Coupled-channel effects in the pp -> ppK+K- reaction

TL;DR

This study measures the pp -> ppK+K- reaction cross sections at various energies, revealing the significant role of Kar{K} final state interactions and coupled-channel effects, including charge-exchange processes.

Contribution

It provides the first detailed analysis of coupled-channel effects and final state interactions in the pp -> ppK+K- reaction near threshold energies.

Findings

K+K- spectrum shape reflects strong final state interactions.

Data suggest dominance of isospin-zero production.

Evidence of coupled-channel effects including charge exchange.

Abstract

The cross sections for the pp -> ppK+K- reaction were measured at three beam energies 2.65, 2.70, and 2.83 GeV at the COSY-ANKE facility. The shape of the K+K- spectrum at low invariant masses largely reflects the importance of K\bar{K} final state interactions. It is shown that these data can be understood in terms of an elastic K+K- rescattering plus a contribution coming from the production of a K0\bar{K}0 pair followed by a charge-exchange rescattering. Though the data are not yet sufficient to establish the size of the cusp at the K0\bar{K}0 threshold, the low mass behaviour suggests that isospin-zero production is dominant.