An apparatus for the measurement of the transverse polarization of positrons from the decay of polarized muons

Abstract An apparatus for the measurement of the two transverse polarization components P T 1 and P T 2 of the positrons from polarized μ + decay is described. It makes use of a stroboscopic method which cancels many systematic asymmetries and allows one to use muon stop rates in the order of up to 10 8 s −1 . The experiment aims at an accuracy of Δ P T 1 =Δ P T 2 =3×10 −3 and by that at an improvement of the existing limit by nearly one order of magnitude. With these results one will obtain an improved model-independent value for the Fermi coupling constant G F and more stringent limits to possible violations of time reversal invariance in a purely leptonic reaction.