Speaker
Description
A crucial step in the investigation of subleading-power corrections is the process-dependent matching from QCD onto SCET$_{\rm II}$. In this matching, one often first performs the hard matching to SCET$_{\rm I}$ and in a second step matches onto SCET$_{\rm II}$.
However, the matching from SCET$_{\rm I}$ to SCET$_{\rm II}$ is process-independent, and thus lends itself to a systematic investigation. These universal matching relations then provide a basis for numerous applications to next-to-leading power SCET$_{\rm II}$ observables.
In this talk, I provide an overview of the one-loop matching at subleading power in SCET$_{\rm II}$.
To facilitate this matching, it proves useful to consider an effective Lagrangian encompassing both hard-collinear, collinear and soft modes. This Lagrangian can be constructed systematically to all-orders along the same lines as the usual SCET$_{\rm I}$ Lagrangian, but this time with a more involved gauge-symmetry. Additionally, I provide an overview of the novel structures appearing at the one-loop level, and discuss an example matching as a practical application of the Lagrangian.