Search for superdense nuclei of Rb and Cs among the products of 8 GeV proton interactions with Ta

Experimental searches for β-active superdense nuclei of Rb and Cs among the products of 8 GeV proton interactions with Ta are described. The method of selective off-line mass-separation with scanning of the β-activity distribution on the collector was used. According to π-condensation theory, the long-lived anomalous nuclei are expected to be more neutron-deficient than the usual ones. Moreover, their mass numbers may be significantly nonintegral measured on the normal mass scale, because of unusual binding energy. These predictions guided the present search. No anomalous nuclei were found. The upper limit for Rb nuclei in the range 69 <= A <= 78 is 10-5 with respect to yield for 81Rb; for Cs in the range 112 <= A <= 122 the limit is (5-10) x 10-6 of the yield for 127Cs. These estimations are based on the assumption that the half-life of superdense nuclei equals 5 h. (orig.)