First Millimeter-wave Spectroscopy of the Ground-state Positronium

Abstract

We report on the first measurement of the Breit-Wigner resonance of the transition from {\it ortho-}positronium to {\it para-}positronium. We have developed an optical system to accumulate a power of over 20 kW using a frequency-tunable gyrotron and a Fabry-Pérot cavity. This system opens a new era of millimeter-wave spectroscopy, and enables us to directly determine both the hyperfine interval and the decay width of {\it p-}Ps.

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Cited by in corpus (7)

• Search for New Physics with Atoms and Molecules
• CODATA Recommended Values of the Fundamental Physical Constants: 2014
• Positronium Physics and Biomedical Applications
• Gyrotrons for High-Power Terahertz Science and Technology at FIR UF
• Three-photon-annihilation contributions to positronium energies at order $m{\alpha }^7$
• Positronium energy levels at order $m{\alpha }^7$: Product contributions in the two-photon-annihilation channel
• On the Positronium g-factor