Single-Pion Production by 1.96-BeVcK+Mesons

Abstract

Single-pion production by $K^{+}$ mesons at a momentum of 1.96 $\frac{\mathrm{BeV}}{c}$ is shown to lead predominantly to $K^{*}p$ and $N^{*}K$ final states. Study of the dynamics of the reaction shows that the $N^{*}K$ final state is produced almost entirely via vector exchange, whereas the $K^{*}p$ final state seems to be produced partly via pion exchange and partly via vector exchange. Numerical values in terms of Gottfried and Jackson's parametrization of the spin-density matrix are given for the $K^{*}p$ final state. Comparison with similar analyses at energies below and above this experiment indicates that a strong energy dependence of the vector-meson exchange contributes to the $K^{*}p$ production. We show that the form factors used to fit the vector-meson-exchange contribution to these processes at 3 $\frac{\mathrm{BeV}}{c}$ do not fit the data at this energy.