Reexamining the Fritzsch-Stech SO(10) model of quarks and leptons

In a rather predictive model of the quark and lepton mass matrices we discuss restrictions on the quark and lepton mixings implied by two different phenomena: (1) the Mikheyev-Smirnov-Wolfenstein explanation of the solar-neutrino problem and (2) the recent ARGUS measurements of BB-bar mixing and of charmless B decays involving baryons. We conclude that the model allows for neutrino masses and mixings which may account for matter oscillations of either of the two types ν/sub e/ to ν/sub μ/ or ν/sub e/ to ν/sub tau/. In the quark sector the phenomenology of the model is identical to that of the Fritzsch quark matrix. Within our scheme the simplest interpretation of the recent ARGUS results suggests a large value of m/sub t/ around 80 GeV. The model predicts chemical bondU/sub u//sub b/chemical bond to be around 0.0032