Updated astrophysical equation-of-state constraints on the color-superconducting gap

¹ Faculty of Science and Technology, University of Stavanger, 4036 Stavanger, Norway
² MIT Center for Theoretical Physics - a Leinweber Institute, Massachusetts Institute of Technology, Cambridge, MA 02139, USA

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Published online: 17 April 2026

Abstract

We summarize and update using new NICER measurements the results of Ref. [1], in which we used various astrophysical neutron-star observations to set an upper bound on the CFL color-superconducting gap in a range of baryon chemical potentials μ_B ∈ [2.1, 3.2], above those reached within neutron stars. We also corroborate the "reasonable" constraint from Ref. [1] on the maximum value of the color-superconducting gap by performing a new Bayesian analysis using a prior that extends a two-segment Gaussian process connecting the whole density range between CEFT and pQCD.