Fast decay of 23S1 positronium atoms in an MgO lined cavity
Department of Physics and Astronomy, University College London, Gower Street, WC1E 6BT, London, UK
Accepted: 15 December 2020
Published online: 15 January 2021
We report experiments in which radiatively metastable positronium (Ps) atoms entered a waveguide whose internal surfaces were lined with smoked magnesium oxide (MgO) powder. The waveguide was built such that time-delayed microwave radiation pulses, tuned to drive transitions, could be applied to the Ps ensemble. The lifetime of atoms was measured using time-delayed microwave induced decay, yielding ≈200 ns. This is considerably shorter than the Zeeman shifted lifetime of 1070 ns, indicating that Ps atoms in the state do not survive multiple collisions with MgO nanocrystals.
Key words: Positron / Positronium / Antimatter / QED / Spectroscopy
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