Corrections to quarkonium 1S energy level at O(alpha_S^4 m) from non-instantaneous Coulomb vacuum polarization

Y. Kiyo, Y. Sumino

We calculate O(alpha_S^4 m) and O(alpha_S^4 m log(alpha_S)) corrections to the quarkonium 1S energy level analytically, which have been overlooked in recent studies. These are the…