Mirage mediation of supersymmetry breaking and physics at LHC

大型强子对撞机超对称破缺和物理学的海市蜃楼调解

• 批准号: 21740155
• 负责人: OKUMURA Ken-ichi
• 金额: $ 2.33万
• 依托单位: Kyushu University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Young Scientists (B)
• 财政年份: 2009
• 资助国家: 日本
• 起止时间: 2009 至 2011
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-21740155/
• 关键词: mirage mediation; anomalous U(1); axion; レプトンフレーバーの破れ; 敷居補正; ヒッグス粒子質量; NMSSM; ヒッグス粒子; ミラージュ伝達; ヒッグシーノ; 繰り込み群; 超対称性の破れ; フラーバー物理; 敷居効果; F-理論; LHC; フレーバー物理

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

标准模型的超对称（SUSY）扩展被广泛认为是超越标准模型的最有希望的物理学候选。然而，超对称性在真实的世界中被打破了。超对称性模型的现象学结果实际上取决于超对称性从隐蔽区到对称区的突破机制。传统的超对称性破缺机制研究是以各种唯象要求为线索，从下而上进行的，近年来，在超弦有效超引力理论的研究中，出现了一种新的超对称性破缺机制--“海市蜃楼中介“（mirage mediation），引起了人们的广泛关注。在这个项目中，我们试图扩展海市蜃楼调解的概念，并结合LHC的最新实验结果研究海市蜃楼调解的现象学。主要结果如下：1.我们分析了有效超引力理论 ...更多信息 具有反常U（1）规范对称性的超弦的理论。根据Stueckelberg质量对规范玻色子质量的贡献与SM单线态的vev（用来抵消FI项）之比，低能理论中的平坦方向从格林-施瓦茨（GS）模到SM单线态连续变化。然后在低能理论中出现了各种超对称性破缺机制的组合，其中包括被描述为模量介导和反常介导的组合的海市蜃楼介导.研究了在海市蜃楼介导下，重右手中微子参与的最小超对称模型（MSSM）中轻子味破坏过程μ→eγ.研究发现，除了反常介导中的轻子味破坏外，模和反常介导混合项中的轻子味破坏几乎被右手中微子的阈值修正所抵消.轻子味破坏只存在于模介导贡献中.众所周知，在海市蜃楼调解中，通过采取TeV尺度附近的海市蜃楼尺度（TeV尺度海市蜃楼调解），可以实现比电弱尺度重一阶的SUSY尺度而无需任何微调。考虑到LHC极大地提高了超对称粒子质量的下限，并且LHC也报道了在MSSM中最轻的Higgs玻色子几乎粘在上限上的迹象，我们研究了当我们放宽TeV尺度海市蜃楼调解的微调标准并将超对称尺度推到10 TeV时的唯象后果。计算了最轻的Higgs玻色子质量与超对称性尺度的关系。然后我们发现，如果最终发现超对称粒子超出了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，我们研究了次最小超对称模型（NMSSM），在该模型中，我们添加了一个SM单态。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（希格西诺质量）提高到比电弱标度大得多的程度。这是因为有效μ项和下型希格斯玻色子质量之间的抵消。我们还发现，在同时满足假真空和快子模约束的情况下，最轻的Higgs玻色子在1 Te VSUSY尺度下的质量可以达到125 GeV。在项目中期，LHC发表了第一个结果，这表明SUSY粒子比计划时的预期要重得多，我们的研究重点从解决暗物质过度产生问题的模型建立和在此基础上的LHC超对称粒子产生的Monte Carlo模拟转移到了具有天然重超对称谱的模型在海市蜃楼调解中的研究，第二和第三个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。减

项目成果

Mixed Mediation of Supersymmetry Breaking with Anomalous U(1) Gauge Symmetry

超对称破缺与反常 U(1) 规范对称性的混合中介

• 发表时间: 2011
• 期刊: Journal of High Energy Physics
• 影响因子: 5.4
• 作者: K. Choi;K.S. Jeong;K. Okumura and M. Yamaguchi
• 通讯作者: K. Okumura and M. Yamaguchi