Nuclear Theory·nucl-th

Tuesday·March 3, 2026

19 papers—11 primary·8 cross-listed

12
[Submitted on 27 Feb 2026] (cross-list from hep-ph)
An EFT approach to Color decoherence in jet quenching
Varun Vaidya🇺🇸
We use the EFT developed in \cite{Mehtar-Tani:2025xxd}, to understand the interference driven phenomenon of color decoherence in inclusive jet production in a dense nuclear medium such as Nuclei or Quark Gluon Plasma. Using the factorization formula in \cite{Mehtar-Tani:2024smp,Mehtar-Tani:2025xxd}, expressed as a series of multi-sub-jet operators, we define and calculate the contribution of the two sub-jet effective operator. This explicitly reveals the emergent angular scale $θ_{c}$ that controls color decoherence as well an intricate renormalization group structure for the factorized functions. We show that for a jet of radius R in a medium of size L characterized by a jet quenching parameter $q^$ , both the LPM effect and color decoherence are controlled by a single dimensionless parameter $q^L L R$ and therefore are equally important for phenomenology. This paper shows how interference driven emergent effects can be included in a factorized framework for computing jet observables in heavy ion collisions.
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2603.00238 [pdf]
5 citations
13
[Submitted on 27 Feb 2026] (cross-list from nucl-ex)
Physics Opportunities with a Fixed-Target Program at the Electron-Ion Collider
C.-J. Naïm🇺🇸 · A. Sorensen🇺🇸 · D. Brown🇺🇸 · D. Cebra🇺🇸 · R. Corliss🇺🇸 · J. M. Durham🇺🇸 · R. Vogt🇺🇸
A fixed-target program at the Electron-Ion Collider (EIC) would broaden the facility's scientific reach by providing key measurements for studies of cold nuclear matter (CNM), the QCD phase diagram, and nuclear reactions relevant for space radiation. Constraining CNM effects is essential for interpreting observables in proton-nucleus ( $p + A$ ) and nucleus-nucleus ( $A + A$ ) collisions, yet these effects are poorly understood at low center-of-mass energies. In particular, the range $s \approx 10$ --20 GeV, where several CNM effects may compete at similar scales, has not been explored with high statistical precision. Mapping the QCD phase diagram similarly requires high-statistics $A + A$ data with broad rapidity and transverse-momentum coverage to probe the onset of deconfinement and the possible location of the QCD critical point (CP). Currently, such data are limited at 4.5 GeV $< s_{N N} < 7.7$ GeV A fixed-target program at the EIC would fill these gaps, providing CNM baselines and complementary data for QCD CP studies. By delivering high luminosity and systematic measurements across a broad range of nuclear targets, the program would link $p + A$ and $A + A$ systems at the same center-of-mass energies, enabling a unified, quantitative description of cold QCD matter and clarifying the interpretation of QGP signatures in $A + A$ collisions at low energies where comparable $p + A$ data are lacking. Finally, the program would offer a unique opportunity to measure nuclear cross sections critical for improving cosmic-ray models, including studies of space-radiation protection for both autonomous spacecraft and long-duration human spaceflight.
Comments:
11 pages, 7 figures
Subjects:
Nuclear Experiment (nucl-ex); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2603.00265 [pdf]
1 citation
14
[Submitted on 1 Mar 2026] (cross-list from hep-ph)
Covariant diffusion tensor for jet momentum broadening out of equilibrium
Isabella Danhoni🇺🇸 · Nicki Mullins🇺🇸 · Jorge Noronha🇺🇸
Jets are produced in the earliest stages of heavy-ion collisions, where they can interact with a medium that is not yet close to local equilibrium. Motivated by this, we generalize the usual jet transport coefficient $q^$ to a Lorentz-covariant diffusion tensor $q^^{μν}$ within a leading-order elastic (Boltzmann/Fokker--Planck) description of jet--medium interactions. The tensor formulation organizes medium effects in a frame-covariant way and reveals additional information beyond the standard scalar definition, including energy diffusion and off-diagonal components that encode correlations between energy and momentum exchange which are absent (or redundant) in equilibrium. We illustrate the formalism in (tree-level) massless $λ φ^{4}$ theory for isotropic but out-of-equilibrium states. For sufficiently large jet momentum, quantum statistical effects become subleading, so that the non-equilibrium evolution can be studied reliably in the classical (Boltzmann) limit. This allows us to solve the corresponding Boltzmann equation for the medium and determine the time dependence of $q^^{μν}$ as the system approaches equilibrium. We find that out-of-equilibrium corrections can either enhance or reduce jet momentum broadening, depending on the initial distribution function.
