Equation Icon  (2ℓ)! zℓ [ (ℓ − 2)(ℓ + 2) 𝜖 ] ξℓ(𝜖 ≪ z ≪ 1) = ----------------ℓ+1 1 + i𝜖(aℓ + ln z) − ----------------+ 𝒪 (𝜖2) , (80 ) (ℓ − 2)!(ℓ + 2)!𝜖 2ℓ z