Seminars IFIC

Scattering Amplitudes in Gauge Theories: from tree- to multi-loop-level calculations

by William J. Torres Bobadilla (IFIC CSIC-UV)

Wednesday, 26 April 2017 from to (Europe/Brussels)
at Universe ( 1001-Primera-1-1-1 - Paterna. Seminario )
In this talk I review modern techniques for analytic calculation of scattering amplitudes. At tree level, with the knowledge of the S-matrix and formal properties of gauge invariant objects, I discuss the advantage of reformulating traditional methods based on the Lagrangian. For multi-loop-level, I concentrate on integrand reduction methods, which allow for a decomposition of the scattering amplitude into multi-particle poles. Non-trivial examples are presented for the calculation of one- and two-loop scattering amplitudes. For the former I use a new regularisation scheme, Four-dimensional Formulation (FDF), which particles propagating inside the loop are represented by four-dimensional massive internal states regulating the divergencies. The conventional dimensional reduction (CDR) is used for the later.
Organised by LHCPHENO