CERN-Kjerne- og partikkelforskning

The AEGIS experiment, situated at the Antimatter Decelerator (AD) at CERN aim to be the first experiment to directly measure the Earth's gravitational acceleration of antimatter. To achieve this the AEGIS collaboration has to produce a pulsed anti-hydrogen beam for the first time and to perform the very first direct detection of anti-hydrogen annihilation on the detector surface. Beyond these important results it will also provide long-term anti-matter spectroscopy measurements. The Norwegian contribution to the AEGIS experiment has the last years been the development of a position detector, a key element in the AEGIS experiment, which will be responsible for the measurement of gravitational effects on anti-hydrogen. In addition, we have preformed research on silicon sensors with anti-protons, built a new secondary beam line for further detector and materials studies. During the latest part of the project period we have also contributed to the research of the formation of anti-hydrogen and participated in the operation of the experiment. A breakthrough was published in February 2021, when one for the first time could show pulsed production of anti-hydrogen atoms. At the same time those atoms can also be manipulated, by lasers or external fields. It will also be possible to form other antiprotons atoms in the same way. A big step towards measuring the effect of gravity on anti-matter.

Scientific impact: - First production of antihydrogen in pulsed mode - A novel climate chamber and laser setup for detector tests - Novel positronium and laser developments - Novel simulation software for studies of detection of anti-hydrogen - 32 publications, as well as a large number of conference and collaboration talks etc. - 2 PhD degrees and 3 student projects (bachelor and master level) Societal impact: - Education and training of Bachelor, Master and PhD students, important for recruitment to industry. Knowledge on physics, detectors, computing and lasers as in this project has proved to be attractive. - Knowledge transfer from CERN to Norway. Norwegian students have been trainied at CERN in technologies and processes they would otherwise not have access to. - The chip developed potentially results in new applications - Large thin silicon strip detectors may be important for future detector technologies and for medicine or space.

The weak equivalence principle (WEP) implies that the gravitational interactions of matter and anti-matter are exactly identical. This assertion, being a fundamental consequence of general relativity, has never been experimentally verified; in fact the gravitational force on anti-matter system has never been directly observed. Consequently, a first, even modest precision measurement of the gravitational interactions of anti-matter is very interesting Observing the gravitational effects on anti-Hydrogen is a substantial experimental challenge, requiring the integration of techniques from two distinct fields of physics: atomic physics, and particle detectors. In Norway, the collaboration between these two fields is ensured by the Norwegian participation in the AEGIS experiment at CERN. The AEGIS collaboration initially approached the Norwegian groups, inviting us to participate in the experiment and take the main responsibility for its position sensitive detector, a silicon detector, which is a crucial part of the apparatus. Thanks to a successful FRINTATEK grant we have the last four years developed such a detector, performed unique detector research with anti-matter and helped develop and operate the main apparatus. We have also been able to propose and successfully install a completely new beam line dedicated to detector research with anti-matter With the delay of the main experiment (e.g. due to LHC upgrade) we would like to continue our research in AEGIS in order to take part in the gravitational measurement of anti-Hydrogen. In addition, we would like to take further advantage of our newly gained expertise in anti-matter detection and the new tools to further advance our research which we have developed and which is now ready to be used and thus continue to play a major role in this international collaboration.