Objectives

The Standard Model of the strong, electromagnetic and weak interactions has
enjoyed many splendid successes in the last decades. Still, it features two
open ends. One is related to the mass generation of its fundamental building
blocks -- the quarks and the leptons -- through the elusive Higgs field presently
investigated at the Large Hadron Collider (LHC). The second one is the
formation and understanding of  the forms of strongly interacting matter
as hadrons and atomic nuclei that  are consistent with the underlying gauge
theory, Quantum Chromodynamics (QCD), and  its symmetries. This nonperturbative regime of the strong interactions is the central topic of this CRC. The following challenges  will be taken up within the CRC:

  • What forms of strongly interacting particles and matter are
    generated by  QCD?
  • How are the underlying symmetries manifested in the spectrum and
    interactions of QCD?

Consequently, the research is grouped into two research areas called
``symmetries'' and ``emergence of structure'', featuring five and eight
research projects, correspondingly. Naturally, these areas
are strongly intertwined and there is a sizeable overlap between the
various subprojects. To make progress on these challenging topics, we will
utilize the most developed theoretical tools based on lattice simulations,
effective field theories and symmetry-constrained modeling. The research
performed within this CRC is unique as we try to establish firm connections
between hadronic and nuclear physics. These two areas are usually considered
separately. This unification is driven in part by the successful application
of the chiral effective Lagrangian of QCD to mesonic, meson-baryon and
baryon-baryon interactions as pioneered by Weinberg. Furthermore, the many
recent puzzling states found at the B-factories and colliders including charm quarks/antiquarks require  a novel look at the structure formation in QCD -- the time-honoured quark model in which essentially all hadron states could be described as quark-antiquark or three quark compounds needs to be extended and revised. This research is intimately connected to the plethora of data from the
BESIII experiment at the Beijing-Electron-Positron-Collider II as well as
from other operating facilities world-wide and, in the future, from the
antiproton experiments  with PANDA at the FAIR facility.
In addition, precision calculations in hadron and nuclear physics combined with accurate measurements allow for fine tests of physics beyond the Standard Model. This  defines the precision frontier that nicely complements the high energy
frontier that is investigated at the LHC. Such type of investigations will
also be performed within this CRC.