Unimodular gravity (UG) is an alternative to general relativity (GR) which, however, is so
closely related to the latter that one can wonder to what extent they are different. The …

We derive scalar effective field theories—Lagrangians, symmetries, and all—from on-shell
scattering amplitudes constructed purely from Lorentz invariance, factorization, a fixed …

A bstract We systematically explore the space of scalar effective field theories (EFTs)
consistent with a Lorentz invariant and local S-matrix. To do so we define an EFT …

These lectures are a brief introduction to scattering amplitudes. We begin with a review of
basic kinematical concepts like the spinor helicity formalism, followed by a tutorial on …

A bstract We derive new amplitudes relations revealing a hidden unity among a wideranging
variety of theories in arbitrary spacetime dimensions. Our results rely on a set of Lorentz …

A bstract We present the Standard Model Effective Field Theories (SMEFT) from purely on-
shell arguments. Starting from few basics assumptions such as Poincaré invariance and …

We derive the first ever on-shell recursion relations applicable to effective field theories.
Based solely on factorization and the soft behavior of amplitudes, these recursion relations …

A bstract We apply on-shell methods to the bottom-up construction of electroweak
amplitudes, allowing for both renormalizable and non-renormalizable interactions. We use …

A bstract The soft bootstrap is an on-shell method to constrain the landscape of effective field
theories (EFTs) of massless particles via the consistency of the low-energy S-matrix. Given …

This report is centred around tree-level scattering amplitudes in pure Yang–Mills theories,
the most prominent example is given by the tree-level gluon amplitudes of QCD. I will …