HET- seminar: Karol Kampf

Speaker:  Karol Kampf

Title: Amplitudes methods for effective field theories

Abstract:  Description of low-energy interactions of Goldstone particles of
spontaneously broken symmetries is traditionally done using the most
general action based on the underlying symmetry. All such possible terms
are taken up to a given order in the low energy expansion. The
explicitly constructed Lagrangian can be then used for calculating given
scattering amplitudes. However this process is not very efficient as can
be demonstrated already at the tree-level for relatively small number of
external particles. The modern amplitude methods offer different
approach where it is possible to avoid redundancy stemming from the
standard Feynman diagram calculations. The methods represent not only an
efficient way of calculating scattering amplitudes but can be employed
in theoretical studies of their interesting properties. This allowed
among other things to classify the effective models. In this talks
mainly spin-0 and spin-1 EFTs will be discussed.