Heavy mesons with dynamical gluon on the light front

TL;DR

This paper employs the Basis Light-Front Quantization approach to study heavy mesons, incorporating quark-antiquark and quark-antiquark-gluon sectors, to compute their spectra, wave functions, and internal parton distributions, including the first gluon PDF predictions.

Contribution

It introduces a BLFQ framework with a confining potential and quark-gluon interactions to analyze heavy mesons, including gluon degrees of freedom, and predicts gluon PDFs for the first time.

Findings

Charge radii and decay constants agree with experimental data.

PDAs align with previous BLFQ results using effective one-gluon exchange.

First predictions of gluon PDFs in heavy mesons within BLFQ.

Abstract

We investigate the structure of charmonium, bottomonium, and $\rm B_c$ meson systems within the Basis Light-Front Quantization (BLFQ) approach, including both the quark-antiquark ($|q\bar{q}\rangle$) and quark-antiquark-gluon ($|q\bar{q}g\rangle$) Fock sectors. Our input light-front Hamiltonian incorporates a confining potential inspired by light-front holography, as well as the quark-gluon interaction from Quantum Chromodynamics. By adjusting model parameters to reproduce the mass spectra for low-lying states, we obtain the light-front wave functions for the heavy meson states. Based on these wave functions, we calculate electromagnetic form factors, decay constants, parton distribution amplitudes (PDAs), and parton distribution functions (PDFs) of the quarks and gluons in the heavy mesons. Our results for the charge radii and decay constants reasonably agree with experimental data and other theoretical approaches. The PDAs are consistent with the predictions from the earlier BLFQ calculations with an effective one-gluon exchange interaction. Furthermore, we present the first predictions within the BLFQ framework for the gluon PDFs in heavy mesons based on the light-front wave function in the $|q\bar{q}g\rangle$ sector.