= Pseudoscalar meson nonet
{title2=$\mathbf8\oplus\mathbf1,\quad J^P=0^-$}
In the <quark model>, the light-flavour triplet and its antiquark conjugate give an octet and a singlet. A colour-singlet pair with orbital angular momentum zero and total spin zero has parity minus one, giving a pseudoscalar nonet. Its six outer weights are charged <pions> and four <kaons>. At the centre the octet contains the neutral pion and octet eta direction; the additional singlet direction gives a third state at the same weight.
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