Evidence for the decay sigma+ --> pmu+ mu-.
We report the first evidence for the decay Sigma(+)-->pmu(+)mu(-) from data taken by the HyperCP (E871) experiment at Fermilab. Based on three observed events, the branching ratio is B(Sigma(+)-->pmu(+)mu(-))=[8.6(+6.6)(-5.4)(stat)+/-5.5(syst)]x10(-8). The narrow range of dimuon masses may indicate that the decay proceeds via a neutral intermediate state, Sigma(+)-->pP(0),P0-->mu(+)mu(-) with a P0 mass of 214.3+/-0.5 MeV/c(2) and branching ratio B(Sigma(+)-->pP(0),P0-->mu(+)mu(-))=[3.1(+2.4)(-1.9)(stat)+/-1.5(syst)]x10(-8).
Park
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HK
University of Michigan, Ann Arbor, Michigan 48109, USA.
Burnstein
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Chakravorty
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Chen
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Choong
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Clark
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Dukes
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Durandet
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Felix
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Fu
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Gidal
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Gustafson
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Holmstrom
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Huang
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James
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Jenkins
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Jones
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Kaplan
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Lederman
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Leros
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Longo
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Lopez
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Luebke
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Luk
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Nelson
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Perroud
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Rajaram
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Rubin
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Volk
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White
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White
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Zyla
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