S-matrix approach to equation of state of nuclear matter

TL;DR

This paper develops an S-matrix based approach to calculate the nuclear matter equation of state, incorporating all relevant particles and scattering channels, leading to improved convergence at higher densities.

Contribution

It introduces a comprehensive, model-independent virial series for nuclear matter pressure that includes higher mass particles and multi-particle scattering channels.

Findings

The virial series converges at higher baryon densities than previous models.

Heavy particles and their scattering channels significantly impact the equation of state.

The approach systematically accounts for resonances in all scattering channels.

Abstract

We calculate the equation of state of nuclear matter based on the general analysis of the grand canonical partition function in the $S$-matrix framework. In addition to the low mass stable particles and their two-body scattering channels considered earlier, the calculation includes systematically all the higher mass particles and their exited states as well as the scattering channels formed by any number of these species. We estimate the latter contribution by resonances in all the channels. The resulting model-independent virial series for pressure gets substantial contribution from the heavy particles and the channels containing them. The series converges for larger values of baryon density than found earlier.