Double parton distributions in the pion from lattice QCD

TL;DR

This study uses lattice QCD to explore double parton distributions in the pion, revealing spatial and polarization correlations and examining the factorization assumption, with results varying by quark mass.

Contribution

First lattice QCD analysis of double parton distributions in the pion, linking Mellin moments to matrix elements and analyzing correlations and factorization.

Findings

Observed spatial and polarization correlations depend on quark mass

Achieved good statistical signals for most Wick contractions

Examined the validity of the factorization assumption in DPDs

Abstract

We perform a lattice study of double parton distributions in the pion, using the relationship between their Mellin moments and pion matrix elements of two local currents. A good statistical signal is obtained for almost all relevant Wick contractions. We investigate correlations in the spatial distribution of two partons in the pion, as well as correlations involving the parton polarisation. The patterns we observe depend significantly on the quark mass. We investigate the assumption that double parton distributions approximately factorise into a convolution of single parton distributions.