Precision dispersive approaches versus unitarized chiral perturbation theory for the lightest scalar resonances σ/f0(500)\sigma /f_0(500) and κ/K0(700)\kappa /K_0^*(700)

Jan 16, 2021
50 pages
Published in:
  • Eur.Phys.J.ST 230 (2021) 6, 1539-1574
  • Published: Jun 16, 2021
e-Print:
Report number:
  • JLAB-THY-21-3306

Citations per year

2020202120222023202402468
Abstract: (Springer)
For several decades, the σ/f0(500)\sigma /f_0(500) and κ/K0(700)\kappa /K_0^*(700) resonances have been subject to long-standing debate. Both their existence and properties were controversial until very recently. In this tutorial review, we compare model-independent dispersive and analytic techniques versus unitarized Chiral Perturbation Theory, when applied to the lightest scalar mesons σ/f0(500)\sigma /f_0(500) and κ/K0(700)\kappa /K_0^*(700) . Generically, the former have settled the long-standing controversy about the existence of these states, providing a precise determination of their parameters, whereas unitarization of chiral effective theories allows us to understand their nature, spectroscopic classification and dependence on QCD parameters. Here we review in a pedagogical way their uses, advantages and caveats.
Note:
  • Invited tutorial-review for European Physical Journal Special Topics. Final version to appear published. Expanded discussions and reference list. 50 pages
  • perturbation theory: chiral
  • resonance: scalar
  • unitarity
  • dispersion relation
  • quantum chromodynamics
  • scalar meson
  • f0(600)
  • kappa meson