标题： GUTs——它们有多常见？ 显示英文标题

标题： GUTs -- how common are they?

摘要： 标准模型中的单个费米子族可以很好地融入一个简单的大统一理论规范代数的表示中。 如果大自然中没有实现大统一，这似乎是一个巧合。 我们尝试量化在具有与标准模型相似群结构和费米子内容的理论中，这种巧合出现的频率。 我们发现，与标准模型类似的、一致的费米子表示中有$\mathcal{O}(1/100)$是可统一的，并讨论了结果如何依赖于我们的定义。 这种纯粹的群论分析可以被视为大统一的一个自下而上的指示，概念上类似于自然性论证。 显示英文摘要

摘要： The individual fermion generations of the Standard Model fit neatly into a representation of a simple Grand Unified Theory gauge algebra. If Grand Unification is not realized in nature, this would appear to be a coincidence. We attempt to quantify how frequent this coincidence is among theories with group structure and fermion content similar to the Standard Model. We find that $\mathcal{O}(1/100)$ of consistent fermion representations similar to the Standard Model are unifiable, and discuss how the result depends on our definitions. This purely group-theoretical analysis may be taken as a bottom-up indication for Grand Unification, conceptually similar to a naturalness argument.