Main Question or Discussion Point
Why does the eta prime meson have such a narrow decay width (ie long lifetime) compared to the rho and omega mesons? Is there some conservation rule that supresses its decays?
Indeed it is very interesting so substract the strong decay and to study the anomaly-mediated decay of eta' in the same way than eta and pion.but the phase space is small, limiting the rate.
Generically, when one finds than am allowed strong decay is, er, strongly supressed then the first suspect is OZI rule, which "roughly" asks some of the initial quark content of the decaying particle to survive in the decaying products.Is there some conservation rule that supresses its decays?
To put the numbers in. The reduced decay width, [tex]\tilde \Gamma \equiv \Gamma / m^3[/tex] for the decay of eta' to two photons isIndeed it is very interesting so substract the strong decay and to study the anomaly-mediated decay of eta' in the same way than eta and pion.
Indees that is the way to go I'd wish OZI suppression were more deeply understood, but the limitations of perturbative calculations for SU(3) are an slap in the face.Thanks everyone. I attempted to explain that the eta' lasts about 40 times as long as the omega with a combination of OZI and phase-space arguments.
the stuff on the Z0 is actually unpublished because you should ask for a low energy GUT model to explain it, and such beast plainly does not exist. The stuff on J/Psi could eventually be proved, it amounts to say that all the total sum of allowed decays is "dual" to the decay via the forbidden channel. But nobody tries dualities in electroweak theory, so it will stay in the limbo too. Reduced decay widhts are actually used in some works, but for energies more or less in the same range. I am not sure if one should refine the definition by considering the running of the coupling constants (hard to do, if you only want to use experimental data, theory-independent)A lot of the stuff you guys brought up is really beyond the scope of what we've learned so far.