Mirage mediation of supersymmetry breaking and physics at LHC

标准模型（SM）的超对称扩展（SUSY）被广泛接受为超越标准模型的最有希望的候选物理。然而，超对称在现实世界中是被打破的。超对称性模型的大部分现象学结果实际上取决于超对称性从隐性部门向显性部门断裂的中介机制。传统上，以各种现象学要求为线索，以自下而上的方法研究超对称性断裂的中介机制。最近，超弦的有效超引力理论研究中出现了一类新的调解超对称性破缺的机制，称为“海市蜃楼调解”，引起了人们的广泛关注。在本项目中，我们尝试扩展海市蜃楼中介的概念，并结合LHC的最新实验结果研究海市蜃楼中介的现象学。主要研究结果如下：1。我们分析了有效超引力理论，更多的超弦具有异常U(1)规范对称。根据Stueckelberg质量对规范玻色子质量的贡献与引入以抵消FI项的SM单线态的vev的比值，低能理论中的平坦方向从格林-施瓦茨（GS）模量到SM单线态连续变化。然后在低能理论中出现了SUSY断裂机制的各种组合，包括海市蜃楼介质，它被描述为模量介质和异常介质的结合。在海市蜃楼的作用下，研究了重右手中微子在最小SUSY SM（MSSM）中的轻子风味破坏过程μ→γ。研究发现，除了已知对紫外不敏感的异常介质中的轻子味违反外，在模量和异常介质的混合项中，轻子味违反几乎被右手中微子的阈值修正所抵消。轻子风味违背只存在于模的中介作用中。已知在海市蜃楼中介中，通过在TeV尺度（TeV尺度海市蜃楼中介）周围取海市蜃楼尺度，无需任何微调即可实现比电弱尺度重一级的SUSY尺度。考虑到大型强子对撞机大大提高了超对称性粒子质量的下界，并且大型强子对撞机也报道了最轻的希格斯玻色子几乎粘在MSSM上界的迹象，我们研究了在TeV尺度海市蜃楼调节中放宽微调标准并将超对称性尺度推至10 TeV时的现象学后果。我们计算了最轻的希格斯玻色子质量与超对称性尺度之间的关系。然后我们发现，如果最终发现超对称性粒子超出了lhc的范围，那么tanβ的测量对于计划下一代实验是极其重要的。考虑到LHC引入的上述情况，我们研究了次最小SUSY SM(NMSSM)，其中我们在MSSM上添加了一个SM单重态。我们研究了电弱对称性破缺的结构，并计算了最轻的希格斯玻色子的质量。我们发现，我们可以在不破坏微调的情况下，将有效μ项（higgsino质量）提高到比电弱尺度大得多的程度。这是由于有效μ项和下型希格斯玻色子质量之间的消去。我们还发现，最轻的希格斯玻色子在1个VSUSY尺度下可以同时满足假真空和速子模式的约束，重达125 GeV。在项目中期，大型强子对撞机的第一个结果发表，该结果表明SUSY粒子比项目计划时预期的要重得多，我们将研究的重点从解决暗物质过产问题的模型建立转移到具有自然重SUSY谱的海市蜃楼调解模型的研究上，并在此基础上进行了大型强子对撞机SUSY粒子产生的蒙特卡罗模拟。第二次和第三次的结果仍然是初步的，我们还在继续研究。我们计划将这些研究成果作为该基金的成果发表。少

Supersymmetric(SUSY) extension of the Standard Model(SM) is widely accepted as the most promising candidate for the physics beyond the SM. However, supersymmetry is broken in the real world. Most of the phenomenological consequences of the SUSY models actually depend on the mechanism of mediating SUSY breaking from the hidden sector to the SM sector. Traditionally, the mechanism of mediating SUSY breaking has been investigated in the bottom up approach by taking various phenomenological requirements as a clue to understand it. Recently, a new category of mechanism to mediate SUSY breaking called“mirage mediation"emerged from the study of effective supergravity theory of superstring and has been gathering a lot of attention. In this project, we tried to extend the concept of the mirage mediation and studied the phenomenology of the mirage mediation taking into account the latest experimental results from the LHC. The main results follow :1. We analyzed the effective supergravity theory … More of the superstring having the anomalous U(1) gauge symmetry. Depending on the ratio of the contributions to the gauge boson mass from the Stueckelberg mass and the vev of the SM singlet which is introduced to cancel the FI term, the flat direction in the low energy theory varies continuously from the Green-Schwarz(GS) modulus to the SM singlet. Then various combinations of the SUSY breaking mechanism appear in the low energy theory including the mirage mediation which is described as a combination of the modulus mediation and the anomaly mediation.2. We studied the lepton flavor violating process,μ→eγ, in the minimal SUSY SM(MSSM) with the heavy right-handed neutrino under the mirage mediation. It is found that lepton flavor violation in the mixing terms of the modulus and anomaly mediation is almost cancelled by the threshold correction of the right-handed neutrino, in addition to the lepton flavor violation in the anomaly mediation which is known to be UV insensitive. Then the lepton flavor violation only remains in the modulus mediation contribution.3. It is known that, in mirage mediation, the SUSY scale one order heavier than the electroweak scale can be realized without any fine-tuning by taking the mirage scale around the TeV scale(TeV scale mirage mediation). Considering the fact that the lower bound of the SUSY particle mass is drastically improved by the LHC and indications of the lightest Higgs boson almost sticking to the upper bound in the MSSM are also reported by the LHC, we investigated the phenomenological consequences when we relax the criteria of the fine-tuning in the TeV scale mirage mediation and push the SUSY scale to 10 TeV. We calculated the relation between the lightest Higgs boson mass and the SUSY scale. Then we found that the measurement of tanβis extremely important to plan the next generation experiments if the SUSY particles is eventually found to be out of the reach of the LHC.4. Taking into account the above situation introduced by the LHC, we investigated the Next-to-Minimal SUSY SM(NMSSM) in which we add a SM singlet to the MSSM. We examined the structure of the electroweak symmetry breakingand calculated the mass of the lightest Higgs boson. We found that we can rase the effectiveμterm(the higgsino mass) to considerably heavier than the electroweak scale without deteriorating the fine-tuning. This is because of the cancellation between the effectiveμterm and the down-type Higgs boson mass. We also found that the lightest Higgs boson can be as heavy as 125 GeV for 1 Te VSUSY scale simultaneously satisfying the constraint from the false vacuum and the tachyonic mode.In the middle of the project, the first result from the LHC is published and it suggested that the SUSY particles are much heavier than the expectation when this project is planned, we shifted the emphasis of the study to the study of models with natural heavy SUSY spectrum in mirage mediation from the model building to solve the problem of dark matter over production and the Monte Carlo simulation of SUSY particle production at LHC based on it. The 2nd and 3rd results are still preliminary and we are continuing the studies. We are planning to publish these researches as results of this fund. Less