Search for the decay D to mu mu at CDF Run II

We report on a search for the flavor-changing neutral current decay D0 to mu+mu- in pp-bar collisions at sqrt = 1.96 TeV using 330 pb-1 of data collected by the CDF experiment at the Fermilab Tevatron Collider. A displaced-track trigger selects long-lived D0 candidates in the D0 to mu+mu- search channel. The kinematically similar D0 to pi+pi- channel is used for normalization, and the Cabbibo-favored D0 to K-pi+ channel is used to optimize the selection criteria in an unbiased manner. This analysis is an extension of a previous search using 65 pb-1 of data, when a limit was set on the branching fraction, B(D0 to mu+mu-) less than 2.5 x 10(-6) at the 90 percent confidence level.