From the Higgs particle to the Big Bang
The characteristics of the smallest subatomic particles and the forces between them determine the properties of all matter and of the universe. Fundamental insights regarding the structure of matter are being obtained using the methods of nuclear and elementary particle physics and combining them with the observations and measurements of astroparticle physics at the intersections of nuclear physics and particle physics, astronomy, astrophysics and cosmology.
What is the goal?
The goal is to find out “what holds the world together?”. This involves the understanding of the characteristics of the smallest particles, the forces between them, the role of symmetries and the validity of the laws of physics under extreme conditions. It includes to understand the structure of matter in atomic nuclei as well as the formation of chemical elements shortly after the Big Bang and in the stars, the formation of supermassive black holes and the acceleration of cosmic particles to energies that are up to one-hundred million times higher than, for example, the man-made LHC. And finally, we want to clarify the role of gravitation, dark matter and the neutrinos; these are all topics that are hardly comprehended yet.
What is Helmholtz doing to achieve this goal?
The program Matter and the Universe was newly formed from its predecessors elementary particle physics, hadrons & nuclei and astroparticle physics. They will be developed together in the future as three program topics T1) Fundamental Particles and Forces, T2) Cosmic Matter in the Laboratory and T3) Matter and Radiation from the Universe. The research program is unique worldwide due to this bundling of expertise and this thematic breadth and width. It is supported by high-performance research infrastructures like accelerator facilities, large-scale detectors, data centers, observatories, and more.
Furthermore, the Helmholtz Association maintains a lively network with German universities and international partners. These strategic partnerships in the research field Matter should be further developed by means of a novel network consisting of programs, alliances and communities (“MUTLink”), to enrich scientific discussions and to raise synergies.
Examples of research
The production and detailed description of heavy elements are a characteristic of the GSI Helmholtz Centre for Heavy Ion Research, whose work-program will be heavily extended due to the large-scale facility FAIR (Facility for Antiproton and Ion Research). The Forschungszentrum Jülich (FZJ) is also involved in these efforts. The FZJ is preparing a novel measurement of the electric dipole moment of protons with the aid of the storage ring COSY. This property could be significant for the obvious complete disappearance of anti-matter from the universe. The interactions between quarks and the validity of further fundamental symmetries between matter and anti-matter are in the focus of the BELLE experiment at the SuperKEKB accelerator in Japan.
The activities at the Large Hadron Collider LHC at CERN in Geneva have achieved a breakthrough that has been desired for four decades; scientists from DESY and numerous university partners have discovered a “Higgs boson” in the experiments ATLAS and CMS that could be responsible for the masses of all other particles. The illustration here shows a computer reconstruction of the decay of a Higgs particle in two gamma quanta (dotted), which then leave behind distinctive signals in the energy detector (light-blue bars). This search requires huge capacities in computing power and data storage. The Tier-1 data processing center GridKa in Karlsruhe, and Tier-2 centers in Hamburg and Darmstadt are major contributions by the Helmholtz Association to the whole Community.
Scientists are intensively searching the LHC data for reactions in which a neutral massive particle escapes unseen from the detectors. In this manner they hope to find particles of Dark Matter, of which there has to be five times as much compared to the corresponding visible matter in the universe. These objects are also being sought for with the aid of sensitive germanium detectors, which are particularly well-shielded against cosmic radiation in the underground laboratory of the Fréjus-Tunnel. The EDELWEISS experiment is another project in which researchers of the Helmholtz Association are involved.
The Karlsruhe Tritium Neutrino Experiment KATRIN is a huge technological challenge. No other experiment worldwide will be capable of constraining in a model-independent way the neutrino mass with the sensitivity of 0.2 electronvolt; this corresponds to 1/250,000 of the mass of an electron. The facility should go into operation mid-2016.