B_d mixing and prospects for B_s mixing at D0
  Measurement of the B_s oscillation frequency via B_s mixing analyses provides a powerful constraint on the CKM matrix elements. The study of B_d oscillations is an important step towards B_s mixing and a preliminary measurement of Delta m_d has been made with ~250 pb^-1 of data collected with the upgraded Run II D0 detector. Different flavor tagging algorithms have been developed and are being optimized for use on a large set of B_s mesons that have been reconstructed in different semileptonic decay modes. 
Tulika Bose (Columbia University)