Experiments to search for superdense nuclei of Cs and Fr among the products of interaction of deuterons (4. 3 GeV) and /sup 3/He (11--15 GeV) with Th

We describe an experimental search for ..beta..-active superdense nuclei of Cs and Fr among the products of interaction of /sup 2/H (4.3 GeV) and /sup 3/He (11--15 GeV) with Th. The search was made by the method of selective mass spectroscopy with scanning of the distribution of beta activity on the collector. According to Migdal's theory of pion condensation it is expected that the track of ..beta.. stability of superdense nuclei is shifted in the direction of N = Z. Therefore as a signal of anomalous properties we chose the appearance of relatively long-lived ..beta..-active isotopes in the region of significant neutron deficit. The following upper limits were obtained for the cross sections for production of anomalous isotopes in units of the total cross section for the interaction (on the assumption T/sub 1//sub ///sub 2/ = 5 hours): for Cs in the interval 112< or =A< or =119--5x10/sup -9/ in the case of a deuteron beam and 2x10/sup -7/ in the interval 100< or =A< or =122 for an /sup 3/He beam; for Fr: 1.6x10/sup -8/ in the interval 163< or =A< or =206 (deuterons) and 2x10/sup -6/ for 172 < or =A< or =210 for the /sup 3/He beam.