Factorization, Power Corrections, and the Pion Form Factor

Abstract

This letter is an investigation of the pion form factor utilizing recently developed effective field theory techniques. The primary results reported are: Both the transition and electromagnetic form factors are corrected at order $\Lambda /Q$. However, these corrections only arise due to time ordered products which are sensitive to soft components of the pion. The usual higher twist wave function corrections contribute only at order ${\Lambda }^2/Q^2$, when the quark mass vanishes. In the case of the electromagnetic form factor the $\Lambda /Q$ power correction is enhanced by a power of $1/{\alpha }_s(Q)$ relative to the leading order result of Brodsky and Lepage, if the scale $\sqrt{\Lambda Q}$ is non-perturbative. This enhanced correction could explain the discrepancy with the data.

Comments: Published, extended, version