Accès ouvert
2002
article
OpenAlex
J. Z. Bai, Y. Ban, J. G. Bian, I. Blum et autres
The branching fraction of the $\ensuremath{\psi}(2S)$ decay into ${\ensuremath{\tau}}^{+}{\ensuremath{\tau}}^{\ensuremath{-}}$ has been measured for the first time using the BES detector at the Beijing Electron-Positron Collider. The result is ${B}_{\ensuremath{\tau}\ensuremath{\tau}}=(2.71\ifmmode\pm\else\textpm\fi{}0.43\ifmmode\pm\else\textpm\fi{}0.55)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3},$ where the first error is statistical and the second is systematic. This value, …
cn, us
(code pays fourni par la source)
Accès ouvert
1998
article
OpenAlex
J. Z. Bai, J. G. Bian, I. Blum, Z. W. Chai et autres
A comparison of the rates for $\ensuremath{\psi}(2S)\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}J/\ensuremath{\psi},$ $J/\stackrel{\ensuremath{\rightarrow}}{\ensuremath{\psi}}{l}^{+}{l}^{\ensuremath{-}}$ and $J/\stackrel{\ensuremath{\rightarrow}}{\ensuremath{\psi}}$ anything is used to determine the $J/\ensuremath{\psi}$ leptonic branching fractions. The results are $B(J/\stackrel{\ensuremath{\rightarrow}}{\ensuremath{\psi}}{e}^{+}{e}^{\ensuremath{-}})=(5.90\ifmmode\pm\else\textpm\fi{}0.05\ifmmode\pm\else\textpm\fi{}0.10)%$ and $B(J/\stackrel{\ensuremath{\rightarrow}}{\ensuremath{\psi}}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}})=(5.84\ifmmode\pm\else\textpm\fi{}0.06\ifmmode\pm\else\textpm\fi{}0.10)%,$ where the first error is statistical and the second is systematic. Assuming lepton universality, the leptonic …
cn, us
(code pays fourni par la source)
Accès ouvert
1998
article
OpenAlex
J. Z. Bai, O. Bardon, I. Blum, A. Breakstone et autres
The absolute inclusive branching fraction of ${D}_{s}^{+}\ensuremath{\rightarrow}\ensuremath{\varphi}{X}^{+}$ has been measured from data collected by the BES detector at a center-of-mass energy of 4.03 GeV, corresponding to an integrated luminosity of 22.3 pb${}^{\ensuremath{-}1}$. At this energy, direct pair production ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{D}_{s}^{+}{D}_{s}^{\ensuremath{-}}$ has been observed. …
cn, us
(code pays fourni par la source)