Nuclear Theory·nucl-th

Tuesday·October 21, 2025

14 papers—9 primary·5 cross-listed

10
Simulating Binary Neutron Star Mergers with Finite-temperature Equations of State: The influences of the slope of the symmetry energy and artificial heating
Henrique Gieg🇩🇪 · Maximiliano Ujevic🇧🇷 · Armen Sedrakian🇵🇱 · Tim Dietrich🇩🇪
We present a new set of numerical-relativity simulations of merging binary neutron stars, aiming to identify possible observable signatures of the slope of the symmetry energy $L_{sym}$ . To achieve this goal, we employ a set of equations of state based on a parameterization of the covariant density functional theory of nuclear matter that allows controlled variations of $L_{sym}$ and the skewness $Q_{sat}$ , holding the latter fixed. For a set of our simulations, we identify a steep energy gradient in the equation of state at subsaturation densities, which acts as a source of heating with subsequent stiffening produced by thermal support. Accounting for related structural modifications in the tidal deformability reconciles our results with theoretical expectations. On the other hand, we show that gravitational waves are unlikely to distinguish the role of $L_{sym}$ . In contrast to this, we find that the ejecta composition is significantly altered in our simulations, which employ an M1 moment scheme, when $L_{sym}$ is varied. Based on our extracted dynamical ejecta properties, we compute r-process yields and find that they are distinct for the different $L_{sym}$ , especially at lower mass numbers $A ≲ 120$ . This suggests that electromagnetic counterparts are more likely to exhibit signatures; however, a direct connection to $L_{sym}$ remains a challenge, given the complex interplay between details of the ejecta properties and the kilonova signal.
↳ gr-qcastro-ph.HEastro-ph.SRnucl-thPRD(2025)·6 citations
11
CE $ν$ NS Search with Cryogenic Sapphire Detectors at MINER: Results from the TRIGA reactor data and Future Sensitivity at HFIR
D. Mondal🇮🇳 · W. Baker🇺🇸 · M. Chaudhuri🇮🇳 · J. B. Dent🇺🇸 · R. Dey🇮🇳 · B. Dutta🇺🇸 · V. Iyer🇨🇦 · A. Jastram🇺🇸 · V. K. S. Kashyap🇮🇳 · A. Kubik🇨🇦 · K. Lang🇺🇸 · R. Mahapatra🇺🇸 and 11 other authors
We report on a search for coherent elastic neutrino--nucleus scattering (CE $ν$ NS) using cryogenic sapphire (Al $_{2}$ O $_{3}$ ) detectors deployed at the Mitchell Institute Neutrino Experiment at Reactor (MINER), located near the 1~MW $_{th}$ TRIGA research reactor at Texas A\&M University. The experiment operated with a primary detector mass of 72~g and achieved a baseline energy resolution of $\sim 40$ ~eV. Using exposures of 158~g-days (reactor-on) and 381~g-days (reactor-off), we performed a statistical background subtraction in the energy region of 0.25--3~keV. A GEANT4 simulation has been performed to understand the reactor-correlated background present in the data and it agrees with our observations. The resulting best-fit ratio of the observed CE $ν$ NS rate to the Standard Model prediction after rejecting the reactor induced background from the data with the help of simulation, is $ρ = 0.26 \pm 1534.74 (stat) \pm 0.05 (sys)$ with a significance of $0.007 \pm 0.022 (stat) \pm 0.001 (sys)$ . This low significance indicates a high background rate at low energies. To have enhanced sensitivity, the MINER collaboration plans to relocate the experiment to the 85~MW $_{th}$ High Flux Isotope Reactor (HFIR) at Oak Ridge National Laboratory (ORNL). With improved shielding, increased detector mass, and higher antineutrino flux, the upgraded setup is projected to achieve a 3 $σ$ CE $ν$ NS detection within 30~kg $\cdot$ days of exposure.
↳ nucl-exhep-exnucl-thphysics.ins-detPRD(2026)·6 citations
12
Rapidly rotating hot nuclear and hypernuclear compact stars: integral parameters and universal relations
Stefanos Tsiopelas🇵🇱 · Armen Sedrakian🇵🇱 · Micaela Oertel🇫🇷
