On the B_(c) leptonic decay constant

We give a review and present a comprehensive calculations for the leptonic constant B_{c} of the low-lying pseudoscalar and vector states of B_{c}-meson in the framework of static and QCD-motivated nonrelativistic potential models taking into account the one-loop and two-loop QCD corrections in the short distance coefficient that governs the leptonic constant of B_{c} quarkonium system. Further, we use the scaling relation to predict the leptonic constant of the nS-states of the $\bar{b%}c$ system. Our results are compared with other models to gauge the reliability of the predictions and point out differences.