The nucleon and the two solar mass neutron star

TL;DR

This paper explores how a stiff equation of state, supported by nucleons as constituents, can explain the existence of a 2 solar mass neutron star, with implications for the strong interaction phase diagram.

Contribution

It demonstrates that a nucleon-based ground state can sustain high densities, supporting massive neutron stars and affecting the understanding of the strong interaction phase diagram.

Findings

Nucleons as constituents allow a stiff equation of state.

A purely nucleon ground state may exist up to four times nuclear density.

Implications for the strong interaction μ_B vs T phase diagram.

Abstract

The existence of a star with such a large mass means that the equation of state is stiff enough to provide a high enough pressure up to a fairly large central densities,. Such a stiff equation of state is possible if the ground state has nucleons as its constituents. This further implies that a purely nucleon ground state may exist till about four times nuclear density which indicates that quarks in the nucleon are strongly bound and that the nucleon nucleon potential is strongly repulsive. We find this to be so in a chiral soliton model for the nucleon which has bound state quarks. We point out that this has important implications for the strong interaction $ \mu_B$ vs T phase diagram.