A Powheg generator for $t$- and $s$-channel single-top production and decay including non-resonant effects

We present a next-to-leading order + parton shower generator for $t$- and $s$-channel single-top production in hadron colliders, for a leptonically-decaying top, including off-shell and non-resonant effects. The generator, publicly available in the POWHEG BOX RES framework, describes the hadro-production of a $b$-jet and a leptonically decaying $W$-boson, accompanied by an additional jet, i.e. $pp\to {\mathrm{\ell }}^{+}{\nu }_{\mathrm{\ell }}{j}_{b}j$ and $pp\to {\mathrm{\ell }}^{-}{\bar{\nu }}_{\mathrm{\ell }}{j}_{\bar{b}}j$, where $j_b$ ($j_{\bar{b}}$) is a jet containing a bottom (anti)quark, and $j$ is a generic jet. We also provide an interface to the Pythia parton shower, suited to matching in the presence of decaying resonances such as the top quark. Our matching is designed to combine the advantages of a five-flavour calculation with the description of bottom quark mass effects in final-state jets. We perform a phenomenological study using fiducial cuts and discuss shower effects.