On quarkonium masses in 3D non-commutative space

We modify the calculation of quarkonium masses using the radial WKB and Pekeris-type approximations for the case of three-dimensional, rotationally invariant non-commutative space. We obtain corrections to the charmonium ($\text{c}\bar{\text{c}}$), bottomonium ($\text{b}\bar{\text{b}}$) and bottom-charmed meson ($\text{c}\bar{\text{b}}$) masses due to the discrete short distance structure of the space introduced by the space non-commutativity. For the fundamental length at the Planck scale we obtain relative correction at the order of ${10}^{-39}$, and taking into account the current experimental data, we obtain the upper bound at the order of ${10}^{-18}\text{ m}$ for the fundamental length scale of space.