Isospin violation in mixing and decays of rho- and omega-mesons

Abstract

Influence of the isospin-violating (\rho^0, \omega)-mixing is discussed for any pair of decays of \rho^0, \omega into the same final state. It is demonstrated, in analogy to the CP-violation in neutral kaon decays, that isospin violation can manifest itself in various forms: direct violation in amplitudes and/or violation due to mixing. In addition to the known decays (\rho^0, \omega)\to\pi^+\pi^- and (\rho^0, \omega)\to\pi^0\gamma, the pair of decays to e^+e^- and the whole set of radiative decays with participation of \rho^0, \omega (in initial or final states) are shown to be also useful and perspective for studies. Existing data on these decays agree with the universal character of the mixing parameter and indirectly support enhancement of \rho^0\to\pi^0\gamma in respect to \rho^{\pm}\to\pi^{\pm}\gamma. Future precise measurements will allow to separate different forms of isospin violation and elucidate their mechanisms.