Free Meson Seminars

Distribution amplitudes from Euclidean correlation functions

by Prof. Gunnar Bali (University of Regensburg)

Thursday, February 22, 2018 from to (Asia/Kolkata)
at AG69
Parton distribution functions (PDFs) and amplitudes (DAs) are defined near the light front frame. Within the parton model the former correspond to probability densities and the latter to wavefunctions of a given hadron. While PDFs are needed in the description of inclusive processes, DAs are important for exclusive processes like the photoproduction of pions. 

Within QCD, PDFs and DAs are defined as expectation values of non-local light front operators. However, Mellin moments of PDFs and DAs can be related to expectation values of local operators, making their non-perturbative evaluation  in lattice simulations in Euclidean spacetime viable. However, to reconstruct these objects, more than just the lowest few moments are needed. Recently, new methods of directly computing PDFs on the lattice have been suggested. I will briefly review these developments and related problems, before describing an ongoing direct evaluation of the pion DA from Euclidean Green functions in coordinate space as the "easiest" realization of these novel methods.