Conference paper
A new evaluation of the pion weak form factors
Dinko Počanić (for the PIBETA collaboration)
; Physics Department, University of Virginia, Charlottesville, VA 22904-4714, USA
Abstract
We have used the PIBETA large-acceptance detector for a precise measurement of the π + → e +νγ radiative decay at rest, with a broad phase space coverage. Using the CVC value for the pion vector form factor, FV = 0.0259(5), we have obtained a new value of the pion axial-vector form factor γ = FA/FV = 0.429(14). However, significant deviations from the SM predictions are evident in our data. The discrepancy can be accounted for by introducing a pion tensor form factor of FT = −0.0016(3). The question of the true nature of the observed deviations remains open pending further theoretical and experimental study.
Keywords
pion weak form factor; rare decays; radiative decay
Hrčak ID:
305613
URI
Publication date:
1.3.2004.
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