Resummation for direct photon and W + jet production
Nikolaos Kidonakis
TL;DR
This work tackles large logarithmic corrections from soft-gluon emission in threshold regions for direct photon and $W$+jet production. It employs a $N$-space (Mellin-space) factorization into $\psi$, $J$, $S$, and $H$ with a soft anomalous dimension $\Gamma_S$, enabling NNLO expansions of the resummed cross sections. Explicit NNLO soft-gluon contributions are derived for key channels $qg \rightarrow q\gamma$ and $q\bar{q} \rightarrow gW$, including plus-distribution structures and matching to exact NLO results. The resulting predictions show reduced scale dependence and improved precision near threshold, with implications for gluon-distribution determinations and backgrounds to new physics.
Abstract
I discuss the resummation of soft gluon contributions to direct photon and W + jet production and I present some results for the next-to-next-to-leading order expansions of the resummed cross sections for these processes near threshold.