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arXiv · 2005.13027

Hidden Conformal Invariance of Scalar Effective Field Theories

Clifford Cheung·James Mangan·Chia-Hsien Shen
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Abstract

We argue that conformal invariance is a common thread linking several scalar effective field theories that appear in the double copy and scattering equations. For a derivatively coupled scalar with a quartic ${\cal O}(p^4)$ vertex, classical conformal invariance dictates an infinite tower of additional interactions that coincide exactly with Dirac-Born-Infeld theory analytically continued to spacetime dimension $D=0$. For the case of a quartic ${\cal O}(p^6)$ vertex, classical conformal invariance constrains the theory to be the special Galileon in $D=-2$ dimensions. We also verify the conformal invariance of these theories by showing that their amplitudes are uniquely fixed by the conformal Ward identities. In these theories, conformal invariance is a much more stringent constraint than scale invariance.

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Clifford Cheung, James Mangan, Chia-Hsien Shen. 2020-05-26. Hidden Conformal Invariance of Scalar Effective Field Theories. https://doi.org/10.1103/physrevd.102.125009

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