A new evaluation of the pion weak form factors (CROSBI ID 113230)
Prilog u časopisu | izvorni znanstveni rad
Podaci o odgovornosti
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.
engleski
A new evaluation of the pion weak form factors
We have used the PIBETA large-acceptance detector for a precise measurement of the pi+->e+nigama radiative decay at rest, with a broad phase space coverage. Using the CVC value for the pion vector form factor, F_V=0.0259(5), we have obtained a new value of the pion axial-vector form factor gamma=F_A/F_V=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 F_T=-0.0016(3). The question of the true nature of the observed deviations remains open pending further theoretical and experimental study.
pion weak form factor; rare decays; radiative decay
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