Nuclear Theory·nucl-th

Monday·March 9, 2026

8 papers—3 primary·5 cross-listed

01
[Submitted on 4 Mar 2026]
Cost-efficient Bayesian emulation of quark-gluon plasma modeling with variable statistical precision
R. Ehlers🇺🇸 · Y. Ji🇺🇸 · P. M. Jacobs🇺🇸 · S. Mak🇺🇸
We present VarP-GP, a new cost-efficient Bayesian emulator for expensive computational models with variable statistical precision. We focus on the interpretation of measurements of the quark-gluon plasma (QGP) generated in high-energy nuclear collisions, through comparison to numerical models using Bayesian Inference. Such inference calculations are computationally expensive and require surrogate model emulation, which is commonly implemented using Machine Learning (ML) based Gaussian processes (GPs). Emulator training data are generated by Monte Carlo simulations whose numerical precision depends on the computational resources utilized; improved precision entails greater computational cost. This study utilizes JETSCAPE simulations of inclusive hadron and jet measurements in nuclear collisions at RHIC and the LHC. The VarP-GP emulator combines information from multiple simulation runs with varying precision across the model parameter space, taking advantage of the smoothness in that space of QCD-driven processes. Comparison to a traditional emulator approach shows a marked reduction in emulator uncertainty at fixed computational cost, indicating that knowledge of the overall contours of the parameter design space is more important for precise emulation than detailed information at a more limited number of design points. As an initial application of VarP-GP, a computationally-expensive model parameter sensitivity study of jet quenching data is reported. The VarP-GP emulator enables new multi-model and many-observable calibrations of QGP data and modeling, which would otherwise not be possible with achievable computing resources.
Comments:
Published version
Subjects:
Nuclear Theory (nucl-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex)
arXiv:
2603.05545 [pdf]
0 citations
02
[Submitted on 6 Mar 2026]
Impact of microscopic structural transitions on particle stability and lifetimes of hot nuclei
Mamta Aggarwal · Pranali Parab · G. Saxena
The impact of temperature-induced deformations and shape fluctuations on the particle stability and decay processes has been investigated across the isotopes of hot nuclear systems with $Z = 28$ to $50$ , with focus on astrophysically crucial pathways at excitation energies relevant to stellar environments. We perform global finite-temperature analysis using the statistical theory of hot nuclei combined with the triaxially deformed Nilsson Hamiltonian and Strutinsky's prescription, and explore the interplay between deformation, shell quenching, separation energies, and $β$ -decay characteristics at finite temperatures. Our results show that around critical temperatures $T_{c} \approx 1$ -- $2$ MeV, where the shell quenching effects become predominant, the nuclear deformation reduces and the shape undergoes a transition to the spherical configuration. Our computed neutron and proton separation energies, which usually decrease with increasing temperature, implying the reduced binding in hot nuclei, occasionally show an enhancement in some nuclei at reduced deformation around $T_{c}$ that shifts the last unbound nucleon to the bound, stabilizing the nucleus by shifting the drip-line boundaries. A few nuclei are found to show one- and two-neutron drip line expansion with temperature. Moreover, the temperature-induced changes in deformation strongly correlate with the marked variations in our calculated $Q_{β}$ values and lifetimes, underscoring their impact on weak interaction rates. These findings provide insight into the sensitivity of particle stability and weak-interaction observables to thermal effects and may serve as complementary inputs for modeling nuclear processes in hot astrophysical environments.
Comments:
8 pages, 8 figures
Subjects:
Nuclear Theory (nucl-th)
arXiv:
2603.06035 [pdf]
PLB(2026)·1 citation
03
[Submitted on 6 Mar 2026]
Inverse-mapped density-dependent relativistic mean-field inference of the neutron-star equation of state with multi-messenger constraints
Wen-Jie Xie · Cheng-Jun Xia
