| Autor: |
T. Zhao, N. J. Hadley, A. Skukla, Henry Lubatti, H. Kaspar, Howard Gordon, M. E. Zeller, W. Herold, C. Alliegro, V. Chaloupka, Hong Ma, A. Deshpande, D. M. Lazarus, J. Egger, Pavel Rehak, A. M. Lee |
| Rok vydání: |
1993 |
| Předmět: |
|
| Zdroj: |
Physical Review Letters. 71:27-30 |
| ISSN: |
0031-9007 |
| DOI: |
10.1103/physrevlett.71.27 |
| Popis: |
Employing the decay chain ${\mathit{K}}^{+}$\ensuremath{\rightarrow}${\mathrm{\ensuremath{\pi}}}^{+}$${\mathrm{\ensuremath{\pi}}}^{0}$, ${\mathrm{\ensuremath{\pi}}}^{0}$\ensuremath{\rightarrow}${\mathit{e}}^{+}$${\mathit{e}}^{\mathrm{\ensuremath{-}}}$ we have observed the decay ${\mathrm{\ensuremath{\pi}}}^{0}$\ensuremath{\rightarrow}${\mathit{e}}^{+}$${\mathit{e}}^{\mathrm{\ensuremath{-}}}$. With a signal sample of \ensuremath{\approxeq}21 events we measure the branching ratio for ${\mathrm{\ensuremath{\pi}}}^{0}$\ensuremath{\rightarrow}${\mathit{e}}^{+}$${\mathit{e}}^{\mathrm{\ensuremath{-}}}$ to be (6.9\ifmmode\pm\else\textpm\fi{}2.3\ifmmode\pm\else\textpm\fi{}0.6)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}8}$, normalized to the decay ${\mathit{K}}^{+}$\ensuremath{\rightarrow}${\mathrm{\ensuremath{\pi}}}^{+}$${\mathrm{\ensuremath{\pi}}}^{0}$, ${\mathrm{\ensuremath{\pi}}}^{0}$\ensuremath{\rightarrow}${\mathit{e}}^{+}$${\mathit{e}}^{\mathrm{\ensuremath{-}}}$\ensuremath{\gamma}. This result is consistent with the unitarity lower bound and the published 90% confidence level upper limit of 13\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}8}$. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
|
