Fall-apart decays of polyquark hadrons

We analyze fall-apart decays of polyquark (tetra, penta and molecule type) hadrons within the constituent quark picture. For processes in which a polyquark hadron goes to final states containing a light pseudoscalar meson the constraints given by chiral symmetry are implemented. As an application of the approach developed, fall-apart decays of a(980) and X(3872) are studied, assuming these mesons are polyquark hadrons. Two extreme options--confined diquark-diquark states and molecular states--are considered. For a0(980), the observed width can be obtained assuming that this meson is a diquark-diquark composite with a relatively large size of around 1 divide 1.5 fm. The pure KK molecular-type state, however, can be excluded. For the X(3872), a sufficiently small width can be obtained if it is a dominantly isospin-0 diquark-diquark composite with a very large size of ≥2.5 fm. The pure molecular option appears possible if the binding energy is tiny, Eb < or approx. 0.2 MeV, corresponding to a huge size