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Nuclear Theory·nucl-th

Monday·August 24, 2026

11 papers—6 primary·5 cross-listed

All11Primary6Cross-lists5
  1. 01

    Trace Anomaly and Effective Topological Sources in Neutron Stars

    Federico Nola🇮🇹

    This work investigates whether the trace anomaly can diagnose the stellar response to a topological scalar field in tensor multi-scalar gravity. Eleven cold tabulated equations of state (EoSs) were examined, with six retained after general relativistic (GR) thermodynamic and causality checks. Their fiducial topological configurations were compared with the corresponding GR models under complementary matching prescriptions. After controlling for stellar mass and EoS dependence, the GR trace source strength remained strongly correlated with the topological mass response, with a partial Spearman coefficient . Near , the topological configurations were systematically more compact, with Jordan frame radius reductions of -- at fixed baryonic mass and -- at fixed gravitational mass. These shifts are comparable to current uncertainties from the Neutron Star Interior Composition Explorer (NICER) and produce source dependent observational effects. Despite the global deformation, the interior effective source remained matter dominated, with a median topological contribution of about . The GR matter trace therefore emerges as a useful diagnostic of the fiducial topological stellar response.

    nucl-thastro-ph.HEgr-qc0 citations
  2. 02

    Thermodynamically Consistent Merging of Multidimensional QCD Equations of State

    Prachi Garella🇺🇸 · Yumu Yang🇺🇸 · Musa R. Khan🇺🇸 · Tulio E. Restrepo🇺🇸 · Joaquin Grefa🇺🇸 · Johannes Jahan🇺🇸 · Mauricio Hippert🇧🇷 · Jorge Noronha🇺🇸 · Claudia Ratti🇺🇸 · Romulo Rougemont🇧🇷

    We present a thermodynamically consistent framework for merging complementary models into a multidimensional QCD equation of state. An internal mixing variable is determined by minimizing a single grand potential at fixed temperature and baryon chemical potential, ensuring thermodynamic consistency and stability. Interactions between the components allow for a crossover, a critical endpoint, and a first-order transition. As a proof of principle, we merge a quantum van der Waals hadron-resonance-gas model with a holographic Einstein--Maxwell--Dilaton model. The resulting equation of state reproduces the appropriate description in each regime, agrees well with available lattice-QCD results, and is suitable for heavy-ion phenomenology over a broad range of temperature and baryon chemical potential.

    nucl-th0 citations
  3. 03

    Evaluation of Phenomenological Characteristics of the Two-Proton Decay of the 45Fe Nucleus

    D. E. Lyubashevsky · S. G. Kadmensky · J. D. Shcherbina

    A Green-function formalism describing sequential and virtual two-proton (2p) radi-oactivity is developed on the basis of the multiparticle theory of one-proton decay. In the proposed approach, two-proton emission is treated as two consecutive one-proton transitions connected by the Green's function of the intermediate nucleus, al-lowing both on-shell and off-shell intermediate states to be consistently included. Analytical expressions are derived for the total and partial 2p-decay widths as well as for the angular distribution of the emitted protons. The formalism is applied to the ground-state two-proton decay of 45Fe leading to the ground state of 43Cr within the superfluid nuclear model. Calculations demonstrate a pronounced dependence of the decay characteristics on the choice of the single-particle nuclear potential. It is shown that an appropriate choice of the shell potential allows the experimental decay width and the measured proton angular distribution to be reproduced simultaneously. These results indicate that the proposed Green-function approach provides a consistent description of virtual sequential two-proton decay and offers an alternative framework for the interpretation of true two-proton radioactivity.

