It is suggested that the recently reported charged charmoniumlike resonance Zc(4100) and the previously observed Zc(4200) are two states of hadrocharmonium, related by the charm quark spin symmetry in the same way as the lowest charmonium states ηc and J/ψ. Namely, the Zc(4100) is (dominantly) the ηc embedded in a light-quark excitation with quantum numbers of a pion, while the Zc(4200) is a similar four quark state containing J/ψ instead of ηc. It is argued that this picture suggests certain relations between the properties of the two exotic resonances and a distinctive pattern of their decays that can be tested experimentally. It is also pointed out that due to the presence of a spatially compact cc charmonium the discussed exotic Zc states may be produced as resonances in the s channel in pp annihilation.
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This work is supported in part by U.S. Department of Energy Grant No. DE-SC0011842.
© 2018 authors. Published by the American Physical Society.