Observation of positronium annihilation in the 2S state: towards a new measurement of the 1S-2S transition frequency

Abstract

We report the first observation of the annihilation of positronium from the 2S state. Positronium (Ps) is excited with a two-photon transition from the 1S to the 2S state where its lifetime is increased by a factor of eight compared to the ground state due to the decrease in the overlap of the positron electron wavefunction. The yield of delayed annihilation photons detected as a function of laser frequency is used as a new method of detecting laser-excited Ps in the 2S state. This can be considered the first step towards a new high precision measurement of the 1S-2S Ps line.

arXiv comment6 pages, 3 Figures, proceedings EXA 2014, accepted for publication in Hyperfine Interactions

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• First test of $O({\alpha }^2)$ correction of the orthopositronium decay rate
• Charmonium decays: J/psi --> e+e- and eta_c --> gamma gamma
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Cited by in corpus (12)

• The Mu-MASS (MuoniuM lAser SpectroScopy) experiment
• Current and future perspectives of positronium and muonium spectroscopy as dark sectors probe
• Three-photon-annihilation contributions to positronium energies at order $m{\alpha }^7$
• Velocity selected production of $2^{3}S$ metastable positronium
• Producing long-lived $2^3\text{S}$ Ps via $3^3\text{P}$ laser excitation in magnetic and electric fields
• Experiments towards resolving the proton charge radius puzzle
• The anti-proton charge radius
• Spatial confinement of muonium atoms
• Positronium energy levels at order $m{\alpha }^7$: Product contributions in the two-photon-annihilation channel
• Positron extraction to an electromagnetic field free region
• Measurement of the ${\text{1}}^{\text{3}}{\text{S}}_{\text{1}}\to {\text{2}}^{\text{3}}{\text{S}}_{\text{1}}$ interval in positronium using field-ionization of Rydberg states
• Production and study of antideuterium with the GBAR beamline