We present a model-independent amplitude analysis of the reaction $K^{+}{n}_{\uparrow }\to K^{+}{\pi }^{-}P$ at 5.98 GeV/c using Saclay data obtained with a transversely polarized deuteron target at the CERN Proton Synchrotron. The analysis makes use of the data in two sets of binnings to examine the dependence of amplitudes on momentum transfer $t[-t\le 1.0{(\frac{\mathrm{GeV}}{c}}^2]$ in the $K^{*0\mathrm{}}$ mass region, and their dependence on $K^{+}{\pi }_{-}$ invariant mass below 1000 MeV for momentum transfers $-t=0.2-0.4\mathrm{}$ ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^2$. The analysis is performed in both $t$-channel and $s$-channel helicity frames of the dimeson state. The data yield two solutions for 8 moduli and 6 cosines of relative phases of nucleon transversity amplitudes with dimeson spins $J=0\mathrm{}$ ($S$ wave) and $J=1\mathrm{}$ ($P$ wave). The two solutions differ mainly in the contributions of the $S$ wave. Both solutions require nonzero nucleon helicity-flip amplitudes. The differences in the moduli of the amplitudes with a recoil nucleon transversity "up" and "down" reveal the essential role of nucleon spin in the pion production process. The $P$-wave moduli show unexpected structures within the $K^{*0\mathrm{}}$ mass range which provide new information on $K^{*0\mathrm{}}$ production. The mass dependence of solution 2 suggests the possible existence of a scalar state $I=\frac{1}{2}{0}^{+} \mathrm{}\left(887\right)\mathrm{}$ with a width of about 20 MeV. We comment on its possible constituent structure. Our results emphasize the need for a systematic study of pion production on the level of amplitudes in a new generation of dedicated experiments with spin at the recently proposed advanced hadron facilities.

• Received 10 June 1991

DOI:https://doi.org/10.1103/PhysRevD.45.1518