A study of spin alignment of ρ(770)± and w(782) mesons in hadronic Z0 decays

The helicity density matrixelements ρ00 of ρ(770)± and ω(782) mesonsproduced in Z0 decays have been measured using the OPAL detector at LEP. Over the measured mesonenergy range, the values are compatible with 1/3, corresponding to a statistical mix of helicity −1, 0 and +1 states. For the highest accessible scaled energy range 0.3 vector mesons.