Subthreshold and near threshold K+ meson production on light nuclei by protons
Institute for Nuclear Research, Russian Academy of Sciences, 117312 Moscow, Russia
Received: 26 October 1998 / Revised version: 10 February 1999 Communicated by W. Weise
The inclusive K+ meson production in proton-nucleus collisions in the near threshold and subthreshold energy regimes is analyzed with respect to the one-step (, ) and two-step () incoherent production processes on the basis of an appropriate folding model, which takes properly into account the struck target nucleon removal energy and momentum distribution (nucleon spectral function), novel elementary cross sections for proton-nucleon reaction channel close to threshold as well as nuclear mean-field potential effects on the one-step and two-step kaon creation processes. A detailed comparison of the model calculations of the K+ total and differential cross sections for the reactions p+Be9 and p+C12 with the existing experimental data is given, illustrating both the relative role of the primary and secondary production channels at considered incident energies and those features of the cross sections which are sensitive to the high momentum and high removal energy part of the nucleon spectral function. It is found that, contrary to previous studies performed in the literature, the pion-nucleon production channels do not necessarily dominate in pA collisions at subthreshold energies and the relative strength of the proton and pion induced reaction channels in light target nuclei in the subthreshold energy regime is governed by the kinematics of experiment under consideration.