Masses and decay constants of B_q mesons in the QCD string approach

Abstract

The relativistic string Hamiltonian is used to calculate the masses and decay constants of $B_q$ mesons: they appear to be expressed through onlythree fundamental values: the string tension $\sigma$, ${\alpha }_s$, and the quark pole masses. The values $f_B=186$ MeV, $f_{B_s}=222$ MeV are calculated while $f_{B_c}$ depends on the $c$-quark pole mass used, namely $f_{B_c}=440(424)$ MeV for $m_c=1.40(1.35)$ GeV. For the $1P$ states we predict the spin-averaged masses: $\bar{M}(B_J)=5730$ MeV and $\bar{M}(B_{sJ})=5830$ MeV which are in good agreement with the recent data of the D0 and CDF Collaborations, at the same time owning to the string correction being by $\sim 50$ MeV smaller than in other calculations.

Comments: 9 pages, ICHEP 2006