On the nature of the $\Lambda (1405)$ and $\Lambda (1670)$ from their $N_c$ behavior in chiral dynamics

Abstract

We study the behavior with the number of colors ($N_c$) of the $\Lambda (1405)$ and $\Lambda (1670)$ resonances obtained dynamically within the chiral unitary approach. The leading order meson-baryon interaction, used as the kernel of the unitarization procedure, manifests a nontrivial $N_c$ dependence of the flavor SU(3) representation for baryons. As a consequence, the SU(3) singlet (or $\bar{K}N$) component of the $\Lambda (1405)$ states remains bound in the large $N_c$ limit, while the other components dissolve into the continuum. Introducing explicit SU(3) breaking, we obtain the $N_c$ dependence of the excitation energy, masses and widths of the physical $\Lambda (1405)$ and $\Lambda (1670)$ resonance. The $N_c$ behavior of the decay width is found to be different from the general counting rule for a $qqq$ state, indicating the dynamical origin of these resonances.

29 pages, 8 figures

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• The role of the $\Lambda (1405)$ in the $pp\to p{K}^{+}\Lambda (1405)$ reaction
• Structure of the Lambda(1405) baryon resonance from its large Nc behavior
• Large Nc Weinberg-Tomozawa interaction and negative parity s--wave baryon resonances
• The radiative decay of the $\Lambda (1405)$ and its two-pole structure
• Exotic hadrons in s-wave chiral dynamics
• Five-quark picture of Lambda(1405) in anisotropic lattice QCD
• Hard hadron spectroscopy
• Remarks on N_c dependence of decays of exotic baryons
• Study of exotic hadrons in s-wave chiral dynamics

Cited by in corpus (11)

• Comprehensive analysis of the wave function of a hadronic resonance and its compositeness
• Interaction of vector mesons with baryons and nuclei
• Low-lying even parity meson resonances and spin-flavor symmetry
• Electromagnetic mean squared radii of Lambda(1405) in chiral dynamics
• Nature of the sigma meson as revealed by its softening process
• The nature of Lambda(1405) hyperon resonance in chiral dynamics
• Quark mass dependence of H-dibaryon in $\Lambda \Lambda$ scattering
• New insights into the nature of the $\Lambda (1380)$ and $\Lambda (1405)$ resonances away from the SU(3) limit
• Recent developments in antikaon-nucleon dynamics
• Interaction of vector mesons with baryons and vectors in the nuclear medium
• Chiral dynamics and baryon resonances