the components. This effect leads to a significant divergence in the quasiparticle residues of the two species, a phenomenon not captured in mean-field treatments. Critically, our FRG analysis predicts a systematic reduction of the density-channel sound velocity with increasing asymmetry -- a result that qualitatively contradicts the behaviour predicted by standard Bogoliubov theory. The ratio of the renormalisation factors is proposed as a robust quantitative probe of many-body correlations and fluctuation transfer. These findings provide a consistent non-perturbative framework for interpreting future experiments on heterogeneous mixtures.
Comments:
20 pages, 10 figures
Subjects:
Quantum Gases (cond-mat.quant-gas); Nuclear Theory (nucl-th)
arXiv:
2606.16029 [pdf]
0 citations
09
[Submitted on 15 Jun 2026] (cross-list from physics.plasm-ph)
Quasiparticles and ion cooling by an electron beam in a strong magnetic field
D.M.Popov · A.I.Milstein
The frictional force arising from the interaction of ions with a magnetized electron beam in a strong magnetic field is investigated. The problem is reduced to the interaction of quasiparticles, or Larmor circles, with ions. A Hamiltonian describing this interaction is derived. The role of various impact parameters in the process of ion cooling is elucidated. The cases of both positively and negatively charged ions are considered.
Comments:
13 pages, 14 figures
Subjects:
Plasma Physics (physics.plasm-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th); Accelerator Physics (physics.acc-ph)
arXiv:
2606.16126 [pdf]
0 citations
10
[Submitted on 15 Jun 2026] (cross-list from hep-ph)
Static linear response of hot and dense QCD matter to electromagnetic fields: Leading hard and soft QCD corrections
Osvaldo Ferreira🇧🇷 · Eduardo S. Fraga🇧🇷 · Tyler Gorda🇺🇸 · Risto Paatelainen🇫🇮 · Leon Sandbote🇫🇮 · Kaapo Seppänen🇨🇭
We compute the static electromagnetic susceptibilities of a hot and dense quark-gluon plasma using perturbative Quantum Chromodynamics (QCD). Our evaluation includes the leading $O (α_{s})$ correction as well as the leading soft, resummed contribution of $O (α_{s}^{3/2})$ within electrostatic QCD. By matching to Lattice QCD at vanishing baryon chemical potential through Lattice perturbation theory, we establish a connection between perturbative results and Lattice simulations and assess the size of higher-order corrections. This extends the electromagnetic susceptibilities to finite baryon chemical potential, where Lattice methods are not applicable and establishes first-principle constraints on the quark-gluon plasma's electromagnetic response at temperatures and densities relevant for intermediate-energy heavy-ion collisions.
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2606.16377 [pdf]
0 citations
11
[Submitted on 15 Jun 2026] (cross-list from hep-ph)
Diffractive structure functions from JIMWLK evolution
Tuomas Lappi · Heikki Mäntysaari · Pyry Runko
We compute diffractive structure functions from Wilson line configurations whose energy evolution is given by the JIMWLK equation. We use a JIMWLK evolution setup that has already been constrained with exclusive vector meson production data from HERA. We compare our results to HERA measurements and also extended to heavy nuclei. In particular we can calculate predictions for the nuclear modification factor and diffractive-to-total cross section ratios at the EIC.
Comments:
7 pages, 4 figures, talk by PR at the DIS 2026 conference
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2606.16705 [pdf]
0 citations
12
[Submitted on 15 Jun 2026] (cross-list from hep-lat)
Direct calculation of parton distributions in momentum space from lattice QCD
Anthony V. Grebe🇺🇸 · Daniel C. Hackett🇺🇸 · Michael L. Wagman🇺🇸 · Rui Zhang🇺🇸 · Yong Zhao🇺🇸
Coulomb-gauge quasi-parton distributions can be computed directly in momentum space on a finite lattice, enabled by the commutativity of their renormalization and Fourier transform. This approach removes the formal inverse problem in coordinate-space methods. Our momentum-space pion quasi-distributions agree with coordinate-space results Fourier transformed with asymptotic extrapolation, indicating that the formal inverse problem in the latter is not a concern at this volume. We further extend the framework to higher dimensions and obtain the first 3D image of the pion directly from lattice QCD.
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2606.16877 [pdf]
2 citations
13
[Submitted on 15 Jun 2026] (cross-list from hep-ph)
Spin-Selective Hadron Spectroscopy via Azimuthal Anisotropies from Entanglement-Enabled Spin Interference
Samuel Corey🇺🇸 · James Daniel Brandenburg🇺🇸
The $π^{+} π^{-}$ invariant mass spectrum above the $ρ^{0} (770)$ is rich with broad, overlapping resonances. Disentangling them, whether in photoproduction, ultra-peripheral heavy-ion collisions, or electroproduction, is a longstanding challenge for conventional partial-wave analysis. We show that the recently observed entanglement-enabled spin-interference effect in ultra-peripheral collisions provides a quantum-mechanical filter that resolves this ambiguity: the angular harmonics $A_{n}$ of the $cos (n Δ ϕ)$ asymmetry, which are governed by selection rules in the spin of the interfering states. Specifically, overlap between two distinct spin-1 amplitudes leads to interference that populate $A_{2}$ alone, while overlap of a spin-1 amplitude with a spin-2 one generates $A_{1}$ and $A_{3}$ . Utilizing ALICE data in the $1.0$ -- $1.4 GeV c^{- 2}$ region, we demonstrate that two physically distinct hypotheses -- an additional spin-1 $ρ^{'} (1450)$ (produced via photonuclear interactions) versus a spin-2 (photon-photon) $f_{2} (1270)$ state -- fit the invariant mass spectrum equally well but predict different $A_{n}$ : identically zero $A_{1}$ and $A_{3}$ in the spin-1 case, versus pronounced peaks in the spin-2 case. This selection rule provides a new tool for hadronic spectroscopy in ultra-peripheral collisions and the first viable route to isolating the $γ γ \to π^{+} π^{-}$ continuum from the dominant photonuclear background, revealing a clean low-energy probe of non-perturbative QCD.
Comments:
5 pages
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2606.16966 [pdf]
0 citations
14
[Submitted on 15 Jun 2026] (cross-list from hep-ph)
Hadronic tensor in lattice gauge theories by quantum computing
Dairui Zou🇨🇳 · Tianyin Li🇯🇵 · Jian Liang🇨🇳 · Enke Wang🇨🇳 · Hongxi Xing🇨🇳
The hadronic tensor encodes crucial information regarding the internal structure of hadrons, reflecting the non-perturbative features of quantum chromodynamics (QCD). In this work, we directly compute the hadronic tensor within (1+1)-dimensional $U (1)$ and $SU (2)$ gauge theories by evaluating real-time current-current correlation functions. Utilizing quantum algorithms executed on classical hardware, we demonstrate that the hadron form factors for both meson and baryon states can be reliably extracted from the hadronic tensor. Our methodology is validated by strong agreement with both direct calculation and exact diagonalization of the form factors.
Comments:
9 pages, 7 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2606.17003 [pdf]
2 citations

Affiliations

first authorsco-authorsvia INSPIRE