Search for right-handed currents in muon decay

Limits are reported on right-handed currents, based on precise measurement of the e+ spectrum end point in μ+ decay. Highly polarized muons from the TRIUMF surface beam were stopped in metal foils within a 1.1 T spin-holding longitudinal field or a 70 G spin-processing field. For the spin-held data, the V-A rate vanishes in the beam direction at the end point. Measurement of this rate sets the 90% confidence limits xiP/sub μ/delta/rho > 0.9959 and M(W/sub R/) > 380 GeV, where W/sub R/ is the possible right-handed gauge boson. The μSR signal amplitude of the spin-precessed data independently sets the limits xiP/sub μ/delta/rho > 0.9918 and M(W/sub R/) > 320 GeV. Limits on non-(V-A) currents, familons, and composite leptons are also presented