title: Lifetime measurement of the 3P2 metastable state of strontium atoms.
abstract: We have measured the lifetime of the 5s5p 3P2 metastable state of strontium atoms by magneto-optically trapping the decayed atoms to the ground state, which allowed sensitive detection of the rare decay events. We found that the blackbody radiation-induced decay was the dominant decay channel for the state at T=300 K. The lifetime was determined to be 520(+310)(-140) s in the limit of zero temperature, arguably the longest lifetime ever determined in a laboratory environment.
authors.affiliation: Engineering Research Institute, The University of Tokyo, Bunkyo-ku, Tokyo 113-8656, Japan.
authors.forename: Masami
authors.initials: M
authors.lastname: Yasuda
authors.forename: Hidetoshi
authors.initials: H
authors.lastname: Katori