Narrow Results

A recently proposed strictly phenomenological static quark–antiquark potential belonging to the generality V(r) = -Ar^-α + κr^β + V₀ is tested with heavy quarkonia in the context of the shifted large N-expansion method. This nonrelativistic potential model fits the spin-averaged mass spectra of the , and quarkonia within a few MeV and also the five experimentally known leptonic decay widths of the and vector states. Further, we compute the hyperfine splittings of the bottomonium spectrum as well as the fine and hyperfine splittings of the charmonium spectrum. We give predictions for not yet observed B_c splittings. The model is then used to predict the masses of the remaining quarkonia and the leptonic decay widths of the two pseudoscalar states. Our results are compared with other models to gauge the reliability of the predictions and point out differences.

The fourth Standard Model (SM) family quarks and weak iso-singlet quarks predicted by E₆ GUT are considered. The spin-average of the pseudoscalar η₄(n¹S₀) and vector ψ₄(n³S₁) quarkonium binding masses of the new mesons formed by the fourth Standard Model (SM) family and iso-singlet E₆ with their mixings to ordinary quarks are investigated. Further, the fine and hyperfine mass splittings of the these states are also calculated. We solved the Schrödinger equation with logarithmic and Martin potentials using the shifted large-N expansion technique. Our results are compared with other models to gauge the reliability of the predictions and point out differences.