Double parton distributions in the nucleon on the lattice: Flavor interference effects

TL;DR

This study computes the first Mellin moment of double parton distributions in the proton on the lattice, focusing on flavor interference effects and comparing results with quark model predictions.

Contribution

It provides the first lattice calculation of flavor interference effects in the first Mellin moment of DPDs for the unpolarized proton.

Findings

Results show flavor interference effects are significant.

Dependence on quark polarization is analyzed.

Comparison with quark models highlights differences.

Abstract

Information about double parton distributions (DPDs) can be obtained by calculating four-point functions on the lattice. We continue our study on the first DPD Mellin moment of the unpolarized proton by considering interference effects w.r.t. the quark flavor. In our simulation we employ an $n_f = 2 + 1$ ensemble with inverse coupling $\beta = 3.4$, and pseudoscalar masses of $m_\pi = 355~\mathrm{MeV}$ and $m_K = 441~\mathrm{MeV}$. The results are converted to the $\overline{\mathrm{MS}}$-scheme at the scale $\mu = 2~\mathrm{GeV}$. We analyze the dependence of the considered Mellin moments on the quark polarization and compare our results with quark model predictions.