Meson spectroscopy: too much excitement and too few excitations

Abstract

We briefly review the general status of meson spectroscopy, especially in light of the often made claim that there are too many observed resonances to be accounted for as $q\bar{q}$ states. Also, the adequacy of the usual Coulomb-plus-linear, alias "funnel", confining potential for reproducing the experimental spectra of light, heavy-light, and heavy mesons is critically analysed. Thus, many serious discrepancies are observed and discussed. As possible causes, we suggest the neglect of unitarisation and other coupled-channel effects, as well as the deficiency of the funnel potential itself. In order to illustrate our alternative, "unquenched" approach, we present some recent examples of successfully described puzzling mesonic enhancements and resonances, such as the charmonium states X(4260) and X(3872), as well as the axial-vector charmed mesons $D_1(2420)$, $D_1(2430)$, $D_{s1}(2536)$, and $D_{s1}(2460)$.

Contribution to the International Meeting "Excited QCD", Peniche, Portugal, 06 - 12 May 2012; 8 pages, 3 figures (5 plots), Acta Physica Polonica style

References in corpus (2)

• Exes and why Z? Some charming and beautiful observations
• Comment on "Observation of a New chi_b State in Radiative Transitions to Upsilon_1S and Upsilon_2S at ATLAS"

Cited by in corpus (4)

• The $XYZ$ states: experimental and theoretical status and perspectives
• Phenomenology of axial-vector and pseudovector mesons: decays and mixing in the kaonic sector
• The role of the next-to-leading order triangle-shaped diagram in two-body hadronic decays
• The scalar-isovector sector in the extended Linear Sigma Model