| We present the first evidence for electroweak single top quark production using nearly 1 fb-1 of Tevatron Run II data at s = 1.96 TeV. We select single-top-like data events in the lepton+jets decay channel and separate them from backgrounds using the matrix element analysis method. This technique uses leading order matrix elements to compute an event probability for both signal and background hypotheses. Using the expected signal acceptance, background, and observed data we measure the single top quark cross section: spp&d1;→ tb+tqb+X=4.6+1.8-1.5 pb The probability for the background to have fluctuated up to give at least the cross section measured in this analysis is 0.21%, which corresponds to a Gaussian equivalent significance of 2.9sigma. |
