The Institute of Physics offers a wide range of research activities in the field of particle physics. Researchers collaborate with some of the largest experiments in the world to study the structure of matter both theoretically and experimentally. Furthermore, detectors are developed for research and discovery of new particles.
ATLAS
The abbreviation ATLAS stands for "A Toroidal LHC Apparatus". ATLAS is one of the four large experiments at the Large Hadron Collider (LHC) at the European Research Center for Particle Physics (CERN) in Geneva. The ATLAS collaboration includes about 3000 scientists - some working on-site at CERN, others at universities and other research institutes around the world.
ATLAS and its sister experiment CMS were used to discover the Higgs particle in summer 2012. It was the last particle in the Standard Model of particle physics to be experimentally detected. In addition, the ATLAS data are being investigated to see if they contain any clues to physics beyond the Standard Model, in particular supersymmetric particles. Such evidence has not yet been found, so the search is currently ongoing.
ATLAS at the Physikalisches Institut
More than 50 researchers from the Institute of Physics are working on the ATLAS experiment. By precisely measuring the Higgs boson or searching for new physics beyond the Standard Model, they are addressing the question of what holds the world together at its core. Visit the pages below to read more about the research focus of each group.
Belle and Belle II
Belle II is a particle physics experiment at the KEK research center in Japan. The detector records collisions of electrons and positrons at an energy of 10.58 GeV at the SuperKEKB accelerator. At this energy, one particle, the Y(4S) meson, is produced, which decays into two other particles, so-called B mesons, immediately after production.
Belle and Belle II at the Physikalisches Institut
BGOOD
The BGOOD experiment grew out of the B.1 project of a magnetic spectrometer that was originally intended to be used in combination with Crystal Barrel to detect forward-flying charged particles with high resolution over a large acceptance. The main device is a large aperture 94 t dipole magnet, the "open dipole" (OD). Shortly after the last review of CRC 16, much of the former GRAAL group joined the spectrometer project.
BGOOD at the Physikalisches Institut
The research group around Prof. Hartmut Schmieden is working on the BGOOD experiment. The focus is on meson photoproduction. Photons are fired at a target of liquid hydrogen or deuterium and the resulting excited states of the hadrons are studied. Furthermore, the group is particularly interested in exotic structures that go beyond the classical understanding of the quark model.
FASER
The ForwArd Search ExpeRiment (FASER) is a new, small experiment at the Large Hadron Collider (LHC). It was built to search for light, weakly interacting particles. These could be produced in high-energy proton-proton collisions and emitted in the extreme forward direction. Therefore, FASER is located 480 m behind the ATLAS detector in the beam direction. In addition, FASER consists of a special subdetector to detect neutrinos from LHC collisions.
FASER at the Physikalisches Institut
IAXO
The Standard Model of particle physics is an extremely successful theory that describes matter and the interactions of the smallest building blocks. However, there are several open questions that require extensions to the model. Some of these questions, e.g. the vanishing electric dipole moment of the neutron, dark matter and the observed too fast cooling of different classes of stars can be explained by the so-called Peccei-Quinn mechanism. This also predicts the existence of a light particle, the axion. The IAXO experiment is to be built at DESY in Hamburg to use a large magnet to investigate whether axions are produced in the Sun and to confirm the theory.
IAXO at the Physikalisches Institut
A GridPix detector for the detection of axions is being developed in Bonn.
Lohengrin
Both the standard model of particle physics and cosmology are very successful theories. We now know that dark matter must exist. Its properties and how to fit it into the Standard Model are some of the most pressing questions in elementary particle physics. We are developing an experimental strategy for finding a particle that could explain these questions - the dark photon. Here, it serves as a portal between the currently known Standard Model and a "dark sector" that may contain a variety of dark matter particles. The discovery of a dark photon would have implications for all of elementary particle physics. The goal of the strategy is to take into account the properties of the institute's own electron accelerator ELSA and to possibly even realize the experiment in Bonn.
More Experiments
Compass
Crystal Barrel
Experiments with the Crystal Barrel Detector at ELSA in Bonn focus on the study of photoproduced reactions on nucleons. The detector system covers 98% of 4π and has been complemented by other detector components in various setups.
Zeus
The group in Bonn was involved in several detector components of both the first and second development phases. In addition, ZEUS data are analyzed and various particle physics problems are investigated.
Gas Filled Detectors
Gaseous detectors have been used for more than 100 years to explore the smallest building blocks of our matter. Thanks to new materials and technological processes, a large number of improvements and advances in detector construction have been achieved in recent years. This has significantly improved the performance of the detectors and pushed them to the physically possible limits. At the Physikalisches Institut, GridPix detectors are developed which consist of a combination of a high-resolution pixel readout chip with a gas amplification stage. These detectors are capable of detecting single primary electrons in the gas volume, thus achieving unprecedented spatial, time, and energy resolutions.