In physics, bottomness (symbol B′) also called beauty, is a flavour quantum number reflecting the difference between the number of bottom antiquarks (n) and the number of bottom quarks (n) that are present in a particle:
英汉双解词典包含3185865条英汉词条，基本涵盖了全部常用单词的翻译及用法，是英语学习的有利工具。