Measurement of the ttbar Production Cross Section in ppbar Collisions at sqrt(s)=1.96 TeV using Soft Electron b- Tagging

We present a measurement of the top quark pair productioncross section in p{bar p} collisions at {radical}s = 1.96 TeV using a data sample corresponding to 1.7 fb{sup -1} of integrated luminosity collected with the Collider Detectorat Fermilab. We reconstruct t{bar t} events in the lepton+jets channel, consisting of e{nu}+jets and {mu}{nu}+jets final states. The dominant background is the production of W bosons in association with multiple jets. To suppress this background, we identify electrons from the semileptonic decayof heavy-flavor jets ('soft electron tags'). From a sample of 2196 candidate events, we obtain 120 tagged events with a background expectation of 51 {+-} 3 events, corresponding to a cross section of {sigma}{sub t{bar t}} = 7.8 {+-} 2.4 (stat) {+-} 1.6 (syst) {+-} 0.5 (lumi) pb. We assume a top-quarkmass of 175 GeV/c{sup 2}. This is the first measurement of the t{bar t} cross section with soft electron tagsin Run II of the Tevatron.