Speaker
Description
The general consequences of $T$ invariance for the direct
and inverse binary reactions $a + b \rightarrow c + d$ ,
$c + d \rightarrow a + b$ with spin-1/2 particles $a$, $b$
and unpolarized particles $c$, $d$ are analyzed.
Using the formalism of helicity amplitudes, the theoretical study of polarization
effects in the reaction $p + \,^{3}{He}
\rightarrow \pi^{+} + \,^{4}{He}$ and in the inverse process
$\pi^{+} + \,^{4}{He} \rightarrow p + \,^{3}{He}$ is performed. It is shown
that in the reaction $\pi^{+} + \,^{4}{He}
\rightarrow p + \,^{3}{He}$ the spins of the final proton and $^{3}{He}$ nucleus are strongly correlated. A structural
expression through helicity amplitudes, corresponding to arbitrary emission angles, is obtained for the correlation tensor. It is established that in the reaction $\pi^{+} + \,^{4}{He} \rightarrow p + \,^{3}{He}$ one of the "classical" incoherence inequalities of the Bell type for
diagonal components of the correlation tensor is necessarily violated and, thus, the spin correlations in the final system $(p,\,^{3}{He})$ have the strongly pronounced quantum character.
