kaon

詳細解釋：

ka.on

n.Abbr. K（名詞）縮寫 K
An unstable meson produced either in an electrically charged form with a mass 9'' times that of an electron or in a neutral form with a mass 974 times that of an electron as a result of a high-energy particle collision.Also called K-meson See table at subatomic particle
K介子：一種不穩定的介子，由於高能粒子碰撞，在帶電結構中產生，其質量為一個電子的9''倍；或在不帶電的結構中產生，其質量為一個電子的974倍也作 K-meson參見 subatomic particle

來源：
ka [pronunciation of the letter] k
ka [字母] K的發音
-on
-on