Probing the antikaon potential by K$^-$A elastic scattering

Abstract

We extract the antikaon potential from differential data on elastic $K^-A$ scattering within Glauber theory at an antikaon momentum of 800 MeV/c. The $K^-N$ cross section at densities up to 0.1 $fm^3$ is found to be close to the value given in free space $K^-p$ and $K^-n$ interactions (averaged over the number of protons and neutrons) whereas the ratio $\alpha$ of the real to imaginary part of the forward scattering amplitude $f(0)$ differs from the ratio $\alpha$ in free space indicating a dropping of $Re f(0)$ at finite nuclear density. The extrapolated $K^-$ potential at a momentum of 0.8 GeV/c amounts to $\approx $--28 MeV at density $\rho_0$ which is substantially less than the values extracted from kaonic atoms at zero momentum or heavy-ion data at 300 MeV/c${\leq}p_K{\leq}$600 MeV/c. We, furthermore, investigate the perspectives of scattering experiments on $^{12}C$ at low ($\approx$300 MeV/c) and high ($\approx$1.2 GeV/c) momenta.