We assume that the newly discovered mesons $\psi \mathrm{}\left(3.1\right)\mathrm{}$ and $\psi \mathrm{}\left(3.7\right)\mathrm{}$ are nonrelativistic bound states of charmed quarks, and show that available data are consistent with this picture. We calculate the diffractive production of $\psi$ in the processes $\gamma A\to \psi A$ and $\mu A\to \mu \psi A$, where $A$ is a proton or nucleus, and find a result which is different from the vector-meson-dominance prediction. We also calculate the reactions $\nu \left(\overline{\nu }\right)A\to \mu \left(\overline{\mu }\right)F^{*}A$, where $F^{*}$ denotes the hypothetical particle with both charm and strangeness which is predicted by the SU(4) model. Our result appears to be compatible with the excess of events (compared to the parton model) seen in the inclusive reactions $\nu A\to {\mu }^{-}X$ and $\overline{\nu }A\to {\mu }^{+}X$.

• Received 21 April 1975

DOI:https://doi.org/10.1103/PhysRevD.12.1376