Parity Mixing Effects inτ−θDecay

The recent results on nonconservation of parity in decay processes involving neutrinos do not provide an unambiguous solution of the $\tau -\theta$ puzzle. In fact the $2\pi$ and $3\pi$ decay modes of $\theta$ and $\tau$ involve no neutrinos, whereas the Lee-Yang two-component neutrino theory attributes the nonconservation of parity to special properties of the neutrino. However, even if the $\tau$ and $\theta$ are different particles with opposite parities, the neutrino decay modes ($\mu , \nu$), ($e, \pi , \nu$), and ($\mu , \pi , \nu$), which presumably violate parity conservation, will cause mixing of the two particles $\tau$ and $\theta$—in the sense that the states with definite lifetimes will be certain linear combinations, $K_1$ and $K_2$, of $\tau$ and $\theta$. Both $K_1$ and $K_2$ will then decay into both $2\pi$ and $3\pi$ as well as the neutrino modes, but with different lifetimes. An explanation of the apparent equality of lifetimes of $\tau$ and $\theta$ may be that under present experimental conditions only the long-lived component $K_2$ is observed. If this is the case, interference effects between the $K_1$ and $K_2$ components should be found in experiments performed at shorter times. Conversely, absence of such effects would constitute strong evidence that $\tau$ and $\theta$ are identical.