Measurement of the tt production cross section with an in situ calibration of b-jet identification efficiency

A measurement of the top-quark pair-production cross section in pp collisions at {radical}(s)=1.96 TeV using data corresponding to an integrated luminosity of 1.12 fb{sup -1} collected with the Collider Detector at Fermilab is presented. Decays of top-quark pairs into the final states e{nu}+ jets and {mu}{nu}+ jets are selected, and the cross section and the b-jet identification efficiency are determined using a new measurement technique which requires agreement between the measured cross sections with exactly one and with multiple identified b quarks from the top-quark decays. Assuming a top-quark mass of 175 GeV/c{sup 2}, a cross section of 8.5{+-}0.6(stat){+-}0.7(syst)pb is measured.