Search for baryon-number and lepton-number violating decays of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi mathvariant="bold">Λ</mml:mi></mml:math>hyperons using the CLAS detector at Jefferson Laboratory

Abstract

We present a search for ten baryon number violating decay modes of $\mathrm{\ensuremath{\Lambda}}$ hyperons using the CLAS detector at Jefferson Laboratory. Nine of these decay modes result in a single meson and single lepton in the final state ($\mathrm{\ensuremath{\Lambda}}\ensuremath{\rightarrow}m\ensuremath{\ell}$) and conserve either the sum or the difference of baryon and lepton number ($B\ifmmode\pm\else\textpm\fi{}L$). The tenth decay mode ($\mathrm{\ensuremath{\Lambda}}\ensuremath{\rightarrow}\overline{p}{\ensuremath{\pi}}^{+}$) represents a difference in baryon number of two units and no difference in lepton number. We observe no significant signal and set upper limits on the branching fractions of these reactions in the range $(4--200)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}7}$ at the 90% confidence level.