Anikin, I. V.Dorokhov, A. E.Tomio, L. [UNESP]2014-05-272014-05-272001-07-01Physics of Atomic Nuclei, v. 64, n. 7, p. 1329-1336, 2001.1063-7788http://hdl.handle.net/11449/66539The leading-twist pion-distribution amplitude is obtained at a low normalization scale of order ρc (inverse average size of an instanton). Pion dynamics, consistent with gauge invariance and low-energy theorems, is considered within the instanton vacuum model. The results are QCD-evolved to higher momentum-transfer values and are in agreement with recent data from CLEO on the pion transition form factor. It is also shown that some previous calculations violate the axial Ward-Takahashi identity. © 2001 MAIK Nauka/Interperiodica.1329-1336engArtigo10.1134/1.1389562Acesso restrito2-s2.0-0035537339