    nucl-th0 citations
  4. 04

    Fresh Look at Polarized Deuterons at the Nuclotron/NICA \& HIAF and Beyond

    B. Gou · V.P. Ladygin · N.N. Nikolaev · F. Rathmann · A.J. Silenko · Y.N.Uzikov

    Being a spin-1 particle, the deuteron, when polarized, offers access to a wide range of interesting tensor observables. A quest for tensor asymmetries is at the heart of the spin physics with polarized deuterons at future colliders, and calls for frequent tensor polarization flips in storage rings or in deuterium targets. Here we focus on the JEDI developed technique of the Fourier analysis of the horizontal polarization oscillations under continuous radiofrequency driven spin flips. The so generated time-stamped oscillating helicity of stored particles paves the way to the nucleon/nucleus spin structure studies and to the search for the parity violation. Simultaneously a whole set of tensor spin asymmetries, including the off-diagonal ones needed for searches for the T-violation beyond the Standard Model, will be produced. A crucial ingredient is a long polarization lifetime, and we report the first analytic treatment of decoherence of the tensor polarization under continuous radiofrequency spin flips. Our principal conclusion is that at low- and intermediate-energy accelerators the deuteron polarization lifetime could be in the ballpark of several hours, making the oscillating polarization approach viable at Nuclotron/NICA and HIAF. We comment on a utility of the flattop spin-tensor dichroism via oscillations in the cross section of interaction of deuterons in the internal target as a monitor of the tensor polarization. Simultaneously, the dichroism effect can be used for measuring the spin precession frequences and as a comagnetometer to synchronize spin phases of colliding bunches in a collider.

    nucl-thNatural Sci.Rev.(2026)·0 citations
  5. 05

    Neutron star matter with hyperons: Bayesian comparison of nucleonic and SU(6)/SU(3) hyperonic models

    Athira S. · Vishal Parmar🇮🇳 · Monika Sinha🇮🇳 · Ignazio Bombaci🇮🇹

    We investigate neutron star matter with hyperons within a density-dependent relativistic mean-field framework using Bayesian inference, considering three composition scenarios: purely nucleonic matter, hyperonic matter under SU(6) flavor symmetry, and hyperonic matter under SU(3) symmetry with free vector-sector parameters. The analysis incorporates constraints from empirical nuclear matter properties, theoretical inputs at low densities, and multimessenger observations of neutron stars. We find that the SU(6) scheme, grounded in the quark model and isospin counting rule, leads to a significantly softer equation of state. In contrast, the additional flexibility of the SU(3) framework enhances vector repulsion and yields a comparatively stiffer equation of state consistent with observational bounds across the explored parameter space; in particular, the posterior distributions favor values of the vector coupling ratio lower than the SU(6) limit . These differences are reflected in neutron star observables, including mass--radius relations, tidal deformabilities, direct Urca thresholds, and oscillation properties, all of which remain compatible with current constraints within the SU(3) scenario. We further examine structural signatures through the curvature of the mass--radius relation and find that, although hyperon-rich configurations can induce noticeable variations, such features depend sensitively on the stiffness of the equation of state and are therefore not universally robust indicators. Bayesian model comparison further shows that present constraints do not meaningfully discriminate between the purely nucleonic and SU(3) hyperonic scenarios, while providing positive, but not decisive, evidence against the more restrictive SU(6) framework.

    nucl-thastro-ph.HEastro-ph.SR0 citations
  6. 06

    Bottomonium transport in the sQGP at RHIC and the LHC

    Biaogang Wu🇺🇸 · Jacob Boyd🇺🇸 · Ralf Rapp🇺🇸

    Bottomonium transport is studied in heavy-ion collisions at RHIC and the LHC by implementing a kinetic rate equation into (3+1)D viscous hydrodynamic simulations of an expanding quark-gluon plasma (QGP). The two main transport parameters are the inelastic reaction rates and equilibrium limits for each individual bottomonium state, . The former are taken from the thermodynamic -matrix formalism with recent constraints from lattice-QCD and including interference effects and in-medium binding energies, resulting in large rates characteristic of a strongly coupled QGP. The equilibrium limits are evaluated from pertinent in-medium bottomonium and bottom-quark masses. The calculation of observables includes a total of nine states (up to 3 and 2) with a feed-down matrix estimated from vacuum branching fractions. At the LHC, the large reaction rates rapidly suppress the initial population of excited states, rendering regeneration their main source even in rather peripheral collisions, while for the more strongly bound ground state , a significant primordial component survives in central collisions. On the other hand, at RHIC energies, regeneration is overall a smaller effect. Together with effects from nuclear absorption, this offers an explanation for the experimental observation that production at RHIC and the LHC is of comparable magnitude despite the significantly higher temperatures reached in the QGP at the LHC.

    nucl-th0 citations

Affiliations

first authorsco-authorsvia INSPIRE