We present results from an isobar‐model partial wave analysis of a high statistics sample of the neutral 3π system produced in forward charge exchange. Large forward phase motions relative to an exotic reference wave are seen for partial waves with the quantum numbers of the A1 and of the previously unobserved H mesons.

Results are presented from an isobar-model partial-wave analysis of a high-statistics sample of the neutral $3\ensuremath{\pi}$ system produced in forward charge exchange. Large forward phase motions relative to an exotic reference wave are seen for partial waves with the quantum numbers of the ${A}_{1}$ and of the previously unobserved isoscalar companion ($``H''$) of the $B(1235)$.

We present the first results from an isobar-model phase-shift analysis of the $\ensuremath{\eta}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ system. The $D(1275)$ meson is established as a narrow ($\ensuremath{\Gamma}\ensuremath{\sim}10$ MeV) $I{J}^{P}={01}^{+}$ resonance. Beneath the $D$ is a broader ($\ensuremath{\Gamma}\ensuremath{\sim}70$ MeV) $I{J}^{P}={00}^{\ensuremath{-}}$ state which is a candidate for the radially excited $\ensuremath{\eta}$. The data are consistent with the existence of another 0${0}^{\ensuremath{-}}$ object of comparable width near 1.4 GeV.

We present the first results from an isobar-model phase-shift analysis of the $\ensuremath{\eta}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ system. The $D(1275)$ meson is established as a narrow ($\ensuremath{\Gamma}\ensuremath{\sim}10$ MeV) $I{J}^{P}={01}^{+}$ resonance. Beneath the $D$ is a broader ($\ensuremath{\Gamma}\ensuremath{\sim}70$ MeV) $I{J}^{P}={00}^{\ensuremath{-}}$ state which is a candidate for the radially excited $\ensuremath{\eta}$. The data are consistent with the existence of another 0${0}^{\ensuremath{-}}$ object of comparable width near 1.4 GeV.

Differential cross sections are presented for the reactions ..pi../sup -/p ..-->.. B/sup 0/ (1235)n, B/sup 0/ ..-->.. ..omega../sup 0/..pi../sup 0/ (..omega../sup 0/ ..-->.. ..pi../sup +/..pi../sup -/..pi../sup 0/), and ..pi../sup -/p ..-->.. D/sup 0/ (1285)n, D/sup 0/ ..-->.. eta/sup 0/ ..pi../sup +/..pi../sup -/ (eta/sup 0/ ..-->.. ..gamma gamma..) at 8.45 GeV/c. The data were obtained at the Argonne ZGS with the Charged and Neutral Spectrometer which detected both charged pions and all ..gamma.. rays in these final states.

The first results from an isobar-model phase shift analysis of the eta..pi../sup +/..pi../sup -/ system are presented. Particular emphasis is given to an unambiguous determination of the spin-parity of the D(1285) meson.

We have obtained 68\ifmmode\pm\else\textpm\fi{}9 events of the previously unseen radiative decay ${\ensuremath{\eta}}^{\ensuremath{'}}\ensuremath{\rightarrow}\ensuremath{\omega}\ensuremath{\gamma}$ ($\ensuremath{\omega}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{0}$, ${\ensuremath{\pi}}^{0}\ensuremath{\rightarrow}\ensuremath{\gamma}\ensuremath{\gamma}$) in a charged- and neutral-particle spectrometer. Simultaneously, 1505 events of the decay ${\ensuremath{\eta}}^{\ensuremath{'}}\ensuremath{\rightarrow}\ensuremath{\eta}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ ($\ensuremath{\eta}\ensuremath{\rightarrow}\ensuremath{\gamma}\ensuremath{\gamma}$) were collected in the same apparatus, allowing a direct measurement of this branching ratio. We find $\frac{({\ensuremath{\eta}}^{\ensuremath{'}}\ensuremath{\rightarrow}\ensuremath{\omega}\ensuremath{\gamma})}{({\ensuremath{\eta}}^{\ensuremath{'}}\ensuremath{\rightarrow}\ensuremath{\eta}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}})}=(6.8\ifmmode\pm\else\textpm\fi{}1.3)%$ and use published data to derive $\frac{({\ensuremath{\eta}}^{\ensuremath{'}}\ensuremath{\rightarrow}\ensuremath{\rho}\ensuremath{\gamma})}{({\ensuremath{\eta}}^{\ensuremath{'}}\ensuremath{\rightarrow}\ensuremath{\omega}\ensuremath{\gamma})}=9.9\ifmmode\pm\else\textpm\fi{}2.0$, in excellent agreement with predictions based on vector meson dominance.

The reaction ..pi../sup -/p ..-->.. ..pi../sup +/..pi../sup -/..gamma gamma..n is studied with high statistics at 8.5 GeV with a charged and neutral particle spectrometer. Both charged pions and both ..gamma..'s are detected. A search was made for the ..pi../sup +/..pi../sup -/..pi../sup 0/ decays of the neutral A/sub 1/ and the two missing isoscalar companions of the B, and are seeking to clarify the status of the D and E mesons in ..pi../sup +/..pi../sup -/eta.

A search is made for the hitherto unobserved neutral J/sup P/ = 1/sup +/ objects A/sub 1//sup 0/ and H/sup 0/ produced in the reaction ..pi../sup -/p ..-->.. ..pi../sup +/..pi../sup -/..pi../sup 0/ ..-->.. ..gamma gamma.. n at 8.4 GeV/c. Both charged pions and both ..gamma..'s are measured in the Charged and Neutral Spectrometer at the Argonne ZGS. Preliminary results from a first-pass analysis of 45 percent of the data, containing approximately 900 events/10MeV/c/sup 2/ mass bin at 1100 MeV/c/sup 2/ are reported. Strong peaks at the eta, ..omega.., A/sub 2/, and ..omega..(1670) dominate the spectrum. The possible presence of less prominent structure is discussed.

Preliminary results are reported from a study of ..pi../sup -/p ..-->.. eta..pi../sup +/..pi../sup -/n (eta ..-->.. ..gamma gamma..) at 8.4 GeV/c, using the charged and neutral spectrometer at the Argonne ZGS. Both charged particles and both ..gamma..'s are measured by the apparatus. The data presented from a first-pass analysis of 45 percent of the sample, contain 1,770 eta' (958), 240 D(1285) and a suggestion of E(1420). Cascade decays via sigma(980) ..-->.. eta..pi.. will be discussed. A very clean sample of D(1285) is obtained by a suitable eta..pi.. mass cut.