Abstract :
A new phenomenological approach is suggested to determine the strangeness contents of light-flavour isoscalars. This approach is based on phenomenological laws of hadron production related to the spin, isospin, strangeness content and mass of the particles. The “effective” numbers of s and s̄ quarks in the isoscalar partners i1 and i2 are given by the nonstrange–strange mixing angle ϕ :k(i1)=2sin2ϕ and k(i2)=2cos2ϕ. From the total production rates per hadronic Z decay of all light-flavour hadrons measured so far at LEP the values for k are found to be: k(η)≡2−k(η′)=0.91±0.12, k(φ)≡2−k(ω)=1.94±0.09, k(f′2)≡2−k(f2)=1.84±0.21 and k(f0)=0.09±0.13. Our results on the η–η′, ω–φ and f2–f′2 isoscalar mixing are consistent with the present experimental evidence. Quite remarkably, our value for k(η) corresponds to the singlet–octet mixing angle θP=−12.4°±3.5°. The obtained strangeness content of the f0(980) scalar/isoscalar is not consistent with the values supported by different model studies. However, taking the f0(980) in our analysis with the mass of the bare state (K-matrix pole) f0bare(720±100), the mixing angle is found to be: |ϕSbare|=73°±7°±24°, in good agreement with the prediction of the K-matrix analysis.
