Using the Beth-Uhlenbeck approach to describe the kaon to pion ratio in a 2+1 flavor PNJL model

TL;DR

This paper uses the Beth-Uhlenbeck approach within a 2+1 flavor PNJL model to analyze the kaon to pion ratio, highlighting the emergence of an additional bound state mode affecting experimental observations.

Contribution

It introduces a novel application of the Beth-Uhlenbeck approach to interpret medium modifications of meson states in a PNJL model, explaining the 'horn' effect in particle ratios.

Findings

Identification of an additional low-energy mode in the K+ channel.

Explanation of the 'horn' effect in K+/pi+ ratio.

Comparison with experimental data supports the model's predictions.

Abstract

The kaon to pion ratios are discussed in the framework of a 2+1 flavor PNJL model. In order to interpret the behaviour of bound states in medium the Beth-Uhlenbeck approach is used. It is shown that in terms of phase shifts in the K+ channel an additional low-energy mode could appear as a bound state in medium since the masses of the quark constituents are different. The comparison with experimental data for the ratios is performed and the influence of the anomalous mode to the "horn" effect in the K+/pi+ ratio is discussed.