Experimental data on K+ meson and proton sideward now measured with the FOP
I detector at SIS/GSI in the reactions Ru + Ru at 1.69 A GeV and Ni + Ni at
1.93 A GeV are presented. The K+ sideward flow is found to be anti-correla
ted (correlated) with the one of protons at low (high) transverse momenta.
When compared to the predictions of a transport model, the data favour the
existence of an in-medium repulsive K+-nucleon potential. (C) 2000 Elsevier
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