Starting week 15, 2025 – every Thursday from 2pm - 4pm in room B1 – ending week 22, 2025 Week 17 = Easter holiday

Description of the course:

Analyticity, unitarity and crossing symmetry are general properties of the S-matrix as well as of matrix elements of operators in any quantum field theory. For specific quantities these properties can be cast into the form of dispersion relations. These are satisfied in both the perturbative as well as the non-perturbative regime and are useful in different ways in the two cases. After introducing the basics of dispersion relations, the course will focus on their application to strong interactions at low energy. We will start by considering two-point functions of operators, then form factors, and finally $2 \to 2$ scattering amplitudes, as well as four-point functions. Dispersion relations are one of the main tools to tackle strong interactions at low energy and are complementary to lattice QCD and Chiral Perturbation Theory.

Learning results of the course:

In the course I will also discuss how these complementarities can be used to reach a better understanding of the physics of strong interactions in this regime.

Lecturer:

Prof. Gilberto Colangelo