Theory Overview on Spectroscopy
  A theoretical overview of the exotic spectroscopy in the charm and beauty quark sector is presented. These states are unexpected harvest from the $e^+e^-$ and hadron colliders and a permanent abode for the majority of them has yet to be found. We argue that some of these states, in particular the $Y_b(10890)$ and the recently discovered states $Z_b(10610)$ and $Z_b(10650)$, discovered by the Belle collaboration are excellent candidates for tetraquark states   $[bq][\bar{b}\bar{q}]$, with $q=u,d$ light quarks. Theoretical analyes of the Belle data carried out in the tetraquark context is reviewed. 
Ahmed Ali (DESY)
hep-ph hep-ex