S-wave flavor-singlet meson mixing in QCD with light and charm quarks

TL;DR

This study explores the mixing of flavor-singlet light mesons and charmonium in QCD, revealing significant operator correlations and providing insights into the energy spectrum and state compositions in S-wave channels.

Contribution

It presents a detailed lattice QCD analysis of flavor-singlet meson mixing, including operator correlations, spectrum extraction, and overlap calculations, which advances understanding of meson structure.

Findings

Significant non-zero correlations between different quark content operators.

Successful extraction of low-lying energy spectrum using GEVP.

All operator types contribute to the states of interest.

Abstract

We investigate the mixing between flavor-singlet light meson and charmonium operators in the S-wave channels, i.e. pseudo-scalar and vector channel, at two different pion masses. We measure statistically significant non-zero correlations between operators with different quark content corresponding to off-diagonal entries of a flavor-singlet mixing correlation matrix. By solving a GEVP we extract the low-lying energy spectrum and compare it with the one obtained by the different types of operators separately. We also calculate the overlaps between the states created by different operators and the energy eigenstates of the theory and find that all types of operators contribute to resolve the states of interest.