A three-family non-supersymmetric model with U(3)^3 gauge symmetry is analyzed in the context of intersecting D-branes. This is equivalent to the `trinification' model extended by three U(1) factors which survive as global symmetries in the low energy effective model. The Standard Model fermions are accommodated in the three possible bifundamental multiplets represented by strings with endpoints attached on different brane-stacks of this particular setup. Further, a natural Quark-Lepton hierarchy is realized due to the existence of the additional abelian symmetries
Recombination of Intersecting D-Branes and Cosmological Inflation
我们在II型弦论的背景下考虑以任意角度相交的DP膜之间的相互作用。为了宇宙学的目的，我们把理论集中在R^{3，1} x T^6上。将膜之间的距离解释为暴胀子场，膜在紧致空间上最多可以相交两个角度。如果组态是非超对称的，我们将有一个膜间势，它在膜之间的四维相交处提供了一个有效的宇宙学暴胀时期。暴胀的结束发生在膜间距离变得比弦尺度小的时候，在那里一个快子的发展触发了膜的重组。我们研究这种重组由于快子不稳定性，我们发现的可能性，最终的配置再次膜相交的两个角度。从弦模型构建的角度来看，这保留了在暴胀结束后交叉膜模型中存在的有趣特征。这个事实并不存在于仅以一个角度相交的膜模型中。这种重组在其他字符串上下文中也很重要。
Yukawa Coupling Structure in Intersecting D-brane Models
研究了具有相交D-膜的IIA型T^6/（Z_2 x Z_2）定向折叠模型中Yukawa耦合矩阵的结构.在传统的模型中，汤川耦合矩阵是很难实现的，在传统的模型中，生成结构是通过因子化的T^6 = T^2 x T^2 x T^2中D膜的多重相交而出现的。我们研究了新类型的风味结构，汤川耦合是动态生成的，并显示这种类型的模型导致汤川耦合矩阵的非平凡结构，这是现实的。
All the possible three-family ${\cal N}=1$ supersymmetric Pati-Salam models constructed with intersecting D6-branes from Type IIA orientifolds on $T^6/(\mathbb{Z}_2\times \mathbb{Z}_2)$ are recently presented in arXiv: 2112.09632. Taking models with largest wrapping number $5$ and approximate gauge coupling unification at GUT scale as examples, we show string scale gauge coupling unification can be realized through two-loop renormalization group equation running by introducing seven pairs of vector-like particles from ${\cal N}=2$ sector. The number of these introduced vector-like particles ar…
We compute Yukawa couplings in type IIa string theory compactified on a six-torus in the presence of intersecting D6-branes. The six-torus is generated by an SO(12) root lattice. Yukawa couplings are expressed as sums over worldsheet instantons. Our result extends known expressions to a non-factorisable torus. As an aside we also fill in some details for the factorisable torus and non-coprime intersection numbers.
The landscape of string vacua is very large, but generally expected to be finite in size. Enumerating the number and properties of the vacua is an important task for both the landscape and the swampland, in part to gain a deeper understanding of what is possible and "generic". We obtain an exact counting of distinct intersecting brane vacua of type IIA string theory on the $\mathbb{T}^6/\mathbb{Z}_2\times\mathbb{Z}_2$ orientifold. Care is taken to only count gauge-inequivalent brane configurations. Leveraging the recursive nature by which branes may be added together one-by-one, we use dynamic…
Intersecting Branes, SUSY Breaking and the 2TeV Excess at the LHC
弦论中的相交D膜模型可以自然地支持规范对称性为SU（3）_c x SU（2）_L x SU（2）_R x U（1）_{B-L}的标准模型的左右对称扩展的规范和物质内容。考虑到这些模型作为解释ATLAS和CMS在Run-1中看到的2 TeV过量的候选模型，超对称破缺的最小可能尺度由精确的单圈规范耦合统一的要求决定。对于这种膜配置的矢量状，双基本和（反）对称希格斯内容，这在19 TeV左右相当普遍。对于SU（2）_R规范耦合，我们发现0.48<g_R（M_R）<0.6.阈值修正可以潜在地降低超对称破缺的规模。
