Off-shell single-top-quark production in the Standard Model Effective Field Theory

Abstract

We present a fully differential and spin-dependent $t$-channel single-top-quark calculation at next-to-leading order (NLO) in QCD including off-shell effects by using the complex mass scheme in the Standard Model (SM) and in the Standard Model Effective Field Theory (SMEFT). We include all relevant SMEFT operators at $1/{\Lambda }^2$ that contribute at NLO in QCD for a fully consistent comparison to the SM at NLO. In addition, we include chirality flipping operators that do not interfere with the SM amplitude and contribute only at $1/{\Lambda }^4$ with a massless $b$-quark. Such higher order effects are usually captured by considering anomalous right-handed $Wtb$ and left-handed $Wtb$ tensor couplings. Despite their formal suppression in the SMEFT, they describe an important class of models for new physics. Our calculation and analysis framework is publicly available in MCFM.

39 pages, 27 figures; v2: match published version

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Cited by in corpus (1)

• Single-top-quark production in the $t$-channel at NNLO