TY - JOUR
T1 - New limits on exotic two-body decay of orthopositronium
AU - Orito, S.
AU - Yoshimura, K.
AU - Haga, T.
AU - Minowa, M.
AU - Tsuchiaki, M.
PY - 1989
Y1 - 1989
N2 - Motivated by the recently reported discrepancy between measured and theoretical values for the orthopositronium lifetime, we have searched for exotic decay of orthopositronium into plus a long-lived neutral particle X, in the hitherto unexplored mass region of mx below 100 keV. Our negative result provides new upper limits of 6.4×10-5 to 7.6×10-6 on the branching ratio of such decay. Consequently we exclude the hypothesis of Samuel, i.e., that a new pseudoscalar particle with mass less than 5.7 keV is responsible for the discrepancy of the orthopositronium lifetime.
AB - Motivated by the recently reported discrepancy between measured and theoretical values for the orthopositronium lifetime, we have searched for exotic decay of orthopositronium into plus a long-lived neutral particle X, in the hitherto unexplored mass region of mx below 100 keV. Our negative result provides new upper limits of 6.4×10-5 to 7.6×10-6 on the branching ratio of such decay. Consequently we exclude the hypothesis of Samuel, i.e., that a new pseudoscalar particle with mass less than 5.7 keV is responsible for the discrepancy of the orthopositronium lifetime.
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U2 - 10.1103/PhysRevLett.63.597
DO - 10.1103/PhysRevLett.63.597
M3 - Article
AN - SCOPUS:4243655726
VL - 63
SP - 597
EP - 600
JO - Physical Review Letters
JF - Physical Review Letters
SN - 0031-9007
IS - 6
ER -