Subthreshold and near-threshold kaon and antikaon production in proton–nucleus reactions

The differential production cross sections of K+ and K− mesons have been measured at the ITEP proton synchrotron in p + Be, p + Cu collisions under a laboratory angle of 10.5°, respectively, at 1.7 and 2.25, 2.4 GeV beam energies. A detailed comparison of these data with the results of calculations within an appropriate folding model for incoherent primary proton–nucleon, secondary pion–nucleon kaon and antikaon production processes and processes associated with the creation of antikaons via the decay of intermediate mesons is given. We show that the strangeness exchange process YN → NNK− gives a small contribution to the antikaon yield in the kinematics of the performed experiment. We argue that in the case when antikaon production processes are dominated by the channels with KK− in the final state, the cross sections of the corresponding reactions are weakly influenced by the in-medium kaon and antikaon mean fields.