We compare recent, seemingly different, approaches to transverse momentum dependent factorization (due to Echevarria, Idilbi, and Scimemi and to Collins), and show that they are the same, apart from an apparent difference in their definition of the $\overline{\mathrm{MS}}$ renormalization scheme.

• Received 28 November 2012

DOI:https://doi.org/10.1103/PhysRevD.87.034018