What is an LHC

Large Hadron Collider (LHC) at CERN

With a circumference of 27 kilometers, the Large Hadron Collider LHC is the largest and most powerful particle accelerator that has ever been built. Its ring-shaped tunnel lies a hundred meters below the border area between Switzerland and France. This gigantic large-scale device, which is also known as the "world machine", is operated by the European Organization for Nuclear Research CERN near Geneva.

At the Large Hadron Collider (LHC), protons or lead ions are accelerated to almost the speed of light in order to make them collide at extremely high energies. In the collisions, new tiny particles are created that leave traces in the connected detectors. By evaluating these traces, scientists can gain new knowledge about the smallest building blocks of matter - the elementary particles - and the laws they follow.

With almost double the collision energy

But even a world machine needs maintenance from time to time. The LHC was shut down at the beginning of 2013 after three years for repair work and technical extensions. The CERN technicians used this time out to optimize the measuring instruments and accelerator components at the LHC and to prepare them for higher energies and data rates. The LHC resumed its work in May 2015 - it causes the protons to collide with an energy almost twice as high as before. In the second run time, the particle accelerator creates 13 and later even 14 teraelectron volts. In addition, more particles can collide per time and area. This increases the number of collisions that can be evaluated in the experiments - even more data that should decipher the riddles of physics.

The limits of particle physics

In the 1960s, a theory was developed that describes all known elementary particles and the basic forces acting between them: the standard model of particle physics. Since then, many of his predictions have been confirmed in experiments. However, there are open questions and phenomena that the Standard Model cannot explain.

The Higgs particle was discovered in 2012 with the help of the LHC. It is through interaction with the Higgs particle that other elementary particles acquire their mass in the first place. For the theory of the Higgs particle, Peter Higgs and François Englert received the 2013 Nobel Prize in Physics.

For a long time it was not clear where the particles actually got their mass from. Some scientists hypothesized a special field that permeates our entire universe and is said to be linked to a new type of particle, the Higgs particle. In fact, the discovery of this particle was announced at the LHC in July 2012 - a milestone in particle physics. The fathers of the prediction of this particle, Peter Higgs and François Englert, were subsequently awarded the 2013 Nobel Prize in Physics. In the next step, the LHC researchers want to examine the properties of the Higgs particle in more detail.

What is our universe made of?

The universe around us is also a mystery. As far as we know today, around 27 percent of the universe consists of a substance that is subject to the force of gravity, but is otherwise invisible for all measurements. It is called "dark matter". Another 68 percent of the universe is so-called dark energy - according to astronomical observations it must exist, but its nature is unknown. With the standard model of particle physics, only about 5 percent of the universe can be described! Physicists are also wondering where the antimatter has gone, which must have been created in the same part as matter during the Big Bang. According to current knowledge, every particle has an antiparticle that has exactly the same properties except for its charge. In today's universe, however, the antimatter has almost disappeared.

The experiments at the LHC could provide clues for solving these and other key questions in physics, including exotic particles and new spatial dimensions. The LHC is even able to produce a state of matter that prevailed a millionth of a second after the Big Bang: a hot quantum pulp in which the otherwise bound components of protons, neutrons and other particles buzz around as so-called "quark-gluon plasma". This state is created at the LHC by collisions of lead ions that are almost light-fast.

The CERN (C.onseil E.uropéen pour la R.echerche Nucléaire) was founded in 1954 and was one of the first large-scale European projects. Today a total of 22 member states contribute to the financing of the research center. Germany takes on around 20 percent of the CERN budget with 220 million euros per year, followed by France and Great Britain with 15 and 14 percent respectively. In addition, the Federal Ministry of Education and Research supports projects of so-called collaborative research at the LHC and CERN with around 25 million euros per year. Thanks to joint research, German universities and research institutions can not only use the CERN systems for their own experiments, but also continuously develop them. In total, more than 1200 German researchers are involved in the CERN experiments.