Measurement of B0 - bar B0 mixing using dimuons at D0

During the 1992-1993 collider run at the Fermilab Tevatron, the D0 detector was commissioned and collected 16.1 pb-1 of data which focused on high pT physics such as top searches and electroweak measurements. The B physics accessible in the first run of D0 includes single, dimuon, and J/ψ production cross section measurements over a wide range of rapidity and the measurement of the combined B0 - bar B0 mixing probability χ. Mixing between B0 and its anti-particle can occur in the Standard Model via well-known box diagrams. The mixing parameters xd and xs are of interest because they can be written in terms of parameters of the Standard Model. In particular, xd and xs depend on the CKM matrix elements Vtd and Vts. An accurate measurement of χ can be used to set a lower limit on xs, and thus help constrain elements of the CKM matrix