Quark and hybrid stars with renormalization group improvement of NNLO perturbative QCD
Abstract
Recently, the NNLO perturbative QCD pressure of cold and dense symmetric matter, with arbitrary quark masses, has been resummed within the renormalization-group-optimized perturbation theory (RGOPT) framework. By being imbued with renormalization group properties, the resulting pressure is less sensitive to renormalization scale (Λ≡ X μB/3) variations than the NNLO perturbative QCD pressure. Here, we extend this by considering β-equilibrium and charge neutrality to evaluate the corresponding equation of state (EoS). We provide a compact ``pocket" fitting formula for the EoS for Nf=2+1 massive quarks at different renormalization scale parameter (X) values. We describe pure quark stars as well as hybrid stars with quark-cores. Pure quark stars compatible with astrophysical observations were obtained with X=2.71−3.30, whereas a larger value (3.84) is needed if the secondary component of the observation GW190814 represents a neutron star. Hybrid stars were built considering three representative hadron models based on a relativistic mean-field description, and chosen to produce soft and stiff EoSs. Stable hybrid stars with masses compatible with the massive pulsar PSR J0740+6620 were obtained considering X of the order of 2 to $2.71$, the largest scale giving rise to hybrid stars with a large quark core with a radius of 2 to 8 km , and the smallest to a small quark core at the center of the star.
Related
- Stability and Structural Properties of Hot Quark Stars within Perturbative QCD
- Astrophysical Constraints on Hadron--Quark Crossover in Hybrid Neutron Stars
- Axion effects on hybrid stars: earlier hadron-quark phase transition and larger quark-matter cores
- Axion effects on hybrid stars: earlier hadron-quark phase transition and larger quark-matter cores
- Universal relations for hybrid stars and their quark cores: a systematic scan of the quark-matter parameter space
BibTeX
@misc{fernandez2026quark,
title = {{Quark and hybrid stars with renormalization group improvement of NNLO perturbative QCD}},
author = {Loïc Fernandez and Jean-Loïc Kneur and Marcus Benghi Pinto and Constança Providência and Claudia Ratti and Tulio E. Restrepo},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2606.29576},
eprint = {2606.29576},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2606.29576},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Quark and hybrid stars with renormalization group improvement of NNLO perturbative QCD
AU - Loïc Fernandez
AU - Jean-Loïc Kneur
AU - Marcus Benghi Pinto
AU - Constança Providência
AU - Claudia Ratti
AU - Tulio E. Restrepo
PY - 2026
DA - 2026/10/07
PB - arXiv
DO - 10.48550/arxiv.2606.29576
UR - https://arxiv.org/abs/2606.29576
AB - Recently, the NNLO perturbative QCD pressure of cold and dense symmetric matter, with arbitrary quark masses, has been resummed within the renormalization-group-optimized perturbation theory (RGOPT) framework. By being imbued with renormalization group properties, the resulting pressure is less sensitive to renormalization scale (Λ≡ X μ_B/3) variations than the NNLO perturbative QCD pressure. Here, we extend this by considering β-equilibrium and charge neutrality to evaluate the corresponding equation of state (EoS). We provide a compact ``pocket" fitting formula for the EoS for N_f=2+1 massive quarks at different renormalization scale parameter (X) values. We describe pure quark stars as well as hybrid stars with quark-cores. Pure quark stars compatible with astrophysical observations were obtained with X=2.71−3.30, whereas a larger value (3.84) is needed if the secondary component of the observation GW190814 represents a neutron star. Hybrid stars were built considering three representative hadron models based on a relativistic mean-field description, and chosen to produce soft and stiff EoSs. Stable hybrid stars with masses compatible with the massive pulsar PSR J0740+6620 were obtained considering X of the order of 2 to $2.71$, the largest scale giving rise to hybrid stars with a large quark core with a radius of 2 to 8 km , and the smallest to a small quark core at the center of the star.
ER -