Comparing strange and non-strange quark stars within resummed QCD at NLO

TL;DR

This paper uses the RGOPT resummation method to evaluate the equation of state for strange and non-strange quark matter, deriving mass-radius relations for quark stars that align with observed pulsar data and exhibit reduced scale sensitivity.

Contribution

It introduces the application of RGOPT at NLO to compute quark star properties, providing a more stable and compatible alternative to perturbative QCD predictions.

Findings

RGOPT produces mass-radius curves compatible with observed pulsars.

The method shows less sensitivity to scale variations than pQCD.

Strange quark matter results in softer equations of state.

Abstract

We employ the renormalization group optimized perturbation theory (RGOPT) resummation method to evaluate the equation of state (EoS) for strange ($N_f=2+1$) and non-strange ($N_f=2$) cold quark matter at NLO. This allows us to obtain the mass-radius relation for pure quark stars and compare the results with the predictions from perturbative QCD (pQCD) at NNLO. Choosing the renormalization scale to generate maximum star masses of order $M=2 - 2.6 M_\odot$, we show that the RGOPT can produce mass-radius curves compatible with the masses and radii of some recently observed pulsars, regardless of their strangeness content. The scale values required to produce the desired maximum masses are higher in the strange scenario since the EoS is softer in this case. The possible reasons for such behavior are discussed. Our results also show that, as expected, the RGOPT predictions for the relevant observables are less sensitive to scale variations than those furnished by pQCD.