HET Journal club: Paolo Benincasa

Speaker: Paolo Benincasa

Title: Scattering amplitudes as differential forms in kinematic space

Abstract: I will lead the discussion on the recent paper arXiv:1711.09102 [hep-th] where a new geometrical picture is proposed for understanding and computing scattering amplitudes. The main idea is to consider amplitudes as differential forms in kinematic space. It is explored for different theories:
i) bi-adjoint ϕ theory (I): this formulation allows to make a direct connection with a polytope (the associahedron) living in kinematic space whose canonical form computes the tree-level amplitudes, and whose combinatorial properties determine properties such as locality, unitarity and soft limits;
ii) bi-adjoint ϕ theory (II): its CHY formulation can be re-derived from this formulation, via interpreting the scattering equations as diffeomorphisms between the associahedron of the moduli-space of the open-string worldsheet and the associahedron of i) in kinematic space;
iii) Yang-Mills theory: it allows to have a color-dressed amplitude without explicit color factor and provide a geometrical insights on the color-kinematics duality.
I will try to go through the most important points of this formulation and of i), ii) and iii).