Antiprotonic helium and kaonic helium – A tale of two exotic helium atomsThis paper was presented at the International Conference on Precision Physics of Simple Atomic Systems, held at University of Windsor, Windsor, Ontario, Canada on 21–26 July 2008.

Abstract

Recent progress on the precision laser spectroscopy of antiprotonic helium atoms, as well as on the X-ray spectroscopy of kaonic helium atoms, are presented. These two may appear to be unrelated topics (except that both involve exotic helium atoms), but in fact a past study of kaonic helium system led to the serendipitous discovery of antiprotonic helium. Some historical background connecting these two exotic helium atoms, as well as future prospects, are discussed.