MILC collaboration results for fB, fB0, fD fD3 and their ratios are presented. These results are still preliminary, but the analysis is close to being completed. Sources of systematic error, both within the quenched approximation and from quenching itself, are estimated, We find, for example, fB = 153 ± 10 +36 +13-13 -0 MeV, and fB0/fB = 1.10 ± 0.02 +0.05 +0.03-0.03 -0.02, where the errors are statistical, systematic (within the quenched approximation), and systematic (of quenching), respectively. The extrapolation to the continuum and the chiral extrapolation are the largest sources of error. Present central values are based on linear chiral extrapolations; a shift to quadratic extrapolations would raise fB by ≈20 MeV and make the error within the quenched approximation more symmetric.
ASJC Scopus subject areas
- Atomic and Molecular Physics, and Optics
- Nuclear and High Energy Physics