2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/125667We define the collinear factorization scheme, which absorbs only the collinear physics into the parton distribution functions. In order to isolate the collinear physics, we introduce a procedure to combine real and virtual corrections, canceling infrared singularities prior to integration. In the collinear scheme, the factorization scale $μ$ has a simple physical interpretation as a collinear cutoff. We present a method for choosing the factorization scale and apply it to the Drell-Yan process; we find $μ\approx Q/2$, where $Q$ is the vector-boson invariant mass. We show that, for a wide variety of collision energies and $Q$, the radiative corrections are small in the collinear scheme for this choice of factorization scale.25 pages, 18 figuresHigh Energy Physics - Phenomenologytext