Can string theory predict the Weinberg angle
Can string theory predict the Weinberg angle
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弦理论可以预测温伯格角吗
DOI：
10.1103/physrevd.76.086006
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发表时间：
2007
影响因子：
5
通讯作者：
A. Wingerter
中科院分区：
文献类型：
--
作者：
S. Raby;A. Wingerter
我们研究了在杂化弦理论的背景下，标准模型中的超电荷赋值是否可以被解释为大统一的暗示。我们的分析是最近对${\mathrm{E}}_{8}\ifmmode\times\else\texttimes\fi{}{\mathrm{E}}_{8}^{\ensuremath{‘}}$杂交链的${\mathbb{Z}}_{6}$-II的微型景观分析的后续。在那个分析中，一个中间的大统一理论(GUT)是寻找类似于MSSM的理论的必要条件。然而，在这个迷你景观中，大约1%的模型类似于MSSM。在本文中，我们取消了这一肠道限制。为此，我们引入了一种通用的方法来计算任何异种奥氏环的{U}(1{)}{Y}，并将我们的结果与肠子产生超电荷的情况进行了比较。令人惊讶的是，在绝大多数的3-2标准模型中，可以定义一个非反常的超电荷方向，其光谱是矢量式的。对于这些模型，我们计算${sin}^{2}{\ensureath{\theta}}_{w}$，以查看它与标准Gut值的一致性程度。我们发现，有12%的人具有${sin}^{2}{\ensureath{\theta}}_{w}=3/8$，而所有其他人的值都较小。最后，89%的${$\mathrm{U}(1{)}_{Y}\ensuremath{\subset}\mathrm{SU}(5)$.}^{2}{\ensureath{\theta}}_{w}=3/8$的模型具有SIN
We investigate whether the hypercharge assignments in the standard model can be interpreted as a hint at grand unification in the context of heterotic string theory. Our analysis is a follow-up to the recent mini-landscape analysis of the ${\mathbb{Z}}_{6}$-II orbifold of the ${\mathrm{E}}_{8}\ifmmode\times\else\texttimes\fi{}{\mathrm{E}}_{8}^{\ensuremath{'}}$ heterotic string. In that analysis, an intermediate grand unified theory (GUT) was a requirement for finding MSSM-like theories. Nevertheless, about 1% of the models in this mini-landscape were MSSM-like. In this paper we remove this GUT restriction. To this end, we introduce a general method to calculate $\mathrm{U}(1{)}_{Y}$ for any heterotic orbifold and compare our findings to the cases where hypercharge arises from a GUT. Surprisingly, in the overwhelming majority of 3-2 standard models, a nonanomalous hypercharge direction can be defined, for which the spectrum is vectorlike. For these models, we calculate ${sin}^{2}{\ensuremath{\theta}}_{w}$ to see how well it agrees with the standard GUT value. We find that 12% have ${sin}^{2}{\ensuremath{\theta}}_{w}=3/8$, while all others have values which are less. Finally, 89% of the models with ${sin}^{2}{\ensuremath{\theta}}_{w}=3/8$ have $\mathrm{U}(1{)}_{Y}\ensuremath{\subset}\mathrm{SU}(5)$.