The XYZ's of c\bar{c}: Hints of Exotic New Mesons

Abstract

I discuss the nature of the new charm and charmonium like states observed in the last few years and measurements that can test these assignments. In particular it appears that the X(3943) is the eta_c''(3^1S_0) which can be tested by looking for it in gamma gamma to D\bar{D}^*, the Y(3943) is the chi_{c1}'(2^3P_1) which can be tested by looking for it in D\bar{D} and D\bar{D}^*, the Z(3930) is the chi_{c2}'(2^3P_2) which can be confirmed by looking for it in D\bar{D}^*. If the X(3872) is confirmed to have J^{PC}=1^{++} it is almost certainly a multiquark state while if its J^{PC} is found to be 2^{-+} is is likely the 1^1D_2 state. The Y(4260) appears to be an extra 1^{--} which is most easily explained as a charmonium hybrid. This can be tested by looking the DD_1 final state.