Beauty Vector Meson Decay Constants from QCD Sum Rules
  We present the outcomes of a very recent investigation of the decay constants of nonstrange and strange heavy-light beauty vector mesons, with special emphasis on the ratio of any such decay constant to the decay constant of the corresponding pseudoscalar meson, by means of Borel-transformed QCD sum rules. Our results suggest that both these ratios are below unity. 
Wolfgang Lucha, Dmitri Melikhov, Silvano Simula
hep-ph