We report on analyses of tau lepton decays $tau^- to eta K^- u_{tau}$ and $tau^- to eta pi^- u_{tau}$, with $eta to pi^+ pi^- pi^0$, using 470 fb$^{-1}$ of data from the Babar experiment at PEP-II, collected at center-of-mass energies at and near t
he $Upsilon(4S)$ resonance. We measure the branching fraction for the $tau^- to eta K^- u_{tau}$ decay mode, $Br(tau^- to eta K^- u_{tau}) = (1.42pm0.11text{(stat)}pm0.07text{(syst)})times10^{-4}$, and report a 95% confidence level upper limit for the second-class current process $tau^- to eta pi^- u_{tau}$, $Br(tau^- to eta pi^- u_{tau}) < 9.9times10^{-5}$.
We report an analysis of tau- decaying into omega.pi-.nu_tau with omega -> pi+pi-pi0 using a data sample containing nearly 320 million tau pairs collected with the BABAR detector at the PEP-II B-Factory. We find no evidence for second-class currents
and we set an upper limit of 0.69% at 90% confidence level for the fraction of second-class currents in this decay mode.
