Near-threshold K^*(892)⁺ meson production in the interaction of π⁻ mesons with nuclei

Abstract

We study the inclusive production of strange vector mesons in reactions at near-threshold laboratory incident pion momenta of 1.4–2.0 GeV/c via a nuclear spectral function approach. The approach accounts for incoherent primary meson–proton production processes as well as the influence of the scalar –nucleus potential (or the in-medium mass shift) on these processes. We calculate the absolute differential and total cross sections for the production of mesons from carbon and tungsten nuclei at laboratory angles of 0 –45 and at the aforementioned momenta in five scenarios for the aforenoted shift. We show that the momentum distributions and their excitation functions (absolute and relative) possess a high sensitivity to changes in the in-medium 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 us to get valuable information on the in-medium properties.

Vector mesons in medium

“…The production of both K * , K 1 will be possible by the Kaon beam at JPARC, and K * by the pion beam at GSI [19]. If chiral symmetry is restored, the degeneracy of K * , K 1 mass will lead to similar numbers for the production of these partners at the hadronization point in a heavy ion collision.…”