Inclusive production of $K_1^0$, ${\Lambda }^0$, and ${\Lambda }^0$ in $18.5-\frac{\mathrm{GeV}}{c} {\pi }^{\pm }p$ interactions

Data are presented for the single-particle inclusive reactions ${\pi }^{\pm }p\to K_1^0+$ anything, ${\pi }^{\pm }p\to {\Lambda }^0+$ anything, and ${\pi }^{\pm }p\to {\overline{\Lambda }}^0+$ anything at 18.5 $\frac{\mathrm{GeV}}{c}$. We have studied the invariant cross section $\frac{E{d}^3\sigma }{d\overrightarrow{\mathrm{p}}}$ in terms of the variables ($P_L,{P_T}^2$), ($x,{P_T}^2$), ($y,{P_T}^2$), and ($y_r,{P_T}^2$). The distributions for the longitudinal-momentum variable depend strongly on the type of particle produced. The $K_1^0$ distributions are not symmetric about $x=0\mathrm{}$, where $x$ is the Feynman scaling variable; more $K_1^0$'s are produced in the forward hemisphere, suggestive of beam fragmentation. The ${\Lambda }^0$ distributions peak in the backward hemisphere, suggestive of target fragmentation. The ${\overline{\Lambda }}^0$ distributions are significantly different from the ${\Lambda }^0$ distributions. Distributions of transverse momentum are fitted with the function $A{e}^{-B{P_T}^2}$. The average transverse momentum of the $K_1^0$, ${\Lambda }^0$, and ${\overline{\Lambda }}^0$ increases logarithmically with the mass of the produced particle. Topological cross sections and multiplicity distributions are presented. We have studied the ${\Lambda }^0$ polarization as a function of $|t-t_{min}|$, $x$, and charge multiplicity. We find that the ${\pi }^{-}p$ data show a significant polarization for $0.5\le |t-t_{min}|\le 1.5 {\left(\frac{\mathrm{GeV}}{c}\right)}^2$ and for $-0.8\mathrm{}\le x\le -0.4\mathrm{}$, while in the ${\pi }^{+}p$ data the polarization is everywhere consistent with zero.