Exotic mesons, locking states and their role in the formation of the   confinement barrier
  We discuss a mechanism by which a set of $q\bar q$-states mixes with an exotic one, so that the exotic state accumulates the widths of the overlapping $\bar qq$ resonances. The broad state created this way acts as a 'locking' state for the others. Using results of a previous analysis of the $(IJ^{PC}=00^{++})$-wave, we estimate the mean radius squared of the broad state $f_0 (1530^{+90}_{-250})$; it appears to be distinctly larger than the mean squared radii of the locked narrow states. This supports an idea about the constructive role of broad states in forming the confinement barrier. 
V. V. Anisovich (1), D. V. Bugg (2), A. V. Sarantsev (1) ((1)   St.Petersburg Nuclear Physics Institute, (2) Queen Mary and ...