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Nuclear Theory·nucl-th

Friday·May 22, 2026

6 papers—4 primary·2 cross-listed

All6Primary4Cross-lists2
  1. 05

    Equation of State at High Baryon Densities from a Thermodynamically Informed Neural Network

    Musfer Adzhymambetov🇺🇦

    We present a four-dimensional equation of state for strongly interacting matter at finite temperature and conserved charge densities, constructed using a deep neural network. It is designed for direct use in hybrid models of relativistic heavy-ion collisions: it reproduces hadron resonance gas thermodynamics at typical particlization scales, is consistent with lattice QCD at low baryon chemical potential, and extrapolates into the high-density region inaccessible to either approach, which is precisely the regime targeted by RHIC BES, FAIR, HADES, and CBM. Thermodynamic consistency throughout the full phase space is enforced via a physics-informed loss function. We demonstrate the developed equation of state by implementing it at zero net strangeness and fixed electric-to-baryon charge ratio within the integrated hydrokinetic model.

    ↳ hep-phnucl-th0 citations
  2. 06

    Shielded inner-shell transitions in atomic samarium for tests of fundamental physics

    R. Aramyan🇩🇪 · D. Budker🇩🇪 · V. A. Dzuba🇦🇺 · V. V. Flambaum🇦🇺 · S. G. Porsev🇺🇸 · M. S. Safronova🇺🇸 · O. Tretiak🇩🇪 · K. Zhang🇩🇪

    Forbidden atomic transitions provide some of the most stringent low-energy tests of physics beyond the Standard Model, with sensitivity set by the interplay between the sought-for signals and systematics suppressed by symmetry. Here we identify the previously unobserved D level of neutral samarium at , opening the FD inner-shell transition for precision spectroscopy. Candidate lines extracted from dual-comb absorption spectra were assigned using double-resonance population-depletion and sequential-excitation measurements. The observed pressure broadening, , and pressure shift, , indicate an inner-shell -transition shielded from external perturbations. Many-body calculations predict a metastable lifetime (quality factor ), large sensitivity coefficients for variation of the fine-structure constant, and a nuclear-spin-dependent parity-violation amplitude comparable to that of cesium. Crucially, the selection rule suppresses by symmetry both the nuclear-spin-independent parity-violation channel and the M1 and E2 backgrounds that complicated previous heavy-atom experiments, yielding a uniquely clean window onto the nuclear anapole moment. The two stable spin- isotopes of samarium provide a remarkable opportunity to largely cancel atomic-structure uncertainties by measuring the ratio of parity-violation effects in the two isotopes. These results establish neutral samarium as a platform for inner-shell precision spectroscopy and tests of physics beyond the Standard Model.

    ↳ physics.atom-phnucl-thphysics.opticsquant-ph0 citations

Affiliations

first authorsco-authorsvia INSPIRE