Modern on-shell methods allow to compute scattering amplitudes without
direct reference to the Lagrangian and Feynman rules. In this talk, I
concentrate on tree-level QCD amplitudes involving massive quarks in
four dimensions. I will present all-multiplicity formulae for such
amplitudes and explain how they can be derived using the following two
methods:
1). the on-shell recursion due to Britto, Cachazo, Feng and Witten;
2). the spinor-helicity formalism, recently extended to massive
particles by Arkani-Hamed, Huang and Huang.
I will also discuss their applicability to gravitational scattering
amplitudes and comment on applications to classical gravitational
scattering of spinning black holes.
Zoom link: https://cern.zoom.us/j/95923598030?pwd=N0dTMUJUcHNSaGpCT0g5bU1qT1NLUT09