We perform a Bayesian inference of the equation of state (EOS) of cold dense matter within a density-dependent relativistic mean-field (DD-RMF) model. An explicit inverse-mapping procedure reconstructs the density-dependent couplings from a physically interpretable ten-dimensional parameter set while enforcing thermodynamic consistency together with stability and causality conditions. The EOS is constrained by complementary multi-messenger data including chiral effective field theory calculations at low density, heavy-ion collision flow information at intermediate densities, NICER mass-radius posteriors, and the existence of approximately two-solar-mass pulsars. The combined constraints strongly restrict both isoscalar and isovector sectors. In particular, the chiral effective field theory band favors a relatively soft symmetry-energy slope around 38 MeV, corresponding to a compact canonical neutron-star radius of about 11.6 km. To reconcile the intermediate-density softness suggested by heavy-ion data with the high-density stiffness required by massive pulsars, the posterior prefers a moderately large Dirac effective mass at saturation together with correlated high-density limits of the scalar and vector couplings. The resulting sound-speed profile remains causal and shows significant stiffening above the conformal limit at several times nuclear saturation density, indicating strongly interacting matter in neutron-star cores. Evidence diagnostics indicate strong compatibility among the adopted constraints within the present DD-RMF framework.
Comments:
17 pages, 11 fiugres
Subjects:
Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE)
arXiv:
2603.06128 [pdf]
3 citations
04
[Submitted on 6 Mar 2026] (cross-list from nucl-ex)
Study of Collective Phenomena in Heavy-Ion Collisions Using CMS Open Data
Allan E. F. G. Ferreira🇧🇷 · Cesar A. Bernardes🇧🇷
In this work, we present preliminary results from a measurement of the recently proposed observable, $v_{0} (p_{T})$ , in lead-lead (PbPb) collisions at $s_{N N} = 2.76 TeV$ , using public data from the CMS Open Data portal. This observable is directly sensitive to radial flow and characterizes the transverse momentum ( $p_{T}$ ) dependence of radial flow fluctuations, serving as probe of collective phenomena in the quark-gluon plasma (QGP) formed in heavy-ion collisions. Consistently with the ATLAS results at $s_{N N} = 5.02 TeV$ , we observe the three key features of collective radial flow: long-range correlations in pseudorapidity ( $η$ ), a centrality-independent shape as a function of $p_{T}$ , and factorization in $p_{T}$ . The results presented in this work are generally compatible, within uncertainties, with the ATLAS measurements at $s_{N N} = 5.02 TeV$ reported in Phys. Rev. Lett. 136, 032301 (2026).
Comments:
8 pages, 5 figures, Proceedings of Workshop of Advances in QCD at the LHC and the EIC
Subjects:
Nuclear Experiment (nucl-ex); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
2603.05798 [pdf]
0 citations
05
[Submitted on 6 Mar 2026] (cross-list from hep-lat)
A Lattice QCD study of $p - Λ$ scattering in continuum and chiral limits
Hang Liu🇨🇳 · Liuming Liu🇨🇳 · Jin-Xin Tan🇨🇳 · Wei Wang🇨🇳 · Haobo Yan🇨🇳 · Qian-Teng Zhu🇨🇳
We present a first systematic study of $I = 1/2$ proton- $Λ$ ( $p$ - $Λ$ ) scattering from lattice QCD, using seven sets of $(2 + 1)$ -flavor lattice ensembles with pion masses spanning 135-317 MeV and three lattice spacings with $a = (0.052, 0.077, 0.105)$ fm. Using Lüscher's finite-volume method, effective range expansion and chiral/continuum extrapolations, we obtain the inverse of scattering length and effective range for the $^{1} S_{0}$ channel as 0.177(83) GeV and 2.9(1.4) fm, and for the $^{3} S_{1}$ channel as 0.016(76) GeV and 1.8(1.1) fm. From the derived S-wave phase shifts, we provide an estimate of the $p - Λ$ scattering cross section. Our results for scattering length, effective range and cross sections are in good agreement with available experimental measurements. We also find that the $p - Λ$ system sustains attractive interactions. These results provide critical input for the unification of nuclear force theories and the construction of neutron star equations of state.
Comments:
5 pages + supplemental material, 5 figures
Subjects:
High Energy Physics — Lattice (hep-lat); High Energy Physics — Experiment (hep-ex); High Energy Physics — Phenomenology (hep-ph); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
2603.05854 [pdf]
2 citations
06
[Submitted on 6 Mar 2026] (cross-list from hep-ph)
Lattice QCD constraints on pion electroproduction off a nucleon
Yu Zhuge🇨🇳 · Zhan-Wei Liu🇨🇳 · Derek B. Leinweber🇦🇺 · Anthony W. Thomas🇦🇺
