$T$-odd correlation in polarized neutron decay

$T$-odd correlation $[p_e,p_\nu]\mathbf{\eta}$ appears in lowest order radiative correction to polarized neutron decay width, where $\mathbf{\eta}$ is polarization vector of neutron. It appears as the consequence of final state interaction and cannot be confused with real CP-violating of Standard Model. The value of asymmetry has an order of $10^{-5}$. Final state interaction in the decay of unpolarized neutron caused the appearance of transversal polarization of recoil proton and electron. Explicit expression are given.