  A measurement of the single-top-quark t-channel production cross section in
pp collisions at sqrt(s) = 7 TeV with the CMS detector at the LHC is presented.
Two different and complementary approaches have been followed. The first
approach exploits the distributions of the pseudorapidity of the recoil jet and
reconstructed top-quark mass using background estimates determined from control
samples in data. The second approach is based on multivariate analysis
techniques that probe the compatibility of the candidate events with the
signal. Data have been collected for the muon and electron final states,
corresponding to integrated luminosities of 1.17 and 1.56 inverse femtobarns,
respectively. The single-top-quark production cross section in the t-channel is
measured to be 67.2 +/- 6.1 pb, in agreement with the approximate
next-to-next-to-leading-order standard model prediction. Using the standard
model electroweak couplings, the CKM matrix element abs(V[tb]]) is measured to
be 1.020 +/- 0.046 (meas.) +/- 0.017 (theor.).
