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Measurement of {eta} meson decays into lepton-antilepton pairs

Journal Article · · Physical Review. D, Particles Fields
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  1. Andrzej Soltan Institute for Nuclear Studies, Warsaw and Lodz (Poland)
  2. Stockholm University, Stockholm (Sweden)
  3. Physikalisches Institut der Universitaet Tuebingen, Tuebingen (Germany)
  4. Joint Institute for Nuclear Research, Dubna (Russian Federation)
A search for rare lepton decays of the {eta} meson was performed using the WASA detector at CELSIUS. Two candidates for double Dalitz decay {eta}{yields}e{sup +}e{sup -}e{sup +}e{sup -} events are reported with a background of 1.3{+-}0.2 events. This allows to set an upper limit to the branching ratio of 9.7x10{sup -5} (90% CL). The branching ratio for the decay {eta}{yields}e{sup +}e{sup -}{gamma} is determined to (7.8{+-}0.5{sub stat}{+-}0.8{sub syst})x10{sup -3} in agreement with world average value. An upper limit (90% CL) for the branching ratio for the {eta}{yields}e{sup +}e{sup -} decay is 2.7x10{sup -5} and a limit for the sum of the {eta}{yields}{mu}{sup +}{mu}{sup -}{mu}{sup +}{mu}{sup -} and {eta}{yields}{pi}{sup +}{pi}{sup -}{mu}{sup +}{mu}{sup -} decays is 3.6x10{sup -4}.
OSTI ID:
21039006
Journal Information:
Physical Review. D, Particles Fields, Journal Name: Physical Review. D, Particles Fields Journal Issue: 3 Vol. 77; ISSN PRVDAQ; ISSN 0556-2821
Country of Publication:
United States
Language:
English

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