On Deusons or Deuteronlike Meson-Meson Bound States

Abstract

The systematics of deuteronlike two-meson bound states, {\it deusons}, is discussed. Previous arguments that many of the present non-$q\bar{q}$ states are such states are elaborated including, in particular, the tensor potential. For pseudoscalar states the important observation is made that the centrifugal barrier from the P-wave can be overcome by the $1/r^2$ and $1/r^3$ terms of the tensor potential. In the heavy meson sector one-pion exchange alone is strong enough to form at least deuteron-like $B{\bar{B}}^{\ast }$ and $B^{\ast }{\bar{B}}^{\ast }$ composites bound by approximately 50 MeV, while $D{\bar{D}}^{\ast }$ and $D^{\ast }{\bar{D}}^{\ast }$ states are expected near the threshold.

Comments: Invited talk at the Hadron93 International Conf. on Hadron Spectroscopy, Como, Italy 22.-25.6. 1993. 5 pages in LATEX HU-SEFT R 1993-13b