Consider the decay 0 in the CM. Assume a Cartesian coordinate system x * , y * , z * >, and

Consider the decay π⁰→γ_γ in the CM. Assume a Cartesian coordinate system x^*, y^*, z^* >, and the polar coordinates ρ^*, θ^*, ϕ^*. In this reference frame, the decay is isotropic. Give the expression of the probability per unit solid angle, P(cosθ^*, ϕ^*)=dN/dΩ^* of observing a photon in the direction θ^*, ϕ^*. Then consider the L reference frame, in which the π⁰ travels in the direction z = z^* with momentum p and write the probability per unit solid angle, P(cosθ, ϕ) of observing a photon in the direction θ, ϕ .