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arXiv · 1503.05755

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

D. A. Cooke·P. Crivelli·J. Alnis·A. Antognini·B. Brown·S. Friedreich·A. Gabard·T. W. Haensch·K. Kirch·A. Rubbia·V. Vrankovic
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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.

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D. A. Cooke, P. Crivelli, J. Alnis, A. Antognini, B. Brown, S. Friedreich, A. Gabard, T. W. Haensch, K. Kirch, A. Rubbia, V. Vrankovic. 2015-03-19. Observation of positronium annihilation in the 2S state: towards a new measurement of the 1S-2S transition frequency. https://doi.org/10.1007/s10751-015-1158-4

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