Structure of the Lambda(1405) baryon resonance from its large Nc behavior

TL;DR

This paper investigates how the Lambda(1405) resonance's two poles behave as the number of colors (Nc) increases, revealing their dynamical origin and the persistence of the SU(3) singlet component in the large Nc limit.

Contribution

It provides a detailed analysis of the Nc dependence of the Lambda(1405) poles within the chiral unitary approach, highlighting their dynamical nature and the survival of the SU(3) singlet component.

Findings

The SU(3) singlet (Kbar N) component remains bound at large Nc.

Decay widths exhibit behavior different from qqq states, indicating a dynamical origin.

The two poles of Lambda(1405) are confirmed to be dynamically generated.

Abstract

We study the behavior with the number of colors (Nc) of the two poles associated to the Lambda(1405) resonance obtained dynamically within the chiral unitary approach. The leading order chiral meson-baryon interaction manifests a nontrivial Nc dependence for SU(3) baryons, which gives a finite attractive interaction in some channels in the large Nc limit. As a consequence, the SU(3) singlet (Kbar N) component of the Lambda(1405) survives in the large Nc limit as a bound state, while the other components dissolve into the continuum. The Nc dependence of the decay widths shows different behavior from the general counting rule for a qqq state, indicating the dynamical origin of the two poles for the Lambda(1405) resonance.