The new narrow resonance which has been observed at the B factories is assigned to the I_z=0 component of iso-triplet charmed four-quark mesons, and as its consequence, existence of additional narrow resonances in different channels is predicted.
Cite
@article{arxiv.hep-ph/0309119,
title = {BABAR Resonance and Four-quark Mesons},
author = {K. Terasaki},
journal= {arXiv preprint arXiv:hep-ph/0309119},
year = {2007}
}