{"paper":{"title":"Precision Measurement of Orthopositronium Decay Rate Using SiO_2 Powder","license":"","headline":"","cross_cats":[],"primary_cat":"hep-ex","authors_text":"O. Jinnouchi, S. Asai, T. Kobayashi","submitted_at":"2003-08-10T04:07:02Z","abstract_excerpt":"The intrinsic decay rate of orthopositronium formed in ${\\rm SiO_2}$ powder is measured using the direct $2\\gamma$ correction method such that the time dependence of the pick-off annihilation rate is precisely determined using high energy-resolution germanium detectors. As a systematic test, two different types of ${\\rm SiO_2}$ powder are used with consistent findings. The intrinsic decay rate of orthopositronium is found to be $7.0396\\pm0.0012 (stat.)\\pm0.0011 (sys.)\\mu s^{-1}$, which is consistent with previous measurements using ${\\rm SiO_2}$ powder with about twice the accuracy. Results ag"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"hep-ex/0308030","kind":"arxiv","version":1},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}