PROF. FRANÇOISE MUELHAUSER
Visiting Research Assistant Professor
Nuclear Physics Laboratory
University of Illinois at Urbana-Champaign
Based at the Paul Scherrer Institute, Switzerland
 

Exotic Atoms:   A Tool for Nuclear and Atomic Physics

When heavy negative particles (m^-,  p^-, K^-, ,…) stop in matter, they form exotic atoms usually in highly excited states. The exotic-atom formation is followed by an atomic cascade consisting of multi-step transitions to lower atomic states. Hadronic atoms, like p^-Z, K^-Z, Z, finish their atomic cascade by being absorbed by the nuclei with much higher probability than by reaching the ground state. Muonic atoms, like m^-Z, (where the nuclear absorption is weak) deexcite to the ground state and engage in various reactions (muon catalyzed fusion, muon transfer, molecular formation) with initial conditions determined by the atomic cascade.
 

Due to their size, exotic atoms are the perfect tool to probe nuclear properties at low energies. As an example, the muonic hydrogen Lamb shift experiment is aiming at measuring the proton charge radius. Other examples like kaonic hydrogen transitions to the ground states allow us to determine strong interaction effect. These examples will be shown during my presentation.

Coffee will be available in the Physics Common Room
prior to the Colloquium