Description
As an alternative to Feynman rules, the on-shell formalism provides an efficient and elegant framework for computing amplitudes with an arbitrary number of external particles. While the massless case is well established, much less is known for the massive case. In this talk, I present recursion relations for evaluating n-point massive on-shell amplitudes, thereby filling the gap between the massless and massive frameworks. The method applies to QED, electroweak, and supergravity theories. I will also discuss recent advances in higher-spin amplitudes.