Bayes, Ryan David2009-09-292009-09-2920052009-09-29http://hdl.handle.net/1828/1774The search for lepton flavour violation is significant to our understanding of the standard model of particle physics. This measurement uses the muon decay data collected by the TWIST experiment at TRIUMF to search for lepton flavour violation between charged lepton species. Specifically, I searched for the decay µ+→e+X0, where X° is an unknown, undetected, neutral boson, against a background of stan¬dard muon decays, µ+→e+vevµ I set branching ratios for these decays such that B(µ+→e+X0)< 2 x 10-5 - 5 x 10-5, for X0 of various masses accessable by the momenta of the muon decay spectrum, to a confidence level of 95%. This improves upon the previous best limits by a. factor of three. A correction to the spectrum was required to set a limit on a massless X0 of B(µ+→e+X0)< 6.3 x 10-5.enAvailable to the World Wide Webmuonsdecayleptonsnuclear physicsUVic Subject Index::Sciences and Engineering::Physics::AstronomyUVic Subject Index::Sciences and Engineering::Physics::Nuclear physicsThesis