Non-resonant kaon pair production and medium effects in proton–nucleus collisions

Abstract

We study the non-resonant (non-ϕ) production of KK +− pairs by protons of 2.83 GeV kinetic energy on C, Cu, Ag and Au targets within the collision model, based on the nuclear spectral function, for incoherent primary proton– nucleon and secondary pion–nucleon creation processes. The model takes into account the initial proton and final kaon absorption, target nucleon binding and Fermi motion as well as nuclear mean-field potential effects on these processes. We calculate the antikaon momentum dependences of the exclusive absolute and relative KK +− pair yields in the acceptance window of the ANKE magnetic spectrometer, used in a recent experiment performed at COoler SYnchrotron (COSY), within the different scenarios for the antikaon–nucleus optical potential. We demonstrate that the above observables are strongly sensitive to this potential. Therefore, they can be useful to help determine the K − optical potential from the direct comparison of the results of our calculations with the data from the respective ANKE-at-COSY experiment. We also show that the pion–nucleon production channels dominate in the lowmomentum K − , K + production in the considered kinematics and, hence, they have to be accounted for in the analysis of these data.