Rare t decays

A compilation of experimental limits on some rare t decays is shown in Table 14.2 (from Heusch, 1989). Such decays could best be pursued at a T factory. Such facilities have already been advocated. 

One suggestion is to have colliding high luminosity e e beams with energy in the range 3.0-4.2 GeV with the aim of producing up to 10 r lej)-tons per year. This would involve production of about 10 J/ and 10 charm mesons per year. The design luminosity is 10 cm /s. 

It should be noted that the heavy mass of the r (and, therefore, its ability to decay weakly into ordinary hadrons) makes it a unique probe of the coupling to the standard quarks and leptons of any new weak boson. Also, the T may represent one of the dominant and more tractable decay modes of charged Higgs bosons. 

It should, finally, be mentioned that excited r leptons which would manifest themselves through e e — r +r — t t 77 or e e T T r T 7 have been excluded by LEP searches up to masses as high as 45 GeV/c (see, for instance, L3, 1990c). 

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