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arXiv · 1903.11023

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

Tobias Neumann·Zack Sullivan
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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.

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Tobias Neumann, Zack Sullivan. 2019-03-26. Off-shell single-top-quark production in the Standard Model Effective Field Theory. https://doi.org/10.1007/jhep06(2019)022

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