Possible methods for the determination of the $P$-parity of the $\Theta^+$-pentaquark in NN-collisions

Abstract

We present two possibilities to determine the P-parity of the pentaquark $\Theta^+$, in a model independent way, via the measurement of polarization observables in $p+p\to \Theta^+ +\Sigma^+$, or $n+p\to \Theta^+ +\Lambda^0$, in the near threshold region. Besides the measurement of the spin correlation coefficient, $A_{xx}=A_{yy}$, (in collisions of transversally polarized nucleons), the coefficient $D_{xx}$ of polarization transfer from the initial proton to the final $ \Sigma^+(\Lambda^0)$ hyperon is also unambiguously related to the $\Theta^+$ parity.