我们利用T^6/（Z_2 x Z_2 '）上的相交D 6-膜构造了AdS中的超对称Pati-Salam通量真空.所构建的模型有三代MSSM物质加上右手中微子。因为D膜包裹的圈是刚性的，所以伴随表示中没有额外的无质量场，它以开弦模的形式出现。然而，我们发现，这是有问题的Pati-Salam规范对称性打破的标准模型（SM），而保持SM超荷质量。
英文摘要：
We construct supersymmetric Pati-Salam flux vacua in AdS from intersecting D6-branes on T^6/(Z_2 x Z_2'). The models constructed have three generations of MSSM matter plus right-handed neutrinos. Because the cycles wrapped by the D-branes are rigid there are no extra massless fields in the adjoint representation, arising as open-string moduli. However, we find that it is problematic to break the Pati-Salam gauge symmetry to the Standard Model (SM) while keeping the SM hypercharge massless.
We introduce an $N=1$ supergravity model based on the gauged shift symmetry of a single chiral multiplet, which can be identified with the string dilaton or a compactification modulus. The model allows for a tunably small and positive value of the cosmological constant. The gravitino mass parameter and the dilaton Vacuum Expectation Value are separately tunable. In a second part we analyze the quantum consistency of these models. Recent work on anomalies in supergravity theories with Fayet-Iliopoulos terms was extended, such that their results can be interpreted from a field-theoretic point of…
It has been recently argued that an embedding of the SM into a consistent theory of quantum gravity may imply important constraints on the mass of the lightest neutrino and the cosmological constant $Λ_{4}$. The constraints come from imposing the absence of any non-SUSY AdS stable vacua obtained from any consistent compactification of the SM to 3 or 2 dimensions. This condition comes as a corollary of a recent extension of the Weak Gravity Conjecture (WGC) by Ooguri and Vafa. In this paper we study $T^2/Z_N$ compactifications of the SM to two dimensions in which SM Wilson lines are projected o…
Working within the context of the strongly coupled $E_8\times E_8$ heterotic string theory, we analyze the $B-L$ MSSM, a realistic supersymmetric extension of the Standard Model, from both a low-energy phenomenology and high-energy string perspective. From a formal point of view, we examine different constructions of string vacua, which satisfy a series of theoretical and phenomenological constraints. Such vacua configurations are anomaly-free, preserve $N = 1$ SUSY at the compactification scale and yield the correct value for the $SO(10)$ unification scale and gauge coupling in the visible pa…
我们证明了在弦论中真实真空的存在，它的可观测扇区正好具有MSSM的物质含量。这是通过在光滑的卡-丘三重模型上紧化E_8 × E_8杂化超弦，并引入SU（4）规范瞬子和Z_3 × Z_3 Wilson线来实现的。具体地说，可观测扇区是N=1超对称的，具有规范群SU（3）_C x SU（2）_L x U（1）_Y x U（1）_{B-L}，三个夸克和轻子族，每个族都有一个右手中微子，以及一个Higgs-Higgs共轭对。重要的是，在零模谱中没有额外的类矢量对，也没有奇异物质。此外，在可观测扇区中还有6个几何模量和13个规范瞬子模量。可观测扇区的全纯SU（4）向量丛是斜率稳定的。
The quintessence-like potential of vacuum energy can meet the requirement from both quantum gravity and the accelerating expansion of the universe. The anti-de Sitter vacuum in string theory has to be lifted to the meta-stable de Sitter vacuum with positive vacuum energy density to explain the accelerating expansion of the universe. Based on the possible large scale Lorentz violation, we define an effective cosmological constant which depends not only on the bare cosmological constant but also on the Lorentz violation effect. We find the evolution of the effective cosmological constant exhibit…
We perform a detailed conformal field theory analysis of D2-brane instanton effects in four-dimensional type IIA string vacua with intersecting D6-branes. In particular, we explicitly compute instanton induced fermion two-point couplings which play the role of perturbatively forbidden Majorana mass terms for right-handed neutrinos or MSSM mu-terms. These results can readily be extended to higher-dimensional operators. In concrete realizations of such non-perturbative effects, the Euclidean D2-brane has to wrap a rigid, supersymmetric cycle with strong constraints on the zero mode structure. Th…
Supersymmetry Breaking with Fields, Strings and Branes
CPHT, CNRS, École polytechnique, Institut Polytechnique de Paris（巴黎高等理工学院）；APC, UMR 7164-CNRS, Université Paris Cité（巴黎西岱大学）；Scuola Normale Superiore and INFN（比萨高等师范学院和意大利国家核物理研究所）
A Flux-Scaling Scenario for High-Scale Moduli Stabilization in String Theory
研究了Calabi-Yau流形上IIB型定向折叠中基于几何和非几何通量的树级模镇定问题。重点是稳定的非超对称极小值，除了一些无质量的轴子外，所有的模都是固定的。该方案包括纯公理orientifold-odd模。一组真空允许参数控制的模量真空期望值和它们的质量，具有特定的缩放与通量。讨论了类MSSM D 7-膜的不稳定机制和超对称破缺软质量。这个方案为实现弦论中的F项轴子单值暴胀提供了一个完整有效的框架。有人认为，所有的群众接近普朗克和大统一理论的规模，一个是面临着工作的门槛控制所有的质量等级。
We consider string theory vacua with tadpoles for dynamical fields and uncover universal features of the resulting spacetime-dependent solutions. We argue that the solutions can extend only a finite distance $Δ$ away in the spacetime dimensions over which the fields vary, scaling as $Δ^n\sim {\cal T}$ with the strength of the tadpole ${\cal T}$. We show that naive singularities arising at this distance scale are physically replaced by ends of spacetime, related to the cobordism defects of the swampland cobordism conjecture and involving stringy ingredients like orientifold planes and branes, o…
