Neutron Star Equation of State with Nucleon Short-Range Correlations: A Concise Review and Open Issues

TL;DR

This paper reviews how nucleon short-range correlations and high-momentum tails influence the nuclear matter equation of state and neutron star properties, highlighting current findings and open research questions.

Contribution

It provides a concise overview of SRC effects on the nuclear EOS and neutron star observables, emphasizing recent results and future open issues.

Findings

SRCs significantly modify the kinetic part of the EOS.

High-momentum tails impact neutron star mass-radius relations.

Current observations constrain SRC-related models.

Abstract

Nucleon short-range correlations (SRCs) and the associated high-momentum tail (HMT) in its momentum distribution $n(k)$ represent a universal feature of strongly interacting Fermi systems. In nuclear matter, SRCs arise primarily from the spin-isospin dependence of the tensor and short-range components of the nucleon-nucleon interaction, leading to a substantial depletion of its Fermi sea and a characteristic $k^{-4}$ tail populated predominantly by isosinglet neutron-proton pairs. These microscopic structures modify both the kinetic and interaction contributions to the Equation of State (EOS) of dense matter and thereby influence a broad range of neutron-star (NS) properties. This short review provides a streamlined overview of how SRC-induced changes in $n(k)$ reshape the kinetic EOS, including its symmetry energy part and how these effects propagate into macroscopic NS observables, including mass-radius relations, tidal deformabilities, direct Urca thresholds and core-crust transition. We summarize key existing results, highlight current observational constraints relevant for testing SRC-HMT effects, and outline open questions for future theoretical, experimental, and multimessenger studies of dense nucleonic matter.