Scattering amplitudes from generalized recursion[HBNI Th214]

Abstract

In last few decades, the S-matrix program of quantum field theory has witnessed a number of remarkable developments: a) the study of analytic structure of S-matrix has revealed strikingly new insights in our understanding of quantum field theory, b) on-shell techniques like Britto-Cachazo-Feng-Witten (BCFW) recursion relations and gen- eralised unitarity have enormously reduced the complexity of seemingly impossible computations which guided the next to leading order (NLO) revolution in Quantum Chro- modynamics (QCD) and have even been used to calculate classical observables such as potential that models the merger of binary black-holes up to high order in post Newtonian and post Minkowskian expansion. This thesis is devoted to the derivation of a new on-shell recursion scheme for computing scattering amplitudes in gauge theories in four spacetime dimensions, involving massive particles. The recursion relations are then used to calculate particular classes of amplitudes involving massive vector bosons in Higgsed Yang-Mills theories.