Full CKM matrix with lattice QCD

Abstract

We show that it is now possible to fully determine the CKM matrix, for the first time, using lattice QCD. |V_{cd}|, |V_{cs}|, |V_{ub}|, |V_{cb}| and |V_{us}| are, respectively, directly determined with our lattice results for form factors of semileptonic D->pi l nu, D->K l nu, B->pi l nu, B->D l nu, and K->pi l nu decays. The error from the quenched approximation is removed by using the MILC unquenched lattice gauge configurations, where the effect of u,d and s quarks is included. The error from the ``chiral'' extrapolation (m_l->m_{ud}) is greatly reduced by using improved staggered quarks. The accuracy is comparable to that of the Particle Data Group averages. In addition, |V_{ud}|, |V_{tb}|, |V_{ts}| and |V_{td}| are determined by using unitarity of the CKM matrix and the experimental result for sin{(2beta)}. In this way, we obtain all 9 CKM matrix elements, where the only theoretical input is lattice QCD. We also obtain all the Wolfenstein parameters, for the first time, using lattice QCD.