Bottomonium in a Bethe-Salpeter-equation study

Using a well-established effective interaction in a rainbow-ladder truncation model of QCD, we fix the remaining model parameter to the bottomonium ground-state spectrum in a covariant Bethe-Salpeter equation approach and find surprisingly good agreement with the available experimental data including the $2^{--}$ ${\rm Y}(1D)$ state. Furthermore, we investigate the consequences of such a fit for charmonium and light-quark ground states.

Figure 1

The calculated bottomonium ground-state spectrum (symbols) compared to experimental data (lines).

Figure 2

The calculated charmonium ground-state spectrum (symbols) compared to experimental data (lines).

Figure 3

The calculated light-isovector ground-state spectrum (symbols) compared to experimental data (lines).

Figure 4

The calculated light-isoscalar ground-state spectrum (symbols) compared to experimental data (lines). The red symbols correspond to the $n\overline{n}$-states of our ideally mixed setup; the blue symbols denote pure $s\overline{s}$ states.