Lightest scalars as chiral partners of the Nambu--Goldstone bosons

Abstract

We review the spectrum of lightest scalar resonances recently determined using dispersion techniques. The conceptual difference between the pole mass and the bare mass (or the line--shape mass) is stressed. The nature of the lightest scalars are discussed and we argue, without relying on any model details, that the $\sigma (500)$, $\kappa (700)$, $a_0(980)$ and $f_0(980)$ may be understood as chiral partners of the Nambu--Goldstone bosons in the linear realization of chiral symmetry. But there remains some difficulties in understanding the role of $f_0(980)$ in this picture.

arXiv commentInvited talk given by Zheng at QCD06, Montpellier, France, July 3--7, 2006

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• Unitarized pseudoscalar meson scattering amplitudes in three flavor linear sigma models
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Cited by in corpus (5)

• Glueball nature of the sigma/f_0(600) from pi-pi and gamma-gamma scatterings
• Gluonium nature of the sigma/f_0(600) from its coupling to KK
• The sigma and f_0(980) from Ke4 + pi-pi scatterings data
• Pole Analysis of Unitarized One Loop $\chi$PT Amplitudes - A Triple Channel Study
• Low Lying Scalar Resonances and Chiral Symmetry