Triangle Seminars
Wednesday, 18 Apr 2018
Feynman Integrals: symmetries and seagulls
Ruth Shir
(Hebrew University of Jerusalem)
Abstract:
Feynman diagrams will be looked at from a new point of view. 'Symmetries of Feynman Integrals' is an analytical method for calculating Feynman diagrams. It is based on exposing an underlying group structure of a given diagram which defines a set of partial differential equations in the parameter space of the diagram. Group orbits in the diagram’s parameter space are used to reduce the Feynman integral into a line integral. The vacuum seagull, a three-loop diagram, and the propagator seagull, a propagator-type diagram with two loops, will be used to demonstrate the method, and to obtain new results.
Feynman diagrams will be looked at from a new point of view. 'Symmetries of Feynman Integrals' is an analytical method for calculating Feynman diagrams. It is based on exposing an underlying group structure of a given diagram which defines a set of partial differential equations in the parameter space of the diagram. Group orbits in the diagram’s parameter space are used to reduce the Feynman integral into a line integral. The vacuum seagull, a three-loop diagram, and the propagator seagull, a propagator-type diagram with two loops, will be used to demonstrate the method, and to obtain new results.
Posted by: QMW
Thursday, 19 Apr 2018
Cluster algebras, integrability and scattering amplitudes
Georgios Papathanasiou
(DESY)
Abstract:
I present recent progress towards determining the planar S-matrix of maximally supersymmetric Yang-Mills theory, thanks to the rich interplay between its perturbative analytic properties in general kinematics, and its integrable structure in special kinematics. The former are related to cluster algebras, and allow for the computation of amplitudes with six/seven gluons up to six/four loops, whereas the latter yields all amplitudes in the multi-Regge limit at finite coupling.
I present recent progress towards determining the planar S-matrix of maximally supersymmetric Yang-Mills theory, thanks to the rich interplay between its perturbative analytic properties in general kinematics, and its integrable structure in special kinematics. The former are related to cluster algebras, and allow for the computation of amplitudes with six/seven gluons up to six/four loops, whereas the latter yields all amplitudes in the multi-Regge limit at finite coupling.
Posted by: QMW