Description
Summary: I first shortly introduce the basics of quark model and lattice QCD. Then I present the results of gauge dependence of $c\bar{c}$ potentials extracted from Nambu-Bethe-Salpeter (NBS) wave functions. The potentials are obtained using the NBS amplitude method. A systematic comparison is conducted between results obtained in the Coulomb and Landau gauges. The numerical calculations are performed using 2+1 flavor QCD gauge configurations with the charm quark treated in the quenched approximation. We find that the central potentials in both gauges show excellent agreement at short distances but exhibit discrepancies at large distances. We attribute these discrepancies to insufficient suppression of excited-state contamination in the Landau gauge, which affects the linear-rising behavior of the potential at large distance. The author is grateful to F-REI (JPFR24040302) for the support of travel expenses.
