title: Improved Measurement of the π→eν Branching Ratio.
abstract: A new measurement of the branching ratio R_{e/μ}=Γ(π^{+}→e^{+}ν+π^{+}→e^{+}νγ)/Γ(π^{+}→μ^{+}ν+π^{+}→μ^{+}νγ) resulted in R_{e/μ}^{exp}=[1.2344±0.0023(stat)±0.0019(syst)]×10^{-4}. This is in agreement with the standard model prediction and improves the test of electron-muon universality to the level of 0.1%.
authors: Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de Mexico, Distrito Federal 04510 México.
authors: A
authors: A
authors: Aguilar-Arevalo
authors: Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan.
authors: M
authors: M
authors: Aoki
authors: Physics Department, Virginia Tech, Blacksburg, Virginia 24061, USA.
authors: M
authors: M
authors: Blecher
authors: Physics Department, University of Glasgow, Glasgow G12 8QQ, United Kingdom.
authors: D I
authors: DI
authors: Britton
authors: Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada.
authors: D A
authors: DA
authors: Bryman
authors: Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada.
authors: D
authors: D
authors: Vom Bruch
authors: Department of Engineering Physics, Tsinghua University, Beijing 100084, People's Republic of China.
authors: S
authors: S
authors: Chen
authors: Physics Department, Arizona State University, Tempe, Arizona 85287, USA.
authors: J
authors: J
authors: Comfort
authors: Department of Engineering Physics, Tsinghua University, Beijing 100084, People's Republic of China.
authors: M
authors: M
authors: Ding
authors: TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada.
authors: L
authors: L
authors: Doria
authors: Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada.
authors: S
authors: S
authors: Cuen-Rochin
authors: TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada.
authors: P
authors: P
authors: Gumplinger
authors: University of Northern British Columbia, Prince George, British Columbia V2N 4Z9, Canada.
authors: A
authors: A
authors: Hussein
authors: KEK, 1-1 Oho, Tsukuba-shi, Ibaraki 305-0801, Japan.
authors: Y
authors: Y
authors: Igarashi
authors: Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan.
authors: S
authors: S
authors: Ito
authors: Brookhaven National Laboratory, Upton, New York 11973-5000, USA.
authors: S H
authors: SH
authors: Kettell
authors: TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada.
authors: L
authors: L
authors: Kurchaninov
authors: Brookhaven National Laboratory, Upton, New York 11973-5000, USA.
authors: L S
authors: LS
authors: Littenberg
authors: Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada.
authors: C
authors: C
authors: Malbrunot
authors: TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada.
authors: R E
authors: RE
authors: Mischke
authors: TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada.
authors: T
authors: T
authors: Numao
authors: Physics Department, University of Glasgow, Glasgow G12 8QQ, United Kingdom.
authors: D
authors: D
authors: Protopopescu
authors: TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada.
authors: A
authors: A
authors: Sher
authors: Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada.
authors: T
authors: T
authors: Sullivan
authors: TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia V6T 2A3, Canada.
authors: D
authors: D
authors: Vavilov
authors: Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan.
authors: K
authors: K
authors: Yamada