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arXiv · 1907.00997

Top quark decay at next-to-leading order in the Standard Model Effective Field Theory

Radja Boughezal·Chien-Yi Chen·Frank Petriello·Daniel Wiegand
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Abstract

We consider top quark decay in the Standard Model Effective Field Theory (SMEFT). We present a calculation of the total decay width and the $W$-boson helicity fractions at next-to-leading order (NLO) in SMEFT. Our result includes the complete set of contributing four-fermion operators in addition to QCD dipole operators and bottom-mass suppressed effects. We show that operators that first appear at NLO in the SMEFT can be bounded by the current data as well as future data from both a high-luminosity LHC and a potential $e^+e^-$ collider, demonstrating the importance of going beyond leading order when studying the SMEFT. We discuss technical aspects of our calculation that we believe will be useful in future higher-order studies of the SMEFT, in particular the treatment of $γ_5$ in loop diagrams.

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Radja Boughezal, Chien-Yi Chen, Frank Petriello, Daniel Wiegand. 2019-12-19. Top quark decay at next-to-leading order in the Standard Model Effective Field Theory. https://doi.org/10.1103/physrevd.100.056023

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