Near-threshold $K^*(892)^+$ meson production in the interaction of $\pi^-$ mesons with nuclei

Abstract

We study the inclusive strange vector meson $K^*(892)^+$ production in ${\pi^-}A$ reactions at near-threshold laboratory incident pion momenta of 1.4--2.0 GeV/c within a nuclear spectral function approach. The approach accounts for incoherent primary $\pi^-$ meson--proton ${\pi^-}p \to {K^*(892)^+}\Sigma^-$ production processes as well as the influence of the scalar $K^*(892)^+$--nucleus potential (or the $K^*(892)^+$ in-medium mass shift) on these processes. We calculate the absolute differential and total cross sections for the production of $K^*(892)^+$ mesons off carbon and tungsten nuclei at laboratory angles of 0$^{\circ}$--45$^{\circ}$ and at these momenta within five scenarios for the above shift. We show that the $K^*(892)^+$ momentum distributions and their excitation functions (absolute and relative) possess a high sensitivity to changes in the in-medium $K^*(892)^+$ mass shift in the low-momentum region of 0.1--0.6 GeV/c. Therefore, the measurement of such observables in a dedicated experiment at the GSI pion beam facility in the near-threshold momentum domain will allow to get valuable information on the $K^*(892)^+$ in-medium properties.