Search for s-Channel Single-Top-Quark Production in Events with Missing Energy Plus Jets in p[bar over p] Collisions at s = 1.96 TeV

The first search for single-top-quark production from the exchange of an s -channel virtual W boson using events with an imbalance in the total transverse energy, b -tagged jets, and no identified leptons is presented. Assuming the electroweak production of top quarks of mass 172 . 5 GeV =c 2 in the s channel, a cross section of 1 . 12 þ 0 . 61 − 0 . 57 (stat þ syst) pb with a significance of 1.9 standard deviations is measured. This measurement is combined with the result obtained from events with an imbalance in total transverse momentum, b -tagged jets, and exactly one identified lepton, yielding a cross section of 1 . 36 þ 0 . 37 − 0 . 32 (stat þ syst) pb, with a significance of 4.2 standard deviations.