Fixing the parameters of Lattice HQET including 1/m_B terms

Understand

The study of the CKM matrix elements with increasing precision requires a reliable evaluation of hadronic matrix elements of axial and vector currents which can be done with Lattice QCD.

• The tiniest entry, |V_{ub}|, can be estimated independently from B to tau nu and B to pi l nu decays.
• The ALPHA collaboration has undertaken the effort to evaluate non-perturbatively the decay constant f_B and the f^+(q) form factor for q^2 close to q_{max}^2 entering these determinations.
• Since for the b quark m_b >> a^{-1} for available lattice sizes, an effective description of the b quark is necessary.