A study of spin alignment of $\rho(770)^{\pm}$ and $\omega(782)$ mesons in hadronic Z$^0$ decays

The OPAL Collaboration:     G. Abbiendi - et al.

doi:doi:10.1007/s100520050003

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2022 Impact factor 4.4

Particles and Fields

Eur. Phys. J. C 16, 61-70
DOI 10.1007/s100520000388

A study of spin alignment of $\rho(770)^{\pm}$
and $\omega(782)$ mesons in hadronic Z⁰ decays

The OPAL Collaboration

G. Abbiendi² - et al.

²Dipartimento di Fisica dell' Università di Bologna and INFN, 40126 Bologna, Italy

Received: 14 June 1999 / Published online: 8 May 2000 - © Springer-Verlag 2000

Abstract
The helicity density matrix elements $\rho_{00}$ of $\rho(770)^{\pm}$ and $\omega(782)$ mesons produced in Z⁰ decays have been measured using the OPAL detector at LEP. Over the measured meson energy 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 < x_E < 0.6, the measured $\rho_{00}$ values of the $\rho^{\pm}$ and the $\omega$ are 0.373 $\pm$ 0.052 and 0.142 $\pm$ 0.114, respectively. These results are compared to measurements of other vector mesons.