Abstract:
In this thesis we studied the muon decay μ → eνeνμ according to the
standard model (SM). We computed the decay width μ and lifetime τμ for
leptonic muon , We found their values μ = 1
2.19×10−6 Second−1 and τμ =
2.19×10−6 second respectively, these results showed a good agreement with the
experimental results. We Used the obtained value of τμ with the given muon
mass to determine the Fermi coupling of weak interaction Gf . In addition,
We have calculated the value of g2, this is the weak coupling constant in the
standard model, we found that: α2 = 1
29 which is larger than the fine structure
constant of the electromagnetic interaction, that is: α1 = 1
137 . Consequently,
the weak interaction is actually found to be not ”weak”, as the word ”weak”
reflect meaning.
