Abstract
This work presents experimental measurements of the and transition rates for helium. It completes the determination of the decay rates to the ground state from the manifold and also completes the decay rates for the metastable rare-gas series. The rate of photon emission from the and states to the ground state is measured relative to the emission rate from the transition, which we have determined previously for the first time. The value for the transition is . An upper bound of is placed on the emission rate for the transition, which is predicted to be strictly forbidden. Along with our previous measurement of the lifetime, the manifold decay rates are in excellent agreement with current quantum-electrodynamic theory.
- Received 22 June 2009
DOI:https://doi.org/10.1103/PhysRevA.80.044501
©2009 American Physical Society