From controversy to precision on the sigma meson: a review on the status of the non-ordinary $f_0(500)$ resonance
By J. R. Peláez. 2015
371 citations recorded by the source corpus.
The existence and properties of the sigma meson have been controversial for almost six decades, despite playing a central role in the spontaneous chiral symmetry of QCD or in the nucleon-nucleon attraction. This controversy has also been fed by the strong indications that it is not an ordinary quark-antiquark meson. Here we review both the recent and old experimental data and the model independent dispersive formalisms which have provided precise determinations of its mass and width, finally settling the controversy and leading to its new name: $f_0(500)$. We then provide a rather conservative average of the most recent and advanced dispersive determinations of its pole position $\sqrt{s_\sigma}=449^{+22}_{-16}-i(275\pm12)$. In addition, after comprehensive introductions, we will review within the modern perspective of effective theories and dispersion theory, its relation to chiral symmetry, unitarization techniques, its quark mass dependence, popular models, as well as the recent strong evidence, obtained from the QCD $1/N_c$ expansion or Regge theory, for its non ordinary nature in terms of quarks and gluons.
Subfields: Nuclear and High Energy Physics
View Paper: https://www.semanticscholar.org/paper/d49efbee5ab4cc1e44ca974ba1546c4579deddd3
How researchers see this paper
The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.
In Nuclear and High Energy Physics
Citations in the corpus
- Dispersion relation for hadronic light-by-light scattering: two-pion contributions (2017, neutral): “We also checked that the σ properties [126] are reproduced: for the pole position we find √ sσ = (0.”
- Hadronic molecules (2017, background): “(Peláez, 2016).”
- The XYZ states: Experimental and theoretical status and perspectives (2019, background): “, potential models, it does not survive the large Nc limit: While nuclei should continue to exist in the large Nc limit [513], since a baryon contains Nc quarks and this adds to the multiplicity of the possible diagrams, mesonic molecules will most probably not [532].”
- Scattering processes and resonances from lattice QCD (2017, methodology): “It is only when amplitude forms which build in the required constraints of analyticity and crossing-symmetry are utilized that the pole position can be pinned down with precision (Caprini et al., 2006; Garcia-Martin et al., 2011; Pelaez, 2016).”