Heavy quark distribution function in hadrons

TL;DR

This paper uses QCD sum rules to analyze the moments of heavy quark distribution functions in mesons, highlighting the effectiveness of the heavy mass expansion for bottom quarks and the need for higher-order terms for charm quarks.

Contribution

It provides a detailed comparison of the heavy mass expansion's accuracy for different quark masses in heavy mesons using QCD sum rules.

Findings

Heavy mass expansion is accurate for b quarks.

Higher than (1/m_c)^2 terms are needed for c quarks.

QCD sum rules effectively analyze heavy quark distributions.

Abstract

The moments of the heavy quark-parton distribution functions in a heavy pseudoscalar meson, obtained in QCD sum rules, are expanded in the inverse heavy quark. Comparison with the finite mass results reveals that while the heavy mass expansion works reasonably well for the $b$ quark, one has to take into account terms of higher than $(1/m_c)^2$ order for the $c$ quark.