Precise Measurement of theπ+→π0e+νBranching Ratio
| Autor: | L. C. Smith, K.O.H. Ziock, N. P. Kravchuk, B. A. VanDevender, J. F. Crawford, D. Mzhavia, V. V. Sidorkin, N. A. Kuchinsky, E. Frlež, A. M. Rozhdestvensky, S. M. Korenchenko, N. V. Khomutov, Yang Wang, I. Supek, W. Bertl, M. Bychkov, Barry Ritchie, Dinko Pocanic, R. C. Minehart, Zviad Tsamalaidze, Stefan Ritt, M. Daum, Wenhui Li, A. S. Korenchenko, V. A. Baranov, T. Kozlowski, Ch. Brönnimann, H. P. Wirtz |
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| Rok vydání: | 2004 |
| Předmět: | |
| Zdroj: | Physical Review Letters. 93 |
| ISSN: | 1079-7114 0031-9007 |
| Popis: | Using a large acceptance calorimeter and a stopped pion beam we have made a precise measurement of the rare ${\ensuremath{\pi}}^{+}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{0}{e}^{+}\ensuremath{\nu}$ (${\ensuremath{\pi}}_{\ensuremath{\beta}}$) decay branching ratio. We have evaluated the branching ratio by normalizing the number of observed ${\ensuremath{\pi}}_{\ensuremath{\beta}}$ decays to the number of observed ${\ensuremath{\pi}}^{+}\ensuremath{\rightarrow}{e}^{+}\ensuremath{\nu}$ (${\ensuremath{\pi}}_{e2}$) decays. We find the value of $\ensuremath{\Gamma}({\ensuremath{\pi}}^{+}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{0}{e}^{+}\ensuremath{\nu})/\ensuremath{\Gamma}(\mathrm{\text{total}})=[1.036\ifmmode\pm\else\textpm\fi{}0.004(\mathrm{s}\mathrm{t}\mathrm{a}\mathrm{t})\ifmmode\pm\else\textpm\fi{}0.004(\mathrm{s}\mathrm{y}\mathrm{s}\mathrm{t})\ifmmode\pm\else\textpm\fi{}0.003({\ensuremath{\pi}}_{e2})]\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}8}$, where the first uncertainty is statistical, the second systematic, and the third is the ${\ensuremath{\pi}}_{e2}$ branching ratio uncertainty. Our result agrees well with the standard model prediction. |
| Databáze: | OpenAIRE |
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