Contributions of the C-odd axial-vector resonances to η→π0γγ and γγ→π0π0

We consider the contributions of the C-odd axial-vector resonances (b1,h1) to η→π0γγ, as well as those of the usual C-odd vector resonances (ρ,ω) and chiral loops. Inclusion of b1(1235), h1(1170), h1(1380) increases the decay width of η→π0γγ, improving the theoretical prediction. The measurement of the γγ spectrum can test our model. We also discuss the effects of these C-odd axial-vector resonances on electromagnetic interactions of neutral pions: γγ→π0π0 and electric and magnetic polarizabilities of π0