Carvalho, W. S.Antunes, ACBDeCastro, A. S.2014-05-272014-05-271997-01-20Modern Physics Letters A, v. 12, n. 2, p. 121-125, 1997.0217-7323http://hdl.handle.net/11449/132312The mass splitting of the pseudoscalar mesons η and η′ is approached by taking into account the SU(3)-flavor symmetry breaking and annihilation effects. An extended version of the Schwinger sum rule and a mixing angle equal to -19.51° are obtained.121-125engArtigo10.1142/S021773239700011XWOS:A1997WK70800004Acesso restrito2-s2.0-00402577375811700083195480