A search for massive neutral bosons in orthopositronium decay
نویسندگان
چکیده
We have searched for an exotic decay of orthopositronium into a single photon and a short-lived neutral boson in the hitherto unexplored mass region above 900 keV=c 2 , by noting that this decay is one of few remaining candidates which could explain the discrepancy of the orthopositronium decay-rate. A high-resolution measurement of the associated photon energy spectrum was carried out with a germanium detector to search for a sharp peak from this two-body decay. Our negative result provides the upper-limits of 2:0 10 4 on the branching ratio of such a decay in the mass region from 847 to 1013 keV=c 2 , and excludes the possibility of this decay mode explaining the discrepancy in the orthopositronium decay-rate.
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