  We report on a search for the supersymmetric partner of the top quark (scalar
top) decaying into a charm quark and a neutralino in p-pbar collisions at
sqrt(s)=1.96 TeV. The data sample, collected by the CDFII detector at the
Fermilab Tevatron, corresponds to an integrated luminosity of 2.6 fb-1.
Candidate events are selected by requiring two or more jets and a large
imbalance in the transverse momentum. To enhance the analysis sensitivity, at
least one of the jets is required to be identified as originating from a charm
quark using an algorithm specifically designed for this analysis. The selected
events are in good agreement with standard model predictions. In the case of
large mass splitting between the scalar top quark and the neutralino we exclude
a scalar top quark mass below 180 GeV at 95% confidence level.
