Limits On Production Of Unpaired Electrons Or Positrons In 18-Gev-C Pi+/-P Interactions

Using the Stanford Linear Accelerator Center Hybrid Facility 1-m bubble chamber with tantalum plates, a search was made for single electrons or positrons produced directly in 18-GeV/c ${\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}$ interactions. At 90% confidence level (C.L.), $R=\frac{{e}^{\ifmmode\pm\else\textpm\fi{}}}{{\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}}<2.4\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$. In addition, a limit can be set on charmed particle pair or associated production channels in terms of their semielectronic decay branching ratios, namely, $\ensuremath{\sigma}[{R}_{1}+{R}_{2}]<2.4$ \ensuremath{\mu}b at 90% C.L.