  We report a measurement of single top quark production in proton-antiproton
collisions at a center-of-mass energy of \sqrt{s} = 1.96 TeV using a data set
corresponding to 7.5 fb-1 of integrated luminosity collected by the Collider
Detector at Fermilab. We select events consistent with the single top quark
decay process t \to Wb \to l{\nu}b by requiring the presence of an electron or
muon, a large imbalance of transverse momentum indicating the presence of a
neutrino, and two or three jets including at least one originating from a
bottom quark. An artificial neural network is used to discriminate the signal
from backgrounds. We measure a single top quark production cross section of
3.04+0.57-0.53 pb and set a lower limit on the magnitude of the coupling
between the top quark and bottom quark |Vtb| > 0.78 at the 95% credibility
level.
