Coherent Production of theQandLMesons off Deuterium

Abundant production of the established $L$ meson and also of the possible $Q$ meson are observed in coherent production, $K^{-}d\to K^{-}{\pi }^{+}{\pi }^{-}d$, at 12.6 BeV/c. This is the first observation of $L$-meson production on nuclei. The $Q$ and $L$ isospins are unambiguously determined to be ½. The $L$ is observed to be produced polarized. A striking resemblance between the final states $K^{*}\mathrm{}\left(890\right)\mathrm{}\pi d$ and $K^{*}\mathrm{}\left(1400\right)\mathrm{}\pi d$ is observed with these final states being related to the $Q$ and $L$ mesons, respectively.