Amplitude analysis of the K-K+ system produced in the reactions π-p→K-K+n and π+n→K-K+p at 6 GeV/c

We have carried out an amplitude analysis of the K-K+ system produced in the reactions π-p→K-K+n and π+n→K-K+p using data from a high-statistics experiment performed with the Argonne effective-mass spectrometer. Combining the results from the two reactions allows us to analyze the K-barK production amplitudes in terms of their isospin-zero and -one components. We use phenomenological arguments based on t dependence and on the expected properties of the P and D waves to resolve ambiguities. Our favored solution exhibits an enhancement around 1300 MeV in the isospin-zero S wave produced by π exchange. In this solution the Argand plot for the ππ→K-barK S wave changes rapidly above 1300 MeV, consistent with a resonance at 1425 +- 15 MeV with width 160 +- 30 MeV. We show that our solution is consistent with the features of neutral and charged K-barK systems found in other experiments