Research at the group of Prof. Dr. A. Khoukaz

Prof. Dr A. Khoukaz’s research group focuses on the production and decays of mesons and exotic particles produced in matter-antimatter interactions, such as electron-positron collisions and, in future, antiproton-proton collisions. Other key areas of research include the measurement of the proton-proton cross-section and work on an experiment currently under construction in Mainz, aimed at carrying out high-precision measurements in the field of hadron and nuclear physics.

Simulated BESIII event in the BESIII Event Display.
© AG Khoukaz

One of our research group’s key areas of focus is the investigation of the charmonium spectrum and possible exotic particle states, such as the Y(4260). To this end, measurements are currently being carried out at the BESIII experiment, which is operated at the BEPC-II electron-positron collider at the Institute of High Energy Physics in Beijing. Electrons and positrons are accelerated in the Linac to center-of-mass energies between 1.84 and 5.6 GeV and injected into the two storage rings of BEPCII. There, they are brought to collision in the center of the BESIII detector.

An animation of the interference between a resonant and a non-resonant process for different phase differences φ. In the resonant process, a particle is produced which can be described in the energy spectrum √s by a Breit-Wigner (BW) distribution. The contribution of the non-resonant process is modelled by a constant a.
© AG Khoukaz

Other major areas of research for our group are the KOALA and PANDA experiments, which are being set up at the future HESR antiproton storage ring at the FAIR accelerator centre in Darmstadt. In future, this large-scale experiment will carry out, amongst other things, precision measurements of charm mesons and exotic particles.

CAD drawings of the planned PANDA Experiment (left) and KOALA@CaveC (right).
© AG Khoukaz

For the KOALA and PANDA experiments, the use of jet targets is planned; these are being constructed by our research group and have been tested and optimised at various sites and particle accelerators, such as the COSY cooler synchrotron in Jülich. There, important measurements were carried out in conjunction with the other components installed at COSY, ensuring that the cluster-jet target can be used optimally in the future PANDA experiment. A prototype of this target has been in operation at our institute for many years and is used for systematic investigations into cluster production and new diagnostic tools.

MAGIX Target setup (left) and argon filament in the interaction chamber (right) at A1 Experiment at electron accelerator MAMI.
© AG Khoukaz

Another area of application for jet targets is the MAGIX experiment at the future MESA electron accelerator in Mainz. Here, supersonic gas jets and filament targets are generated using various gaseous elements, which are used to investigate key research areas such as the search for dark photons or the high-precision measurement of the radius of protons.

Target source (left) and skimmer chamber of the Cluster-Jet Prototype.
© AG Khoukaz

In addition to the ongoing optimisation and research into cluster and gas-jet targets, the Khoukaz Research Group is also developing filament and droplet targets, which can be used as alternatives to the aforementioned target types. Special techniques ensure that the droplet target produces a regular and uniform stream of droplets, whereas the filament target produces a frozen filament – for example, made of hydrogen – which is thinner than a human hair.