Standard Model EFTs via On-Shell Methods
Abstract
We present the Standard Model Effective Field Theories (SMEFT) from purely on-shell arguments. Starting from a few basic assumptions such as Poincar\'e invariance and locality, we classify all the renormalisable and non-renormalisable interactions at the lowest order in the couplings. From these building blocks, we review how locality and unitarity enforce Lie algebra structures to appear in the S-matrix elements together with relations among couplings (and hypercharges). Furthermore, we give a fully on-shell algorithm to compute any higher-point tree-level amplitude (or form factor) in generic EFTs, bypassing BCFW-like recursion relations which are known to be problematic when non-renormalisable interactions are involved. Finally, using known amplitudes techniques we compute the mixing matrix of SMEFT irrelevant interactions up to mass dimension 8, to linear order in the effective interactions.
Cite
@article{arxiv.2108.03669,
title = {Standard Model EFTs via On-Shell Methods},
author = {Manuel Accettulli Huber and Stefano De Angelis},
journal= {arXiv preprint arXiv:2108.03669},
year = {2022}
}
Comments
39 + 14 pages; v3:matched published version, typos corrected