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

TL;DR

This study models non-resonant kaon pair production in proton-nucleus collisions, showing that observables are highly sensitive to the antikaon-nucleus optical potential, aiding its experimental determination.

Contribution

It introduces a comprehensive collision model including nuclear medium effects to analyze kaon pair production and sensitivity to the antikaon optical potential.

Findings

Observables are highly sensitive to the K- optical potential.

Pion-nucleon channels dominate low-momentum kaon production.

Model aligns with recent COSY experiment data.

Abstract

We study the non-resonant (non-$\phi$) production of $K^+K^-$ 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 $K^+K^-$ pair yields in the acceptance window of the ANKE magnetic spectrometer, used in a recent experiment performed at 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 low-momentum $K^-$, $K^+$ production in the considered kinematics and, hence, they have to be accounted for in the analysis of these data.