Thermodynamics of the strange baryon system from a coupled-channels analysis and missing states

Abstract

We study the thermodynamics of the strange baryon system by using an S-matrix formulation of statistical mechanics. For this purpose, we employ an existing coupled-channel study involvinḡ KN , πΛ, and πΣ interactions in the S = −1 sector. A novel method is proposed to extract an effective phase shift due to the interaction, which can subsequently be used to compute various thermal observables via a relativistic virial expansion. Using the phase shift extracted, we compute the correlation of the net baryon number with strangeness (χBS) for an interacting hadron gas. We show that the S-matrix approach, which entails a consistent treatment of resonances and naturally incorporates the additional hyperon states which are not listed by the Particle Data Group, leads to an improved description of the lattice data over the hadron resonance gas model.

Thermal contribution of unstable states

“…So far we have restricted our discussion to Fock space up to two body. It will be extremely interesting to extend the scheme to include multi-channel and multi-body scatterings [13,21,56,84,85], and understand how these interactions would influence thermodynamic quantities. This can be a useful framework to analyze the observables in Heavy Ion Collision experiments, such as hadron yields and the momentum distributions of light hadrons [61,[86][87][88].…”

Thermal properties of S = − 1 Hyperons: an S-matrix approach

“…To describe a coupled-channel system, we consider the following generalization to a singlechannel phase shift [14,19]:…”

Bose-Einstein condensation phenomenology in systems with repulsive interactions

“…Influence of particle interactions on the thermodynamic properties was also considered within the S-matrix formulation of statistical mechanics [27]. In particular, the attractive and repulsive interaction from pion-pion and other hadron-hadron scatterings were discussed in a number of works [28][29][30][31].…”