Dielectron widths of the S-, D-vector bottomonium states

Abstract

The dielectron widths of Y(nS)(n = 1, …, 7) and vector decay constants are calculated using the relativistic string Hamiltonian with a universal interaction. For Y(nS) (n = 1, 2, 3) the dielectron widths and their ratios are obtained in full agreement with the latest CLEO data. For Y(10580) and Y(11020) a good agreement with experiment is reached only if the 4S-3D mixing (with a mixing angle θ = 27°± 4°) and 6S-5D mixing (with θ = 40°±5°) are taken into account. The possibility to observe higher “mixed D-wave” resonances, \( \tilde \Upsilon \)(n 3 D 1) with n = 3, 4, 5 is discussed. In particular, \( \tilde \Upsilon \)(≈11120), originating from the pure 53 D 1 state, can acquire a rather large dielectron width, ∼130 eV, so that this resonance may become manifest in the e + e − experiments. On the contrary, the widths of pure D-wave states are very small, Γ ee (n 3 D 1)≤ 2 eV.