PaperPanorama
FAQ

Nuclear Theory·nucl-th

Tuesday·September 16, 2025

14 papers—5 primary·9 cross-listed

All14Primary5Cross-lists9
  1. 01

    [Submitted on 12 Sept 2025]

    Theoretical Signatures of QCD Phase Transitions in Compact Astrophysical Systems

    Debarshi Mukherjee🇮🇳

    We investigate theoretical signatures of first-order QCD phase transitions in high-density astrophysical systems through a framework combining lattice QCD, effective field theories, and multimessenger constraints. Hybrid equations of state with Maxwell and Gibbs constructions, constrained by lattice QCD at finite temperature and baryon chemical potential up to mu_B/T < 3, interpolate consistently between chiral effective field theory at nuclear densities and perturbative QCD at asymptotic densities. Applying these models to static neutron stars via Tolman-Oppenheimer-Volkoff equations and to binary mergers via relativistic hydrodynamics, we find distinctive signatures: (i) twin star branches with 0.5-2.0 km radius differences at fixed mass, (ii) equation of state softening in coexistence regions reducing maximum masses by 0.2-0.4 solar masses, (iii) delayed post-merger gravitational-wave frequency shifts of 200-400 Hz, and (iv) enhanced neutrino emission during phase transitions. Confronted with multimessenger constraints from GW170817, NICER observations of PSR J0740+6620 and PSR J0030+0451, and perturbative QCD, our models suggest strong first-order transitions are marginally consistent with current data but produce signatures detectable by next-generation detectors. Neutron star core sound speeds satisfy c_s^2 < 0.5c^2, with transient conformal bound violations in 2-4 times saturation density. This framework yields quantitative predictions for the Einstein Telescope and Cosmic Explorer, establishing foundations for precision QCD matter tests and possible quark matter discovery.

    Comments:
    This manuscript is being withdrawn by the author because it does not meet the scientific standards the author wishes to maintain in the permanent literature. The results and presentation are considered preliminary and should not be cited
    Subjects:
    Nuclear Theory (nucl-th); High Energy Astrophysical Phenomena (astro-ph.HE); High Energy Physics — Lattice (hep-lat)
    arXiv:
    2509.10589 [pdf]
    0 citations
  2. 02

    [Submitted on 12 Sept 2025]

    SIV Guided Resolution of the Lithium-7 BBN Problem

    Vesselin G. Gueorguiev🇧🇬

    A possible resolution of the Li problem within the Standard Model Big-Bang Nucleosynthesis is presented. The key idea originates from the application of the Scale-Invariant Vacuum (SIV) paradigm to the BBN. However, here we arrive at the conclusion that Reparametrization Invariant Symmetry Scaling (RISS) is the more appropriate framework for the epoch of the BBN and use the SIV only as a guidance framework. The outcome is fit to the observed primordial abundances of He, D/H, He/D, and fit of when including Li/H observations. The results are obtained and compared to the known standard BBN values by utilizing the publicly available PRIMAT code. The resolution of the Li problem requires SIV-guided deviation from the local thermal equilibrium during BBN, such that the thermal energy of matter and radiation scale differently with respect to the SIV-conformal factor during the BBN epoch. This may be viewed as conformal symmetry breaking due to cooling of plasma and the properties of matter. As such, the framework may be of relevance to the problem of the nuclear fusion as well. The deduced baryon matter content is for unbroken SIV and for partially broken SIV, but with in both cases, which signals preference for Reparametrization Invariant Symmetry Scaling (RISS) over the conventional SIV viewpoint. Applying the RISS paradigm results in and with clear departure of away from the naive SIV suggested value. In all the cases where the Li problem is resolved, the baryon content is significantly higher than the usually accepted value of within the CDM. \keywords{Cosmology -- Primordial Nucleosynthesis -- dark matter, Reparametrization Invariance, Scale-Invariant Vacuum (SIV)}

    Comments:
    4 pages, two column text, 1 figure and 1 table, to appear in A&A as letter article
    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2509.10721 [pdf]
    Astron.Astrophys.(2025)·0 citations
  3. 03

    [Submitted on 14 Sept 2025]

    Data-driven trap theory for nuclear scattering

    Hantao Zhang · Dong Bai · Xilin Zhang · Zhongzhou Ren

    We present a novel data-driven trap theory (abbreviated as DDTT) for nuclear scattering, which aims to overcome the limitations of the traditional trap method in dealing with narrow potential wells, while also providing a more efficient framework for handling long-range Coulomb interactions. As proof-of-concept examples, we employ this unified theory to analyze the elastic scattering of nucleon-nucleon and nucleon-{\alpha} systems. DDTT can successfully produce results consistent with those from traditional approaches, highlighting its significance for ab initio light nuclei scattering studies and potential for applications in the heavier mass region.

    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2509.11072 [pdf]
    0 citations
  4. 04

    [Submitted on 14 Sept 2025]

    Few-Nucleon Systems within Finite-Cutoff Pionless EFT

    Liron H. Avraham🇮🇱 · Betzalel Bazak🇮🇱

    We investigate pionless effective field theory (\nopieft) with finite-cutoff regularization as a framework for describing few-nucleon systems. This formulation incorporates effective-range effects already at leading order (LO), thereby reaching next-to-leading-order (NLO) accuracy while maintaining computational efficiency. Using correlated-Gaussian stochastic variational methods in a weak harmonic-oscillator trap, together with neutral and Coulomb-modified quantization conditions, we calculate binding energies and low-energy -wave scattering parameters for systems with up to five nucleons. At an optimal cutoff, the computed binding energies of the deuteron, triton, helion, and alpha particle reproduce experimental values at the percent level once a three-body force is included. Scattering parameters for proton--proton, nucleon--deuteron, nucleon--triton, proton--helion, deuteron--deuteron, and nucleon--alpha channels are obtained and found to be consistent with both experimental data and existing NLO \nopieft\ calculations. These results demonstrate that finite-cutoff \nopieft\ offers a robust and predictive framework for few-body nuclear physics.

    Subjects:
    Nuclear Theory (nucl-th)
    arXiv:
    2509.11180 [pdf]
    PLB(2026)·5 citations
  5. 05

    [Submitted on 15 Sept 2025]

    Nuclear transitions on demand

    C.-J. Yang

    I show a way to tune photo-nuclear cross section effectively and therefore achieve nuclear transitions "on demand". The method is based on combinatorial enhancement of multiphoton processes under intense conditions. Taking advantage of recent advances in high-power laser systems (HPLS) and nuclear structure calculations, efficient control of nuclear transitions up to E4 in multipolarity can be reached today. The same idea can be extended to the search for rare transitions and hidden states, which applies to the -beams generated from conventional sources as well.

    Comments:
    7 pages, 5 figures, to appear in the Proceedings of the 14th Int. Spring Seminar on Nuclear Physics: "Cutting-edge developments in nuclear structure physics", one new figure added
    Subjects:
    Nuclear Theory (nucl-th); Nuclear Experiment (nucl-ex)
    arXiv:
    2509.11794 [pdf]
    EPJ Web Conf.(2025)·0 citations

Affiliations

first authorsco-authorsvia INSPIRE