Pion form factors with improved infrared factorization

Abstract

We calculate electromagnetic pion form factors with an analytic model for ${\alpha }_{\mathrm{s}}(Q^2)$ which is infrared (IR) finite without invoking a ``freezing'' hypothesis. We show that for the asymptotic pion distribution amplitude, $F_{{\pi }^0{\gamma }^{\ast }\gamma }$ agrees well with the data, whereas the IR-enhanced hard contribution to $F_{\pi }$ and the soft (nonfactorizing) part can jointly account for the data.

Comments: 12 pages; 3 figures as PS files (1 figure added); modified text; added references. To appear in Phys. Lett. B