An Analysis on the Parton Distribution Functions of Heavy Mesons

TL;DR

This paper models the parton distribution functions of heavy mesons like kaons using the light-cone quark model, performs QCD evolution, and predicts structure functions and Drell-Yan cross sections for future experiments.

Contribution

It introduces a detailed analysis of heavy meson PDFs with NLO QCD evolution and provides predictions for upcoming collider experiments.

Findings

Heavy constituents carry more momentum than lighter ones in heavy mesons.

NLO structure functions for the kaon are predicted at energies relevant for the EIC.

Drell-Yan cross sections are computed for various nuclear targets, showing dominance of heavy quark contributions.

Abstract

In this work, we investigate the constituent parton distribution functions (PDFs) of the kaon and heavy pseudoscalar mesons within the light-cone quark model. Starting from the initial scale quark and antiquark PDFs, obtained by evaluating the quark-quark correlation functions for individual mesons, we perform quantum chromodynamics (QCD) evolution to determine the partonic structure at higher energy scales. The QCD evolution has been carried out through the next-to-leading order (NLO) Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (DGLAP) equations. We further compute the average longitudinal momentum fractions carried by the individual constituents both at the model scale and evolved scale. In addition, the NLO structure functions for the kaon are predicted at higher energy scales relevant for the upcoming Electron-Ion Collider (EIC). For the COMPASS++/AMBER experiment, we further present detailed predictions for the NLO Drell-Yan cross sections corresponding to both isospin states of the kaon, employing Carbon, Tungsten, and Aluminum as nuclear targets. We demonstrate the dominance of the heavy constituents over the lighter constituents within their heavy mesons in terms of their possessed momentum fractions.