pi.on
n.Physics （名词）【物理学】 A semistable meson produced either in a neutral form with a mass 2'4 times that of an electron and a mean lifetime of 8.4 × 0-7 second or in a positively charged form with a mass 273 times that of an electron and a mean lifetime of 2.' × 0 -8 second. Also called pi meson See table at subatomic particle π介子：一种半稳定介子，或者以一种质量比电子重2'4倍的中性形式生成，其平均寿命期为8.4×0-7秒；或者以一种质量比电子重273倍的正电极形式生成，其平均寿命期为2.'×0 -8秒 也作 pi meson参见 subatomic particle
来源：Contraction of pi meson pi meson的缩写
