NNLO $t$-channel single-top-quark production revisited

Single-top-quark production is an important channel for measuring the top-quark mass, the Cabibbo-Kobayashi-Maskawa matrix element $V_{tb}$, and provides strong constraints on the parton distribution functions. Previous NNLO QCD calculations of $t$-channel production disagree by 100\% of the size of the NNLO correction, and are limited to using to top-quark mass as a fixed choice of scale. We present a new fully differential NNLO calculation that allows for a variety of scale choices and tracks $b$-flavored jets.