We present a search for the pair production of scalar top quarks ((t) over tilde (1)), the lightest supersymmetric partners of the top quarks, in p (p) over bar collisions at a center-of-mass energy of 1.96 TeV, using data corresponding to an integrated luminosity of 7.3 fb(-1) collected with the D0 experiment at the Fermilab Tevatron Collider. Each scalar top quark is assumed to decay into a b quark, a charged lepton, and a scalar neutrino ((nu) over bar).
We investigate final states arising from (t) over tilde (1)(t) over tilde (1) -> b (b) over bar mu tau(nu nu) over tilde and (t) over tilde (1)(t) over tilde (1) -> b (b) over bar tau tau(nu nu) over tilde. With no significant excess of events observed above the background expected from the standard model, we set exclusion limits on this production process in the (m((t) over tilde1), m((nu) over tilde)) plane.