Mesons withbquarks: Spectroscopy and electromagnetic properties

Abstract

We treat the recently discovered $\Upsilon$ particle at 9.41 GeV as evidence for a fifth quark flavor, the $b$ quark. An SU(5) mass formula is then used to predict the masses of other $b\overline{b}$ states. The masses of the $b$-quark analogs of the $D$ and $F$ mesons ($B_N, B_s, B_c$, etc.) are predicted, as are their production cross sections in $e^{+}{e}^{-}$ annihilation. At best, the $B_N^{*}$ ${\overline{B}}_N^{*}$ combination will be seen at 12 GeV with a cross section of ∼0.3 nb. As with the charm domain, the $B_N^{*}-B_N$ mass difference is about one pion mass. The predicted electromagnetic mass splitting is only about 2 MeV for $B_N^{+}-B_N^0$, so that the strong-interaction decay widths of the $B^{*}\text{'}\mathrm{s}$ will be of the same order as the electromagnetic decay widths.