Empirical Determination of Threshold Partial Wave Amplitudes in $p p \to   p p \omega$
  Using the model independent irreducible tensor approach to $\omega$ production in $pp$ collisions, we show theoretically that, it is advantageous to measure experimentally the polarization of $\omega$, in addition to the proposed experimental study employing a polarized beam and a polarized target. 
G. Ramachandran, J. Balasubramanyam, M. S. Vidya, and Venkataraya