Search for the H-dibaryon resonance in {sup 12}C (K{sup -},K{sup +}{lambda}{lambda}X)

The H-dibaryon resonance was sought by a {lambda}{lambda} invariant mass spectrum that was obtained by the {sup 12}C (K{sup -},K{sup +}{lambda}{lambda}X) reactions. We observed a bump near the {lambda}{lambda} threshold, as reported by the previous experiment (KEK E224), with better statistics. Data were compared with results of a cascade model calculation including {lambda}{lambda} final state interactions consistent with the newly measured binding energy of {sub {lambda}}{sub {lambda}}{sup 6}He. No significant enhancements above levels of the model predictions were observed. The resulting upper limit for the production cross section of the H with a mass range between the {lambda}{lambda} and {xi}N threshold is found to be 2.1 {+-} 0.6 (stat.) {+-} 0.1 (syst.) {mu}b/sr at a 90% confidence level.