Is a soft nuclear equation of state extracted from heavy-ion data incompatible with pulsar data?

TL;DR

This paper examines the apparent contradiction between heavy-ion collision data suggesting a soft nuclear equation of state and pulsar observations indicating a hard equation of state, proposing that different density regimes explain the discrepancy.

Contribution

It clarifies how different density regimes probed by pulsar and heavy-ion data reconcile the conflicting constraints on the nuclear equation of state.

Findings

Pulsar data favors a hard equation of state.

Heavy-ion collisions suggest a soft equation of state.

Different density regimes explain the apparent contradiction.

Abstract

We discuss the recent constraints on the nuclear equation of state from pulsar mass measurements and from subthreshold production of kaons in heavy-ion collisions. While recent pulsar data points towards a hard equation of state, the analysis of the heavy-ion data allows only for soft equations of state. We resolve the apparent contradiction by considering the different density regimes probed. We argue that future measurements of global properties of low-mass pulsars can serve as an excellent cross-check to heavy-ion data.