title: New measurement of the rare decay K+ --> pi(+)&mgr;(+)&mgr;(-)
abstract: More than 400 K+-->pi(+)&mgr;(+)&mgr;(-) events were observed in a rare K+ decay experiment at the Brookhaven Alternating Gradient Synchrotron. Normalized to the K+-->pi(+)pi(+)pi(-) decay, the branching ratio is determined to be [9.22+/-0.60(stat)+/-0. 49(syst)]x10(-8). This branching ratio and the &mgr;&mgr; mass spectrum is in very good agreement with the measurement of the K+-->pi(+)e(+)e(-) decay, but deviates significantly from the previous measurement.
authors.affiliation: Brookhaven National Laboratory, Upton, New York 11973, USA.
authors.initials: H
authors.lastname: Ma
authors.initials: R
authors.lastname: Appel
authors.initials: GS
authors.lastname: Atoyan
authors.initials: B
authors.lastname: Bassalleck
authors.initials: DR
authors.lastname: Bergman
authors.initials: N
authors.lastname: Cheung
authors.initials: S
authors.lastname: Dhawan
authors.initials: H
authors.lastname: Do
authors.initials: J
authors.lastname: Egger
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authors.lastname: Eilerts
authors.initials: H
authors.lastname: Fischer
authors.initials: W
authors.lastname: Herold
authors.initials: VV
authors.lastname: Issakov
authors.initials: H
authors.lastname: Kaspar
authors.initials: DE
authors.lastname: Kraus
authors.initials: DM
authors.lastname: Lazarus
authors.initials: P
authors.lastname: Lichard
authors.initials: J
authors.lastname: Lowe
authors.initials: J
authors.lastname: Lozano
authors.initials: W
authors.lastname: Majid
authors.initials: W
authors.lastname: Menzel
authors.initials: S
authors.lastname: Pislak
authors.initials: AA
authors.lastname: Poblaguev
authors.initials: P
authors.lastname: Rehak
authors.initials: A
authors.lastname: Sher
authors.initials: JA
authors.lastname: Thompson