Loops and trees in generic EFTs

Craig, N., Jiang, M., Li, Y.-Y. and Sutherland, D. (2020) Loops and trees in generic EFTs. Journal of High Energy Physics, 2020, 86. (doi: 10.1007/JHEP08(2020)086)

Abstract

We consider aspects of tree and one-loop behavior in a generic 4d EFT of massless scalars, fermions, and vectors, with a particular eye to the high-energy limit of the Standard Model EFT at operator dimensions 6 and 8. First, we classify the possible Lorentz structures of operators and the subset of these that can arise at tree-level in a weakly coupled UV completion, extending the tree/loop classification through dimension 8 using functional methods. Second, we investigate how operators contribute to tree and one-loop helicity amplitudes, exploring the impact of non-renormalization theorems through dimension 8. We further observe that many dimension 6 contributions to helicity amplitudes, including rational parts, vanish exactly at one-loop level. This suggests the impact of helicity selection rules extends beyond one loop in non-supersymmetric EFTs.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Sutherland, Dr David
• Authors: Craig, N., Jiang, M., Li, Y.-Y., and Sutherland, D.
• College/School: College of Science and Engineering > School of Physics and Astronomy
• Journal Name: Journal of High Energy Physics
• Publisher: Springer
• ISSN: 1126-6708
• ISSN (Online): 1029-8479
• Copyright Holders: Copyright © 2020 The Authors
• First Published: First published in Journal of High Energy Physics 2020:86
• Publisher Policy: Reproduced under a Creative Commons licence