A Novel Algorithm for Extracting the Parton Distribution Amplitude from   the Euclidean Bethe-Salpeter Wave Function
  We propose a new numerical method to compute parton distribution amplitude(PDA) from the Euclidean Bethe-Salpeter wave function. The essential step is to extract the weight function in the Nakanishi representation of the Bethe-Salpeter wave function in Euclidean space, which is an ill-posed inversion problem, via the maximum entropy method(MEM). The Nakanishi weight function as well as the corresponding light-front PDA can be well determined. We confirm the previous works on PDA computation therein the different method has been performed. 
Fei Gao, Lei Chang, Yu-xin Liu
nucl-th hep-ph