Electromagnetic pion form factor in the context of the principal value method

Abstract

The pion form factor F π ( Q 2) is found in the framework of the principal value method. This method allows one to avoid the infrared singularities of the QCD running coupling constant α S( Q 2(1 − x)(1 − y)) in the soft x → 1, y → 1 region by relating it in terms of α S( Q 2). The pion wave functions Φ ASY( x) and Φ CZ( x, Q 2) are used in the calculations. The importance of infrared renormalons in such studies and the convergence of the perturbation series obtained for F π ( Q 2) are discussed.