Calculation of particle life span

[ribbie]

Is there a relationship between the inverse fine-structure constant (alpha) and the life span of elementary particles?

 

[Bill_K]

Indirectly yes. Decays of the elementary particles such as μ → e + ν_e + ν_μ are governed by the weak interaction. The original description of the weak interactions was in terms of a weak coupling constant G. We now know that the weak and the electromagnetic interactions are two aspects of a single electroweak interaction, and G ~ g²/M_W² where M_W is the mass of the W boson and g is a coupling constant that differs from the fine structure constant only by a small factor: g sin θ_W = e where θ_W is the weak mixing angle.