2023 Impact factor 4.2
Particles and Fields

Eur. Phys. J. C 22, 503-520 (2001)
DOI: 10.1007/s100520100806

Isospin symmetry breaking within the HLS Model: A full ( $\rho$, $\omega$, $\phi$) mixing scheme

M. Benayoun1, 2 and H.B. O'Connell3

1  CERN, Laboratoire Européen pour la Recherche Nucléaire, 1211 Genève 23, Switzerland
2  LPNHE des Universités Paris VI et VII-IN2P3, Paris, France
3  Stanford Linear Accelerator Center, Stanford University, Stanford, CA 94309, USA

(Received: 18 July 2001 / Revised version: 4 October 2001 / Published online: 21 November 2001 - © Springer-Verlag / Società Italiana di Fisica 2001 )

We study the way isospin symmetry violation can be generated within the Hidden Local Symmetry (HLS) Model. We show that isospin symmetry breaking effects on pseudoscalar mesons naturally induces correspondingly effects within the physics of vector mesons, through kaon loops. In this way, one recovers all features traditionally expected from $\rho-\omega$ mixing and one finds support for the Orsay phase modelling of the $e^+e^- \rightarrow
\pi^+ \pi^-$ amplitude. We then examine an effective procedure which generates mixing in the whole $\rho$, $\omega$, $\phi$ sector of the HLS Model. The corresponding model allows us to account for all two body decays of light mesons accessible to the HLS model in modulus and phase, leaving aside the $\rho \rightarrow \pi \pi$ and $K^* \rightarrow K \pi$ modes only, which raise a specific problem. Comparison with experimental data is performed and covers modulus and phase information; this represents 26 physics quantities successfully described with very good fit quality within a constrained model which accounts for SU(3) breaking, nonet symmetry breaking in the pseudoscalar sector and, now, isospin symmetry breaking.

© Società Italiana di Fisica, Springer-Verlag 2001