N -jettiness subtractions for gg →h at subleading power

Abstract

N-jettiness subtractions provide a general approach for performing fully-differential next-to-next-to-leading order (NNLO) calculations. Since they are based on the physical resolution variable N-jettiness, TN, subleading power corrections in τ=TN/Q, with Q a hard interaction scale, can also be systematically computed. We study the structure of power corrections for 0-jettiness, T0, for the gg→H process. Using the soft-collinear effective theory we analytically compute the leading power corrections αsτlnτ and αs2τln3τ (finding partial agreement with a previous result in the literature), and perform a detailed numerical study of the power corrections in the gg, gq, and qq̄ channels. This includes a numerical extraction of the αsτ and αs2τln2τ corrections, and a study of the dependence on the T0 definition. Including such power suppressed logarithms significantly reduces the size of missing power corrections, and hence improves the numerical efficiency of the subtraction method. Having a more detailed understanding of the power corrections for both qq̄ and gg initiated processes also provides insight into their universality, and hence their behavior in more complicated processes where they have not yet been analytically calculated.