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 qq¯ 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.