Two, three, many body systems involving mesons

TL;DR

This paper discusses recent advances in few-body meson systems using chiral dynamics, simplifying calculations by focusing on on-shell amplitudes and exploring various meson and meson-baryon states.

Contribution

It introduces an approach to Faddeev equations that cancels off-shell contributions, enabling unambiguous calculations with on-shell two-body amplitudes and studies multiple meson systems.

Findings

Reproduces properties of low-lying $1/2^+$ states with meson-baryon systems.

Identifies multirho and $K^*$ multirho states related to known high-spin meson resonances.

Demonstrates the effectiveness of on-shell methods in few-body meson physics.

Abstract

In this talk we show recent developments on few body systems involving mesons. We report on an approach to Faddeev equations using chiral unitary dynamics, where an explicit cancellation of the two body off shell amplitude with three body forces stemming from the same chiral Lagrangians takes place. This removal of the unphysical off shell part of the amplitudes is most welcome and renders the approach unambiguous, showing that only on shell two body amplitudes need to be used. Within this approach, systems of two mesons and one baryon are studied, reproducing properties of the low lying $1/2^+$ states. On the other hand we also report on multirho and $K^*$ multirho states which can be associated to known meson resonances of high spin.