No abstract

A gluino in the mass range 12-16 GeV combined with a light (2-5.5 GeV) bottom squark, as has been proposed recently to explain an excess of b quark hadroproduction, would affect the momentum-scale dependence ("running") of the strong coupling constant α s in such a way as to raise its value at M Z by about 0.014 ± 0.001. If one combines sources of uncertainty at low (m b ) and high (M Z ) mass scales, one cannot exclude such a possibility. Prospects for improvement in this situation, which include better lattice QCD simulations and better measurements at M Z , are

Using the measured spectrum shape for B→ᐉ, the rate for B ϩ → ϩ 0 , information on the Cabibbo-Kobayashi-Maskawa matrix element ͉V ub ͉, and theoretical inputs from factorization and lattice gauge theory, we obtain an improved estimate of the ''tree'' contribution to B 0 → ϩ Ϫ . We find the branching ratio B(B 0 → ϩ Ϫ )͉ tree ϭ(5.25 Ϫ0.50 ϩ1.67 )ϫ10 Ϫ6 to be compared with the experimental value B(B 0 → ϩ Ϫ )ϭ(4.55Ϯ0.44) ϫ10 Ϫ6 . The fit implies ͉V ub ͉ϭ(3.62Ϯ0.34)ϫ10 Ϫ3 . Implications for tree-penguin interference in B 0 → ϩ Ϫ and for other charmless B decays are discussed.