Everson H. Rodrigues | Searcharxiv

arXiv2026

Effects of short-range correlations at high densities on neutron stars with and without DM content: role of the repulsive self-interaction

In this work, we investigate how short-range correlations affect relativistic hadronic models at high densities, with direct consequences for the structure of neutron stars, both with and without dark matter content. Two versions of the model are examined: one with vector self-interactions up to second order ($ω_0^2$) and another including a fourth-order term ($ω_0^4$). We show that SRC tend to soften the equation of state when only the quadratic term is present, but produce a noticeable stiffening once the $ω_0^4$ term is included. The corresponding Tolman-Oppenheimer-Volkoff solutions for pure neutron stars indicate that short-range correlations reduce the maximum mass in the first case but increase it in the second. Extending the analysis to stars containing a fermionic dark matter component, within the two-fluid formalism, we verify that the same features appear in the respective mass-radius diagrams. In particular, the decrease of the maximum mass with increasing dark matter fraction is partly compensated by the SRC effects in the hadronic sector for the model with the fourth-order term. In all cases, the resulting parametrizations are consistent with recent astrophysical constraints, including the joint NICER-XMM-Newton analyses of the pulsars PSR J0030+0451 and PSR J0740+6620, as well as the gravitational-wave event GW190425.

nucl-th↗

arXiv2025

Strange stars admixed with dark matter: equiparticle model in a two fluid approach

In this work, we explore the possible scenario of strange stars admixed with fermionic or bosonic dark matter. For the description of the ``visible'' sector, we use a specific phenomenological quark model that takes into account in-medium effects for the quark masses through a suitable baryonic density dependence, in which the free parameters are chosen from the analysis of the stellar matter stability window (parametrizations presenting lower energy per baryon than iron nuclei). In the case of the dark sector, we investigate the predictions of fermionic and bosonic models. In the former, we consider a spin $1/2$ dark particle, and the latter is described by a dark scalar meson. Both models present a repulsive vector interaction, particularly important for the bosonic model since it helps avoid the collapse of the star due to the lack of degeneracy pressure. Our results point out possible stable strange stars configurations in agreement with data from the NASA NICER measurements of the pulsars PSR J0030+0451 and PSR J0740+6620, including the latest observational data, as well as the observed HESS J1731-347 mass-radius relationship. As another feature, we find stars with dark matter halo configurations for lower values of the dark particle mass.

astro-ph.HE↗