# Why do this meson state (consisting with $u,s,d$) are acceptable by nature?

I am new in Particle Physics and try to understand "Quark-Antiquark States:Meson article in Quarks & Leptons by Halzen and Martin(p=46) Why do this meson states are are acceptable by nature $$A=\frac{(u\bar{u} - d\bar{d})}{\sqrt{2}};B=\frac{(u\bar{u} + d\bar{d}-2s\bar{s})}{\sqrt{2}};$$ alongwith $$u\bar{u},u\bar{s},d\bar{u},d\bar{s},s\bar{u},s\bar{d},\frac{(u\bar{u} + d\bar{d}+s\bar{s})}{\sqrt{2}}$$.where it is also a $$q\bar{q}$$ state.How can I find the acceptable (Which also experimentally observable either now or in future?

• I'm afraid the question is founded on a misunderstanding. There is a meson with valence content $(u\bar{u} + d\bar{d})/\sqrt{2}$: the $\omega^0$ (not to be confused with the $\Omega^-$) has that content. Nov 18, 2019 at 6:56
• Okay !Then how many Mason state possible ? Nov 18, 2019 at 8:34
• @baponkar Depends on what you mean by "possible". If you count superpositions of different quark-content eigenstates, then there are uncountably infinitely many. If you only want to count the number of quark-content eigenstates, then start here: en.wikipedia.org/wiki/List_of_mesons Nov 18, 2019 at 13:40
• Thank you for the link @probably_someone Nov 18, 2019 at 17:30

The standard model of particle physics, which has the quarks and leptons in group structures of $$SU(3) \times SU(2) \times U(1)$$ was developed BECAUSE most of the data of particle physics can be fitted with this model, and because it is successful in predicting new data.