N-jettiness subtractions for g g → 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, $\mathcal{T}$N, subleading power corrections in $\tau=\mathcal{T}$N/Q, with Q a hard interaction scale, can also be systematically computed. We study the structure of power corrections for 0-jettiness, $\mathcal{T}$0, for the gg → H process. Using the soft-collinear effective theory we analytically compute the leading power corrections αsτlnτ and $\alpha_{2s\tau}$ln$\tau$ and $\alpha_{s}^{2}$In$^{3}\tau$ (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 $q\bar{q}$ channels. This includes a numerical extraction of the αsτ and $\alpha_{s\tau}$ and $\alpha_{s}^{2}$In$^{2}\tau$ corrections, and a study of the dependence on the $\mathcal{T}$0 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 $q\bar{q}$ 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