Zoltán Trócsányi (Department of Theoretical Physics, Eötvös Loránd University):

All you wanted to know about the strong coupling

Abstract: The theoretical basis of our understanding of fundamental interactions is provided by quantum field theory (QFT). In QFTs our starting point is the Lagrangian density that usually contains free parameters called couplings. The theory of strong interaction is described by the Lagrangian of quantum chromodynamics (QCD) that contains the masses of the quarks and the strong coupling α_s as free parameters. The latter controls the strength of the strong interactions among coloured particles. Thus, it is a fundamental parameter of nature that influences not only the rates of particle interactions, but also the fate of the universe the most significantly among the fundamental couplings together with the mass of the heaviest quark.

In my talk I will discuss how α_s can be determined and also the status of its measurements and possible further improvements.

About the lecturer:

• Curriculum Vitae