Comments:
Updated Refs
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2603.00844 [pdf]
3 citations
15
[Submitted on 1 Mar 2026] (cross-list from hep-lat)
Continuum limit of a qubit-regularized SU(3) lattice gauge theory with glueballs
Rui Xian Siew🇺🇸 · Shailesh Chandrasekharan🇺🇸 · Tanmoy Bhattacharya🇺🇸
We show that a simple qubit-regularized $SU (3)$ lattice gauge theory (LGT) on a plaquette chain admits a continuum limit with massive glueball excitations, providing a minimal toy model of strong interactions without quarks. By mapping the plaquette-chain Hamiltonian to the three-state quantum clock model in a magnetic field, we demonstrate that the theory can be tuned to a continuum limit governed at short distances by the $Z_{3}$ parafermion conformal field theory (CFT), which serves as the ultraviolet (UV) fixed point. A small relevant magnetic perturbation then drives the system to a massive continuum quantum field theory in the infrared (IR). The resulting relativistic massive particles can be interpreted as quasi one-dimensional analogues of glueballs. In the continuum theory we compute the ratio of the lowest glueball masses with opposite charge conjugation to be $m^{-} / m^{+} = 1.459 (2)$ and find $σ / m^{+} = 0.2648 (2)$ , where $σ$ is the string tension between a static quark and antiquark.
Comments:
5 pages main text, 5 figures; 23 pages Supplementary Material
Subjects:
High Energy Physics — Lattice (hep-lat); Strongly Correlated Electrons (cond-mat.str-el); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th); Quantum Physics (quant-ph)
arXiv:
2603.01215 [pdf]
4 citations
16
[Submitted on 2 Mar 2026] (cross-list from physics.atom-ph)
Probing a Fifth Force in Muonic Atoms through Lamb Shifts and Hyperfine Structure
Xiaoxuan Lin · Qian Wu · Wei Kou · Xurong Chen
Motivated by the ATOMKI anomalies in 8Be and 4He transitions, we study X17-induced Lamb shifts and hyperfine splittings in muonic atoms with stable nuclei up to Z <= 15. The bound-state problem is solved within the Gaussian Expansion Method using a unified Hamiltonian that includes the standard electromagnetic baseline together with vector and pseudoscalar X17 exchange. The spin-independent Lamb shift is described by a coherent vector muon-nucleus interaction, while the spin-dependent hyperfine sector is built isotope by isotope from shell-model spin fractions. We find a clear complementarity between mediator hypotheses: the vector Lamb-shift signal grows toward heavier nuclei, the vector hyperfine scenario favors odd-N nuclei, and the pseudoscalar scenario favors odd-Z nuclei. Using a signal-to-precision ratio, we identify muonic deuterium, muonic helium-3 ion, and muonic helium-4 ion as the most promising near-term Lamb-shift probes among systems with existing precision benchmarks. For future spectroscopy, the largest vector Lamb-shift signal is predicted in muonic silicon-29, while the leading 1S hyperfine targets are silicon-29 for the vector scenario and phosphorus-31 for the pseudoscalar scenario. The main theoretical uncertainty comes from the Schmidt-model treatment of nuclear spin content.
Comments:
22 pages, 6 figures, 13 tables
Subjects:
Atomic Physics (physics.atom-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2603.01429 [pdf]
2 citations
17
[Submitted on 2 Mar 2026] (cross-list from hep-ph)
Threshold Cusp Structures in the Presence of Isospin Symmetry Breaking
Katsuyoshi Sone🇯🇵 · Tetsuo Hyodo🇯🇵
