DGLAP Evolution
∂f(x,Q²)/∂ ln Q² = (αs/2π) · P ⊗ f
EVOLUTION STATE
10 GeV²
Q 3.16 GeV
αs(Q) 0.200
nf 4
PION MOMENTUM FRACTIONS
Valence Sea Gluon
💡
At low Q², valence quarks (u, d̄) carry most of the pion's momentum.
SPLITTING MECHANISMS
q q + g
Pqq
Quark radiates gluon
→ valence shifts left
g q +
Pqg
Gluon creates sea pair
→ sea quarks grow
g g + g
Pgg
Gluon self-splits
→ gluon explodes at small x
q g + q
Pgq
Quark emits hard gluon
→ feeds gluon distribution
CONTROLS
1 GeV²10⁶ GeV²
PDF CURVES
x · d̄v(x) Valence
x · g(x) / 10 Gluon
x · Σsea(x) Sea quarks
FPS 60