학술논문

A measurement of the electronic widths Γ ee of the ϒ(1S), ϒ(2S), and ϒ(4S) resonances, and of the total decay width Γ of the ϒ(4S)
Document Type
Original Paper
Source
Zeitschrift für Physik C Particles and Fields. December 1995 65(4):619-625
Subject
Language
English
ISSN
0170-9739
1431-5858
Abstract
The partial decay width into electrons, Γee, of the ϒ(1S) and ϒ(2S) resonances have been measured with the detector ARGUS at thee+e storage ring DORISII of DESY. Applying the formula of Kuraev and Fadin for the radiative corrections we find: Γee(ϒ(1S))= (1.32±0.04±0.03) keV and Γee(ϒ(2S))=(0.52±0.03±0.01) keV. The total decay width of the ϒ(4S) resonance and its partial width into electrons have been determined as well. Fitting the data with a generalized Breit-Wigner function with an energy dependent decay width Γ(s) and a mass shift functionm(s), we obtain the following resonance parameters: Γ(M2)=(10.0±2.8±2.7) MeV, Γee=(0.28±0.05±0.01)keV andBee=(2.77±0.50±0.49)·10−5. We argue that the disagrecment of this result with the world average originates from our more adequate parametrization of the observed ϒ(4S) resonance cross section.