Speaker
Markus Huber
Description
QCD has a rich spectrum that encompasses bound states of different types, among them glueballs. Pure Yang–Mills theory provides a clean setup to study them, and its spectrum has been established by various methods, including functional equations. This method describes how massless gluons form massive bound states. If quarks are included, the system of equations is enlarged and describes the mixing with conventional mesons which aggravates both experimental searches and theoretical calculations. I discuss the construction of a parameter-free setup that underlies the calculation of (pure) glueballs and the resulting spectrum and describe the steps towards including quarks.