A search for the pair production of scalar top quarks, , has been performed in 360 pb−1 of data from collisions at a center-of-mass energy of 1.96 TeV, collected by the DØ detector at the Fermilab Tevatron collider. The decay mode considered is , where is the lightest supersymmetric particle. The topology analyzed therefore consists of a pair of acoplanar heavy-flavor jets with missing transverse energy. The data and standard model expectation are in agreement, and a 95% C.L. exclusion domain in the () plane has been determined, extending the domain excluded by previous experiments.