First measurement of W boson production in association with a single charm quark in p(p)over-bar collisions at √s=1.96 TeV

We present the first measurement of the production cross section of a W boson with a single charm quark (c) in p (p) over bar collisions at root s=1.96 TeV, using soft muon tagging of c jets. In a data sample of similar to 1.8 fb(-1), recorded with the Collider Detector at Fermilab II detector at the Fermilab Tevatron, we select events with W+1 or 2 jets. We use the charge correlation between the W and the muon from the semileptonic decay of a charm hadron to extract the Wc signal. We measure sigma(Wc)(p(Tc)> 20 GeV/c,|eta(c)|< 1.5)xBR(W -> l nu)=9.8 +/- 3.2 pb, in agreement with theoretical expectations.