Modern Particle Physics · Problem 6.6

Electron–positron annihilation — Mark Thomson

Physics — Particle Physics

Problem

Using the operator

\hat{S}_n = \frac{1}{2}\mathbf{n} \cdot \boldsymbol{\sigma}

corresponding to the component of spin along an axis defined by the unit vector

\mathbf{n}

at an angle

\theta

to the

z

-axis, express the spin states of the

\mu^+\mu^-

system in terms of the eigenstates of

\hat{S}_z