Coherent Production of High-Mass Meson States inπ+dCollisions at 13GeVc

Evidence is found for the coherent production of high-mass meson states in the 1.6- and 1.9-GeV mass regions. These states are observed, respectively, in the $3\pi$ and $5\pi$ systems produced in the reactions ${\pi }^{+}d\to d{\pi }^{+}{\pi }^{+}{\pi }^{-}$ and ${\pi }^{+}d\to d{\pi }^{+}{\pi }^{+}{\pi }^{+}{\pi }^{-}{\pi }^{-}$ at 13 $\frac{\mathrm{GeV}}{c}$. The spin and parity of the $3\pi$ state, identified as the $A_3$ meson, is determined to be in the series $2^{-},3^{+},\cdots$ with a dominant $f\pi$ decay.