CMB ANGULAR POWER SPECTRUM

Cl vs ℓ · acoustic peaks · Sachs-Wolfe plateau · Silk damping tail
Power Spectrum

Cl = <|a_lm|²>
D_l = l(l+1)Cl/2π

1st peak: ℓ ≈ 220
θ_s ≈ 1°/√(Ω_m)

Peak ratio → Ω_b:
Higher Ω_b → boosts
odd peaks, suppresses
even peaks

Silk damping:
exp(-(ℓ/ℓ_D)²)
ℓ_D ≈ 1500

SW plateau:
Cl ≈ const (ℓ < 30)
from inflation