Power Corrections in the N-jettiness Subtraction Scheme
  We discuss the leading-logarithmic power corrections in the $N$-jettiness subtraction scheme for higher-order perturbative QCD calculations. We compute the next-to-leading order power corrections for an arbitrary $N$-jet process, and we explicitly calculate the power correction through next-to-next-to-leading order for color-singlet production for both $q\bar{q}$ and $gg$ initiated processes. Our results are compact and simple to implement numerically. Including the leading power correction in the $N$-jettiness subtraction scheme substantially improves its numerical efficiency. We discuss what features of our techniques extend to processes containing final-state jets. 
Radja Boughezal, Xiaohui Liu and Frank Petriello
hep-ph