Now You See It, Now You Don't--The Pattern of Production of Certain   Resonances
  We try to motivate from QCD a pattern of production in various reactions of (non)exotic resonances. A higher penalty for extra q\bar{q} production in e^+ e^- collisions than in collisions with a nucleon target may explain the absence of exotic multi-quark states in e^+ e^- . We also briefly address the doubly-charmed baryons and the utilization of QCD inequalities in connection with possible new hadronic states. 
S. Nussinov