Polarization of Λ hyperons produced by the quasifree (π^{+},K^{+}) reaction on ^{12}C

The polarization of quasifree Λ hyperons produced by the (${\mathrm{\pi }}^{+}$ ${\mathit{K}}^{+}$) reaction on ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ and on the deuteron was measured for the first time. The asymmetry of pions from weak decay of the Λ hyperon was used to determine the polarization. The polarization for the deuterium target was found to be consistent with that for the elementary n(${\mathrm{\pi }}^{+}$,${\mathit{K}}^{+}$)Λ reaction. The polarization of the Λ produced by the quasifree process from ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ is consistent with that for the elementary reaction, which demonstrates that the spin characteristics of the elementary reaction are not modified by the nuclear medium.