Collinear divergences and factorization in perturbative QCD

The issue of choosing a factorization scale in perturbative QCD is examined in detail. First a previously defined factorization scheme called the collinear scheme is implemented on Higgs production by bottom quark fusion, and then extended to Higgs production by gluon fusion. After this the issue of gauge invariance in this collinear scheme is addressed and it is realized that the collinear scheme fails to be gauge invariant. A more general analysis of collinear divergences and the phase space integrated over to calculate cross sections is performed and a new scheme called the generalized collinear scheme is presented for factorization of radiated gluons. Virtual corrections are considered and a possible method of dealing with them is suggested. This generalized collinear scheme is then tested on three 2 → 1 processes with encouraging results.