An international group of physicists has concluded that there is an 80-90% chance that the most massive neutron stars have an ultra-dense, dispersed quark matter at their cores. The researchers used Bayesian inference to analyze observations of neutron stars and came to this conclusion. Quantum field theory suggests that at extreme temperatures and pressures, quarks and gluons, unlike protons, neutrons, and other hadrons, are no longer strongly coupled. Instead, they can exist independently in an exotic quark-gluon plasma known as unconfined quark matter. This state of matter is thought to have dominated the universe in the first moments after the Big Bang. They have also been created temporarily in experimental environments such as the Large Hadron Collider. A neutron star is a collapsed star core with a mass greater than that of the Sun concentrated in an object with a radius of only 10 to 20 km. The density of a neutron star increases from the crust to the core, where electrons and protons are squeezed together to form mostly neutron material.

The nuclei of the heaviest ones contain 80-90% unconsolidated quark matter, which is high, but scientists’ findings have not yet been confirmed. The remaining 10-20% probability corresponds to a scenario in which all neutron stars are composed entirely of nuclear matter, requiring a strong first-order phase transition between nuclear and quark matter. This study raises many new questions from an astrophysical perspective. There is also interest in the possible influence of this state of matter on various astrophysical phenomena. The researchers plan to examine the research question in more detail in the future.

source: https://www.nature.com/articles/s41467-023-44051-y