We study the behavior of the cusp structures focusing on the isospin-breaking effects. The properties of the near-threshold exotic hadrons are encoded in the shapes of the cusp structures. In hadron scattering, it is often the case that the thresholds of isospin partner channels are located within a narrow energy region. To analyze the scattering in such systems, it is therefore essential to study the cusp structures that emerge at two closely separated thresholds with isospin symmetry breaking. In this study, we propose a practical representation of the scattering amplitude and show that the two neighboring cusp structures are related through the isospin symmetry.
Comments:
6 pages, 2 figures, Proceedings of 15th International Conference on Hypernuclear and Strange Particle Physics (HYP2025), 29th September-3rd October, 2025
Subjects:
High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2603.01518 [pdf]
1 citation
18
[Submitted on 2 Mar 2026] (cross-list from hep-lat)
Spatially inhomogeneous confinement-deconfinement phase transition in accelerated gluodynamics
Victor V. Braguta🇷🇺 · Vladimir A. Goy🇷🇺 · Jayanta Dey🇷🇺 · Artem A. Roenko🇷🇺
This study explores confinement-deconfinement transition properties of SU( $3$ ) Yang--Mills theory under weak accelerations at finite temperatures, using first-principles lattice simulations. The system is formulated in the Rindler spacetime, and the properties are studied from the perspective of a co-accelerating observer situated at the center of the lattice. We found that spatially separated confinement and deconfinement phases can coexist in the Rindler spacetime within certain intervals of temperature and acceleration. The position of the boundary between the phases is calculated as a function of temperature for several accelerations, and it is in accordance with the TE prediction, although a small deviation is observed. Moreover, in the weak acceleration regime, the critical temperature of the system is found to coincide with that of non-accelerated gluodynamics.
Comments:
10 pages, 4 figures, Proceedings of the 42nd International Symposium on Lattice Field Theory (Lattice 2025), 2-8 November 2025, Tata Institute of Fundamental Research, Mumbai, India
Subjects:
High Energy Physics — Lattice (hep-lat); General Relativity and Quantum Cosmology (gr-qc); High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
2603.01754 [pdf]
PoS(2026)·1 citation
19
[Submitted on 2 Mar 2026] (cross-list from hep-ph)
Effective degrees of freedom, trace anomaly and c-theorem like condition in the hadron resonance gas model
Hiroaki Kouno🇯🇵 · Riki Oshima🇯🇵 · Kouji Kashiwa🇯🇵
The relation between the effective degrees of freedom (EDOF) and the trace anomaly is studied in the hadron resonance gas (HRG) model. If we regard the thermodynamical relation as the evolution equation and define the EDOF as P/T^4, where P and T are the pressure and the temperature, respectively, we obtain the equation which relates to the trace anomaly. The structure of the equation resembles that of the so-called c-theorem, which asserts that the EDOF should not increase as the energy scale parameter decreases, in the two dimensional conformal field theory. There is a stationary point where the trace anomaly (modified trace anomaly) vanishes, and the scale symmetry is restored. To investigate the limiting temperature of the HRG model with the excluded volume effects, we consider two types of the c-theorem like conditions for the EDOF. The first condition requires that the EDOF should not decrease when T increases. This condition is equivalent to the condition that the trace anomaly (modified trace anomaly) should not be negative. The second condition requires that the EDOF should be convex downwards as a function of T. It is found that the first condition gives the limiting temperature of the HRG model with the excluded volume effect which is much higher than the crossover transition temperature obtained by the lattice QCD calculation and, at zero baryon number density, is close to the transition temperature in the pure gluonic theory, while the second one gives the limiting temperature which almost coincides with the one obtained by using the normalized baryon number fluctuation in the previous study and is consistent with the critical point predicted by the lattice QCD calculation.
Comments:
11pages, 17 figures. (v2) 12 pages, 18 figure. Fig. 18 has been newly added. Some sentences have been added. Some sentences have been improved
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:
2603.02085 [pdf]
0 citations

Affiliations

first authorsco-authorsvia INSPIRE