Standard Model and Beyond · Problem 7.5

The Standard Electroweak Theory

Physics — Particle Physics · polarized-muon-decay-angular-momentum

Problem

The formula (7.53) for polarized

\mu^-

decay implies that the angular distribution is

1 - \cos\theta

for a massless

e^-

of the maximum allowed energy

m_\mu/2

, where

\theta

is the angle between the

e^-

direction and the muon spin. The analogous formula for

\mu^+

decay is

1 + \cos\theta

. Interpret these results in terms of angular momentum conservation.