Precise Measurement of the Pion Axial Form Factor in theπ+→e+νγDecay

e(+)nugamma in three broad kinematic regions using the PIBETA detector and a stopped pion beam. Based on Dalitz distributions of 41 601 events we have evaluated absolute pi-->enugamma branching ratios in the three regions. Minimum chi(2) fits to the integral and differential (E(e(+)),E(gamma)) distributions result in the axial-to-vector weak form factor ratio of gamma identical with F(A)/F(V)=0.443(15), or F(A)=0.0115(4) with F(V)=0.0259. However, deviations from standard model predictions in the high-E(gamma)-low-E(e(+)) kinematic region indicate the need for further theoretical and experimental work. -->
ISSN: 1079-7114
0031-9007
Přístupová URL adresa: https://explore.openaire.eu/search/publication?articleId=doi_________::2569e506428d46bdadf61a5f82cb2a46
https://doi.org/10.1103/physrevlett.93.181804
Rights: OPEN
Přírůstkové číslo: edsair.doi...........2569e506428d46bdadf61a5f82cb2a46
Autor: V. Baranov, N. A. Kuchinsky, Zviad Tsamalaidze, A. S. Korenchenko, Stefan Ritt, N. V. Khomutov, N. P. Kravchuk, Emil Frlez, L. C. Smith, K.O.H. Ziock, V. V. Sidorkin, M. Bychkov, W. Bertl, E. P. Velicheva, H. P. Wirtz, Barry Ritchie, D. Mzhavia, B. A. VanDevender, R. C. Minehart, S. M. Korenchenko, A. M. Rozhdestvensky, Dinko Pocanic, Wenhui Li, T. Kozlowski, I. Supek, Yang Wang
Rok vydání: 2004
Předmět:
Zdroj: Physical Review Letters. 93
ISSN: 1079-7114
0031-9007
Popis: We have studied radiative pion decays pi(+)-->e(+)nugamma in three broad kinematic regions using the PIBETA detector and a stopped pion beam. Based on Dalitz distributions of 41 601 events we have evaluated absolute pi-->enugamma branching ratios in the three regions. Minimum chi(2) fits to the integral and differential (E(e(+)),E(gamma)) distributions result in the axial-to-vector weak form factor ratio of gamma identical with F(A)/F(V)=0.443(15), or F(A)=0.0115(4) with F(V)=0.0259. However, deviations from standard model predictions in the high-E(gamma)-low-E(e(+)) kinematic region indicate the need for further theoretical and experimental work.
Databáze: OpenAIRE
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