Very recently, a lattice QCD collaboration has explored threshold pion electroproduction near the physical pion mass and has simulated the relevant multipole amplitudes. Different multipole amplitudes are usually entangled in experimental data, and thus extracting each of them independently from first principles provides additional essential constraints on phenomenological theories. We use nonperturbative Hamiltonian theory to investigate the electroproduction process, providing an advanced approach with additional two-particle coupled channels to acquire the physical electric dipole amplitudes from the original lattice QCD data. We note that future lattice QCD simulations of the electric dipole amplitudes at higher energies will be much closer to their physical counterparts than the current ones near threshold. In addition, we obtain a new expression which, like that of Lellouch-Lüscher, depends only on the final-state interactions but provides both the real and imaginary parts of the transition amplitudes.
Comments:
5+2 pages, 2 figures, 2 tables
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Lattice (hep-lat); Nuclear Theory (nucl-th)
arXiv:
2603.06055 [pdf]
0 citations
07
[Submitted on 6 Mar 2026] (cross-list from astro-ph.HE)
Survival of ultraheavy nuclei in astrophysical sources: applications to protomagnetar outflows
Nick Ekanger · Mukul Bhattacharya · Kohta Murase · Shunsaku Horiuchi
Outflows of rapidly rotating protomagnetars have been considered as attractive sites for the synthesis of nuclei heavier than iron, but the question remains whether these nuclei are able to survive against photodisintegration as they make their way out of their formation environments. In this work, we present new analytic fitting formulae for the photodisintegration cross sections applicable to heavy nuclei beyond iron. We confirm that the results from the TALYS simulations are consistent with the theory of the giant dipole resonance, and apply the obtained new formulae to investigate whether ultraheavy nuclei entrained in protomagnetar outflows can be disintegrated by thermal and nonthermal photons before leaving the stellar envelope. We explore two outflow models: a spherical wind model and a jetted outflow model. For nuclei accelerated to the bulk speed of these outflows, their survival depends on the model and engine properties. For spherical winds, nuclei may survive for the first $\sim 100 s$ post-core collapse, but as the wind Lorentz factor increases, the photodisintegration optical depth sharply rises and nuclei may no longer survive. For the jetted outflows arising from progenitors surrounded with stellar envelopes, nuclei can only survive before the jet breakout time in cases where the central engine has low spin-down energy, that is, with a low magnetic field strength and longer spin period. In progenitors with more extended envelopes, the jet break out time is much longer, allowing for nonthermal photons to readily photodisintegrate nuclei in high spin-down energy cases. These results also have implications for the capabilities of protomagnetars to source ultra-high energy cosmic ray nuclei.
Comments:
13 pages, 5 figures, 1 table, will submit to PRD
Subjects:
High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2603.06381 [pdf]
2 citations
08
[Submitted on 6 Mar 2026] (cross-list from hep-th)
Chiral-Maxwell Cavity EFT: Photon Condensation and Quantum-Optics Limits
Fabrizio Canfora🇨🇱 · Mauricio Ipinza🇨🇱 · Simon Riquelme🇨🇱
We develop an analytic, fully field-theoretic description of how a hadronic medium can induce photon condensation in a cavity. Starting from leading-order Chiral Perturbation Theory minimally coupled to Maxwell theory, we construct a consistent truncation to the lowest hadronic and gauge modes that still supports a non-vanishing baryon (topological) density. The resulting reduced dynamics is an effective $1+1$ theory whose couplings retain memory of the three-dimensional cavity through discrete winding and transverse holonomy data. Integrating out the heavy hadronic mode at one loop yields a gauge-invariant effective potential for the lowest photonic cavity mode, from which we derive analytic criteria for a condensed window. In the opposite hierarchy, integrating out the gauge mode produces a one-loop deformation of a sine--Gordon-type EFT for the chiral mode and makes explicit where scale separation fails and the full coupled system must be kept. Upon quantization, the reduced theory maps onto standard nonlinear quantum-optics Hamiltonians, including a two-photon Rabi limit and quartic single-mode photonic models whose trivial and condensed branches obey distinct selection rules. This provides a concrete bridge between finite-density hadronic physics and experimentally familiar nonlinear-cavity diagnostics.
Comments:
48 pages, 6 figures
Subjects:
High Energy Physics — Theory (hep-th); High Energy Physics — Phenomenology (hep-ph); Nuclear Theory (nucl-th)
arXiv:
2603.06547 [pdf]
0 citations

Affiliations

first authorsco-authorsvia INSPIRE