Speaker
Description
Experimental precision for measurements of $B$ meson decays will continue to improve over the coming years as Belle II collects more data and the LHC returns to operation after its upgrade period. Independent measurements of $V_{ub}$ will soon be possible using rare $B\to\tau\nu$ decays, for which $B$ meson decay constants $f_B$ are a key input.
We present updates from UKQCD/QCDSF/CSSM on the $SU(3)_{f}$ breaking in $B$ meson decay constants, using weighted averaging methods during the correlator fitting process. The $b$-quarks are generated with an anisotropic clover-improved action, and are tuned to match properties of the physical $B$ and $B^*$ mesons. Configurations are generated with $\overline{m} = \frac{1}{3}(2m_l + m_s)$ kept constant to control symmetry breaking effects. Various sources of systematic uncertainty will be discussed, including those from continuum extrapolations and extrapolations to the physical point.
