Holographic Quantum Chromodynamics and Hadron Physics

Hadrons are elementary particles that are subject to the strong nuclear forces, whose fundamental theory is provided by quantum chromodynamics (QCD). Several aspects of QCD are prohibitively difficult to approach with standard methods. Holographic QCD (hQCD) is a new approach, based on a duality between strongly coupled gauge theories in 4 dimensions and gravitational theories in 5 dimensions. This project aims at developing hQCD beyond its current limitations with applications to hadron physics including hadronic light-by-light scattering, central exclusive production of mesons and glueballs at high-energy colliders, as well as the phase structure of dense baryonic matter in neutron stars.

Hadrons are elementary particles that are subject to the strong nuclear forces, whose fundamental theory is provided by quantum chromodynamics (QCD). Several aspects of QCD are prohibitively difficult to approach with standard methods. Holographic QCD (hQCD) is a new approach, based on a duality between strongly coupled gauge theories in 4 dimensions and gravitational theories in 5 dimensions. This project aimed at developing hQCD beyond its current limitations with applications to hadron physics including hadronic light-by-light scattering, central exclusive production of mesons and glueballs at high-energy colliders, as well as the phase structure of dense baryonic matter in neutron stars. With the results obtained, it becomes possible to improve the theoretical prediction for the anomalous magnetic moment of muons, which is currently measured in an experiment at Fermilab near Chicago at an accuracy of 11 significant digits. For glueballs - elementary particles that result purely from the self-interactions of the strong nuclear force - characteristic decay patterns involving also photons could be determined. And for the dense matter in the core of neutron stars it was possible to derive a model providing an explanation for the expected ultrarelativistic speed of sound, which was also used to evaluate the patterns of gravitational waves resulting from mergers of neutron stars.