Tau-Id performance to separate tau leptons with helicity +1 and -1 using $\tau\to a_{1}\nu\to 3\pi^{\pm}\nu$ and $\tau\to\rho\nu\to\pi^{\pm}\pi^0\nu$ decays

The performance of the CMS detector to distinguish between spin states of tau leptons and to perform measurement of tau polarization was studied using $Z\to\tau_\mu\tau_h$, $\tau_h\to a_{1}\nu\to 3\pi^{\pm}\nu$ events with 19.7~fb$^{-1}$ at $\sqrt{s}=$~8~TeV and using $Z\to\tau_\mu\tau_h$, $\tau_h\to\rho\nu\to\pi^{\pm}\pi^0\nu$ events with 2.3~fb$^{-1}$ at $\sqrt{s}=$~13~TeV.