We observed two distinct peaks, 205-MeV/c - and 235-MeV/c -, associated with K2- and K2- decays at rest, respectively, from negative kaons stopped in liquid helium. These peaks were found to be delayed with respect to the stopping K-, showing that stopped K- mesons of about 2% fraction are trapped in metastable states with an overall lifetime of about 40 nsec. This observation provides a direct evidence for Condos trapping hypothesis for the at-rest decay components of K- and - in liquid helium.
ASJC Scopus subject areas
- Physics and Astronomy(all)