Answer
The quark combination $s\bar{s}$ can not produce $\Sigma^+$
Work Step by Step
The $\Sigma^+$ has strangeness $-1$
The strange quark $s$ has strangeness $-1$
The strange antiquark $\bar{s}$ has strangeness $+1$
The net strangeness of $s$ and $\bar{s}$ is zero.
Therefore, the quark combination $s\bar{s}$ can not produce $\Sigma^+$
