1

Decay widths for $\rho$ meson is $149 MeV$ while for the $\phi$ meson it is $4MeV$. Why is there such a difference?

I know that the phi meson decays primarily to $K \bar K$ states as the $\pi^+ \pi^- \pi^0$ states are OZI suppressed. The $\rho$ meson decays predominantly to $\pi^+\pi^-$ via strong interaction.

Is OZI suppression the culprit?

user44840
  • 941

1 Answers1

2

Here is the phi mass 1019.445±0.020 MeV/c2. Here is the K mass 493.667±0.013 MeV/c2 , times two 987

1019-987~32 MeV/c2 are left over to be shared as kinetic energy of the two kaons.

It is a matter of phase space. The two pions of the rho are ~280 MeV/c, leaving a lot of phase space to facilitate the decay, i.e. give larger probability because of larger integration scope. enter image description here

In a e+e-scattering experiment: the probability of generating light quarks at a given energy is higher than heavy quarks to make up the phi, because of phase space.

anna v
  • 236,935