Naslov
Precise measurement of the Pi+ -> Pi0 e+nu branching ratio

Autori
Počanić, Dinko ; Frlež, Emil ; Baranov, V.A. ; Bertl, W. ; Bronnimann, Ch. ; Bychkov, M.: Crawford, J.F. ; Daum, M. ; Khomutov, N.V. ; Korenchenko, A.S. ; Korenchenko, S.M. ; Kozlowski, T. ; Kravchuk, N.P. ; Kuchinsky, N.A. ; Li, W. ; Minehart, R.C. ; Mzhavia, D. ; Ritchie, B.G. ; Ritt, S. ; Rozhdestvensky, A.M. ; Sidorkin, V.V. ; Smith, L.C. ; Supek, Ivan ; Tsamalaidze, Z. ; VanDevender, B.A. ; Wang, Y. ; Wirtz, H.-P. ; Ziock, K.O.H.

Izvornik
Physical review letters (0031-9007) 93 (2004);

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
pion beta decay; branching ratio; Standard Model

Sažetak
Using a large acceptance calorimeter and a stopped pion beam we have made a precise measurement of the rare Pi+ --> Pi0 e+ nu decay branching ratio. We have evaluated the branching ratio by normalizing the number of observed pion beta decays to the number of observed Pi+ --> e+ nu decays. We find the value of Gama(Pi+ --> Pi0 e+ nu)/Gama (total) = [1:036 +/- 0:004 (stat:) +/- 0:004 (syst:) +/- 0:003 ] x10-8, where the first uncertainty is statistical, the second systematic, and the third is the Pi+ -> e+ nu branching ratio uncertainty. Our result agrees well with the Standard Model prediction.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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