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arXiv · hep-ex/0312030

Precise Measurement of the Pi+ -> Pi0 e+ nu Branching Ratio

D. Pocanic·E. Frlez·V. A. Baranov·W. Bertl·C. Broennimann·M. Bychkov·J. F. Crawford·M. Daum·N. V. Khomutov·A. S. Korenchenko·S. M. Korenchenko·T. Kozlowski·N. P. Kravchuk·N. A. Kuchinsky·W. Li·R. C. Minehart·D. Mzhavia·B. G. Ritchie·S. Ritt·A. M. Rozhdestvensky·V. V. Sidorkin·L. C. Smith·I. Supek·Z. Tsamalaidze·B. A. VanDevender·Y. Wang·H. -P. Wirtz·K. O. H. Ziock
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Abstract

Using a large acceptance calorimeter and a stopped pion beam we have made a precise measurement of the rare Pi+ -> Pi0 e+ Nu,(pi_beta) decay branching ratio. We have evaluated the branching ratio by normalizing the number of observed pi_beta decays to the number of observed Pi+ -> e+ Nu, (pi_{e2}) decays. We find the value of Gamma(Pi+ -> Pi0 e+ Nu)/Gamma(total) = [1.036 +/- 0.004(stat.) +/- 0.004(syst.) +/- 0.003(pi_{e2})] x 10^{-8}$, where the first uncertainty is statistical, the second systematic, and the third is the pi_{e2} branching ratio uncertainty. Our result agrees well with the Standard Model prediction.

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D. Pocanic, E. Frlez, V. A. Baranov, W. Bertl, C. Broennimann, M. Bychkov, J. F. Crawford, M. Daum, N. V. Khomutov, A. S. Korenchenko, S. M. Korenchenko, T. Kozlowski, N. P. Kravchuk, N. A. Kuchinsky, W. Li, R. C. Minehart, D. Mzhavia, B. G. Ritchie, S. Ritt, A. M. Rozhdestvensky, V. V. Sidorkin, L. C. Smith, I. Supek, Z. Tsamalaidze, B. A. VanDevender, Y. Wang, H. -P. Wirtz, K. O. H. Ziock. 2004-07-17. Precise Measurement of the Pi+ -> Pi0 e+ nu Branching Ratio. https://doi.org/10.1103/physrevlett.93.181803

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