Title

Experimental tests of lepton universality in [Formula presented] decay

Document Type

Article

Publication Date

1-1-1997

Abstract

The branching fractions for [Formula presented] [Formula presented] and [Formula presented] are measured using data collected with the CLEO detector at the CESR [Formula presented] collider: [Formula presented]=0.1776[Formula presented]0.0006[Formula presented]0.0017, [Formula presented]=0.1737[Formula presented]0.0008[Formula presented]0.0018, and [Formula presented]=0.1152[Formula presented]0.0005[Formula presented]0.0012, where the first error is statistical, the second systematic, and [Formula presented] refers to either a charged [Formula presented] or [Formula presented]. Also measured is the [Formula presented] mass, [Formula presented]=(1778.2[Formula presented]1.4) MeV. Lepton universality is affirmed by the relative branching fractions [Formula presented]/[Formula presented]=0.9777[Formula presented]0.0063[Formula presented]0.0087, [Formula presented]/[Formula presented]=0.6484[Formula presented]0.0041[Formula presented]0.0060) and the charged-current gauge coupling-constant ratios [Formula presented]=1.0026[Formula presented]0.0055, [Formula presented]=0.9990[Formula presented]0.0098). The [Formula presented] mass result may be recast as a [Formula presented] neutrino mass limit, [Formula presented]60 MeV at 95% C.L. © 1997 The American Physical Society.

Publication Name

Physical Review D - Particles, Fields, Gravitation and Cosmology

Volume Number

55

First Page

2559

Last Page

2576

Issue Number

5

DOI

10.1103/PhysRevD.55.2559

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