ASACUSA experiment studies new exotic atom at PSI
"It’s like an helium-4 atom, but with an electron and a negative pion. Exotic atom spectroscopy is a tool for precise measurement of the replacement particle properties and to search for phenomena beyond the Standard Model "
The ASACUSA collaboration has taken experimental equipment from CERN to the Paul Scherrer Institut (PSI), Zurich, to create a theoretically predicted but never before verified exotic atom and made first measurements of how it absorbs and emits light. The results were now published in Nature. These are the first time spectroscopic measurements on an exotic atom containing a meson (a particle made of two quarks). Such atoms usually have very short lifetimes, but they are excellent tools for studying the properties of the replacement particle and to search for physics phenomena not predicted by the Standard Model of particle physics.
In the case now published, the exotic atom was consists of a nucleus from an isotope of helium (helium-4), an electron and a negatively charged pion in a high-lying energy state. Its lifetime is more than a thousand times longer than any other atom containing a pion. The team took negatively charged pions provided by PSI’s 590 MeV ring cyclotron facility and focused them using a magnet into a target containing superfluid helium. Both the target and the magnet were made at CERN and brought to PSI for this study.
Read more: CERN press release