Can low-lying Roper states be explained as antidecuplet members?

It is shown that the anomalously low-lying Roper states cannot be assigned as pentaquarks with the scalar diquark - scalar diquark - antiquark structure as suggested by Jaffe and Wilczek.Comment: Will appear in Phys. Rev. Lett. as a comment on the paper by R. Jaffe and F. Wilczek, Phys. Rev. Lett., 91, 232003 (2003

Why the OZI rule is so strongly violated in J/Psi decays?

The new $f_0(1790)$ meson recently observed by BES collaboration in $J/\Psi$-decay, is seen only in the OZI-forbidden channel. It is shown that chiral symmetry restoration in excited hadrons implies a new selection rule of dynamical origin that forbids some of the OZI-favoured mechanisms of decays. Hence decays into channels that are suppressed by OZI can become dominant.Comment: 5 pages, 5 figures. The paper has been expanded. A new figure as well as implications of chiral symmetry for the search of missing a_0 mesons in charmonium decays have been added. To appear in Phys. Rev.