  A consistent factorization theorem is presented in the framework of effective
field theories. Conventional factorization suffers from infrared divergences in
the soft and collinear parts. We present a factorization theorem in which the
infrared divergences appear only in the parton distribution functions by
carefully reorganizing collinear and soft parts. The central idea is extracting
the soft contributions from the collinear part to avoid double counting.
Combining it with the original soft part, an infrared-finite kernel is
obtained. This factorization procedure can be applied to various high-energy
scattering processes.
