Why hybrid meson coupling to two S-wave mesons is suppressed

We introduce strong interaction selection rules for the two-body decay and production of hybrid and conventional mesons coupling to two S-wave hybrid or conventional mesons. The rules arise from symmetrization in states in the limit of non-relativistically moving quarks. The conditions under which the connected coupling of a hybrid to two S-wave hybrid or conventional mesons is suppressed are determined by the rules, and the nature of their breaking is indicated.