Measurement of Orthopositronium Decay Rate Using SiO2 Powder: Integration of Thermalization into Time Spectrum

2000/11/03 by O. Jinnouchi, S. Asai, Jinnouchi, O. +3
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Experiment (hep-ex) #hep-ex

paper · pdf · doi:10.48550/arxiv.hep-ex/0011011

8 pages Latex with 7 eps figures, submitted to EPJD

arxiv created 2000/11/03 · arxiv updated 2009/11/30

Abstract

The intrinsic decay rate of orthopositronium (o-Ps) formed in SiO₂ powder was measured using a modified method which determined the time dependence of the pick-off annihilation rate using high-energy-resolution germanium detectors. That is, the main systematic error due to thermalization was accounted for and integrated into the time spectrum fitting procedure. The averaged value was found to be lambda_(o-Ps)=7.0399+0.0020-0.0021(stat.) +-0.0015(sys.) mu s^-1, which agrees well with the O(alpha²) QED prediction; varying 2.8-4.2 experimental standard deviations from other measurements.

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