Breakdown of chiral expansion for parton distributions
arXiv:0707.2208 · doi:10.1016/j.physletb.2008.04.048
Abstract
In the framework of the chiral perturbation theory we computed two- and three-loop corrections to the pion parton distributions which posses $δ$-function singularities at x->0. This calculation explicitly demonstrates that in the region of small x ~ mpi^2/(4 pi F)^2 standard ChPT breaks down and one needs resummation of all orders. We give an example of such resummation.
10 pages, 7 figures