In this work, we investigate hot, isentropic compact stars in the limiting cases of static and maximally rotating configurations, focusing on how variations in the symmetry energy of the equation of state derived from covariant density functional theory affect stellar properties. We consider both nucleonic and hyperonic matter with systematically varied symmetry energy slopes, fixed entropies per baryon $s / k_{B} = 1$ and 3, and electron fractions $Y_{e} = 0.1$ and $Y_{e} = 0.4$ , representative of conditions in binary neutron star mergers and proto-neutron stars. We compute and analyze mass--radius and moment--of--inertia--mass relations, as well as the dependence of the Keplerian (mass-shedding) frequency on mass, angular momentum, and the ratio of kinetic to gravitational energy. Furthermore, we show that several universal relations between global properties remain valid across both nucleonic and hyperonic equations of state with varying symmetry energy, both in the static and Keplerian limit, and for various combinations of the fixed entropy and electron fraction.
↳ astro-ph.HEastro-ph.SRgr-qcnucl-thPRD(2026)·3 citations
13
Flux-Conservative BDNK Hydrodynamics and Shock Regularization
Nicolas Clarisse🇺🇸 · Eduardo O. Pinho🇧🇷 · Teerthal Patel🇺🇸 · Fabio S. Bemfica🇺🇸 · Mauricio Hippert🇧🇷 · Jorge Noronha🇺🇸
We present a new, first-order, flux-conservative formulation of relativistic viscous hydrodynamics in the BDNK framework, applicable to conformal and nonconformal fluids at zero chemical potential. Focusing on the conformal case in 1+1 dimensions, we numerically solve the equations of motion for two classes of consistent initial data and assess the robustness of the resulting solutions with respect to changing the hydrodynamic frame. Our flux-conservative formulation does not exhibit spurious oscillatory structures within the regime of validity of BDNK theory (the hydrodynamic-frame-robust regime), corresponding to sufficiently small Knudsen numbers. Using this flux-conservative approach, we numerically investigate the potential formation of shocks and their fate in BDNK in 1+1D using smooth initial data known to produce shocks in the relativistic Euler equations. For the type of initial data we consider, we show that the sharp features formed in Euler are prevented by the hyperbolic viscous BDNK equations. The prevention of shock formation we observe occurs in the frame-robust regime of BDNK. This, however, does not preclude the formation of shocks in BDNK for different smooth initial data. The reliability of our results is supported by systematic numerical convergence testing, which is used to assess shock indicators, simulation performance, and the robustness of solutions for different hydrodynamic frames.
↳ gr-qchep-thnucl-thPRD(2026)·8 citations
14
Heavy flavor transport in the QGP medium
Bruno Scheihing-Hitschfeld
I review recent developments on heavy flavor transport in the QGP medium, along two directions. The first is the transport of individual open heavy quarks. Leveraging the tools of heavy quark effective theory, recent work revealed a novel connection between the evolution equation of the heavy quark phase space distribution, the conditions for kinetic equilibration to take place, and a non-perturbatively defined expectation value of a Wilson loop characterized by the heavy quark velocity. Using these developments, I discuss results from a first exploration of the ensuing stopping and equilibration dynamics of heavy quarks in a strongly coupled environment. The second direction is the transport of quarkonia, bound states of heavy quarks, where novel Generalized Gluon Distributions have been recently defined and calculated in the framework of potential non-relativistic QCD. I discuss their application to the dynamics of quarkonium in heavy-ion collisions, highlighting the need to account for non-Markovian effects in the interactions between the heavy quark pair and quark-gluon plasma -- which have thus far resisted a systematic characterization.
↳ hep-phnucl-thPoS(2026)·0 citations

Affiliations

first authorsco-authorsvia INSPIRE

Simulating Binary Neutron Star Mergers with Finite-temperature Equations of State: The influences of the slope of the symmetry energy and artificial heating

CEνNS Search with Cryogenic Sapphire Detectors at MINER: Results from the TRIGA reactor data and Future Sensitivity at HFIR

Rapidly rotating hot nuclear and hypernuclear compact stars: integral parameters and universal relations

Flux-Conservative BDNK Hydrodynamics and Shock Regularization

Heavy flavor transport in the QGP medium

Affiliations

CE $ν$ NS Search with Cryogenic Sapphire Detectors at MINER: Results from the TRIGA reactor data and Future Sensitivity at HFIR