Speaker
Mr.
Jorge León Silverio
(BUAP)
Description
Modern methods for computing scattering amplitudes are based on the concept of Wigner's little group, which characterizes the quantum states of particles. At tree level, helicity spinors are used for massless particles, while spin-spinors are used for massive ones. In this talk, we review Wigner's little group, helicity spinors and spin-spinor variables. We present the quantum states of the decay of a W boson into a lepton and an antineutrino, electron positron annihilation. We discuss the massless limit of a massive theory and its discontinuities.
