Hannover 2003 – wissenschaftliches Programm
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A: Atomphysik
A 17: Postersitzung 2
A 17.3: Poster
Donnerstag, 27. März 2003, 16:00–18:30, Poster
Towards a new Measurement of the Decay Rate of the Positronium Negative I on — •F. Fleischer1, M. Lestinsky1, G. Gwinner1, K. Degreif1, V. Liechtenstein2, F. Plenge1, and D. Schwalm1 — 1MPI für Kernphysik, 69029 Heidelberg — 2Kurtchatov Institute, Moscow
Consisting of two electrons and a positron, the
positronium negative ion (Ps−) represents the simplest
three-body-system with a bound state. Being free from perturbations
due to strong interactions the system provides interesting
opportunities to test our understanding of the three-body problem and
quantum electrodynamics. Previous experiments have so far only proved
the existence of Ps− [1] and determined the decay rate with 4%
accuracy [2]. To allow for a test of radiative corrections and
bound-state contributions to the decay rate an increase in precision
of at least one order of magnitude is necessary. Of particular
interest would be also the measurement of the
3γ/2γ-branching ratio because of its relevance to the
ortho-Ps lifetime. An experiment has been built up at the MPI für
Kernphysik to investigate the decay rate and other properties of
Ps− in more detail. The first preliminary measurements as well as
current improvements to the existing set-up will be discussed.
[1] A.P. Mills, Jr., Phys. Rev. Lett. 46, 717(1981)
[2] A.P. Mills, Jr., Phys. Rev. Lett. 50, 671(1983)