  The top quark pair production cross section is measured in dilepton events
with one electron or muon, and one hadronically decaying tau lepton from the
decay t anti-t to (l nu(l)) (tau nu(tau)) b anti-b, where l can be either an
electron or a muon. The data sample corresponds to an integrated luminosity of
2.0 inverse femtobarns for the electron channel and 2.2 inverse femtobarns for
the muon channel, collected by the CMS detector at the LHC. This is the first
measurement of the t anti-t cross section explicitly including tau leptons in
proton-proton collisions at sqrt(s) = 7 TeV. The measured value sigma(t anti-t)
= 143 +/- 14 (stat.) +/- 22 (syst.) +/- 3 (lumi.) pb is consistent with the
standard model predictions.
