Automated Computation of One-Loop Amplitudes

rhe automation of one-loop amplitudes plays a key role in address) several computational challenges for hadron collider phenomenology: They are needed for simulations including next-to-leading-order corrections, which can be large at hadron colliders. They also allow the exact computation of loop-induced processes. A high degree of automation has now been achieved in public codes that do not require expert knowledge and can he widely used in the high-energy physics conununity. In this article, we review many of the methods and tools used for the different steps of automated one-loop amplitude calculations: renormalization of the I,agrangian, derivation and evaluation of the. amplitude, its decomposition onto a basis ofscalar integrals and their subsequent evaluation, as well as computation of rational terms.