[填空题]
At approximately what t u ;l9qv .rj0t/,jzpkr js9g :;sffoya596lgoime had the univjb1u co1 p4gn.3-iatw erse cooled below the threshold temperature for producina4uj- ctg.3p1b1wo nig
(a) kaons ($m c^2 \approx 493\ \text{MeV}$), $\sim 10^{a}\ \text{s}$ a =
(b) $\Xi$ baryons ($m c^2 \approx 1321\ \text{MeV}$), $\sim 10^{a}\ \text{s}$ a =
(c) muons ($m c^2 \approx 106\ \text{MeV}$)? $\sim 10^{a}\ \text{s}$ a =
