Quark distributions in extended QCD sum rule approach

TL;DR

This paper introduces an improved QCD sum rule method for calculating quark distributions in hadrons, specifically addressing previous accuracy issues and validating results with pion data from Drell-Yan experiments.

Contribution

It presents a novel approach using double Borel transformation to enhance the accuracy of quark distribution calculations in QCD sum rules.

Findings

Valence quark distributions in the pion agree with experimental data.

The method reduces background transition effects, improving calculation precision.

Results support the validity of the extended sum rule approach.

Abstract

The improved calculation method of quark distributions in hadrons in the framework of QCD sum rules is presented. The imaginary part of the virtual photon scattering amplitude on some hadronic current is considered in the case, when initial and final virtualities of the current $p^2_1$ and $p^2_2$ are different, $p^2_1\not= p^2_2$. The double Borel transformation in $p^2_1, p^2_2$ is applied to the sum rule, killing background non-diagonal transition terms, which deteriorated the accuracy in the previous calculations. Valence quark distributions in the pion were found in a good agreement with the data, determined from the Drell-Yan process.