Study of the reactionπ−p→nKS0KS0at 6.0 and 7.0 GeV/c

Abstract

The $K_S^0{K}_S^0$ system produced in the reaction ${\pi }^{-}p\to n{K}_S^0{K}_S^0$ at 6.0 and 7 0 GeV/c has been studied utilizing the ANL 1.5-m streamer-chamber facility. A 400 000-photograph exposure yielded 5096 unweighted $n{K}_S^0{K}_S^0$ events. The cross section for this reaction was determined to be 9.6 ± 1.3 μb at 6.0 GeV/c and 8.7 ± 1.1 μb at 7.0 GeV/c. The decay angular distributions were parametrized in terms of moments of the spherical harmonics. The $〈Y_4^0〉$ moment was fitted to interfering Breit-Wigner amplitudes for the $f$ and $f^{\prime }$ mesons. Using this fit, the branching ratio $R=\frac{\Gamma (f\to K\overline{K})}{\Gamma (f\to \mathrm{all})}$ was found to be (2.3 ± 0.8)%. An energy-independent production-amplitude analysis revealed an enhancement in the $S$-wave amplitude near 1300 MeV. The properties of the $S$-wave enhancement are discussed and compared with those observed in other recent experiments. Extrapolated cross sections for the reaction $\pi \pi \to K_S^0{K}_S^0$ are presented. We find a cross section considerably below the $S$-wave unitarity limit in the $S^{*}$ region.