发表机构
Scuola Normale Superiore; INFN; PSI Center for Neutron and Muon Sciences; DAMTP, University of Cambridge; Institut de Física d’Altes Energies (IFAE); Barcelona Institute of Science and Technology (BIST)（高等师范学校; 意大利国家核物理研究所; PSI中子与缪子科学中心; 剑桥大学数学物理系; 高能物理研究所; 巴塞罗那科学技术学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文针对带电轻子味破坏搜寻灵敏度将提升四个数量级的背景，研究强相互作用轻希格斯的部分复合性模型，发现意外对称性可放松约束，使复合性尺度降至几个TeV，为相关实验和对撞机提供目标。
AI 中文摘要
即将开展的实验将大幅提升对带电轻子味破坏的搜寻能力，近期μ→eee衰变和μN→eN转换的速率灵敏度预计将提升四个数量级。我们研究这些测量如何重塑我们对基本相互作用的理解，以及它们对希格斯层级问题的启示。我们考虑具有部分复合性的强相互作用轻希格斯框架。在部分复合性的一般模型中，来自μ→eγ和电子电偶极矩（EDM）的现有约束要求希格斯复合性的尺度高于~O(100) TeV。这些质量尺度超出了大型强子对撞机（LHC）和设想的未来对撞机的直接探测范围，与未来μ→3e和μN→eN搜寻可及的尺度相当或更高。然而，我们表明，强耦合区具有意外U(3)×CP或U(2)×U(1)×CP对称性（该对称性被基本-复合混合打破）的模型，可大幅放松这些约束。在U(3)情形下，这些对称性（1）在领头阶导致汤川耦合与偶极耦合的意外对齐，抑制μ→eγ和电子EDM，使复合性尺度可处于几个TeV的范围；（2）可通过即将开展的μ→eee和μN→eN实验进行探测；（3）为当前和未来对撞机实验提供直接目标。在U(2)×U(1)情形下，μ→eγ和电子EDM仍是重要约束，而即将开展的μ→eee、μN→eN及味破坏τ衰变搜寻则提供互补探测手段。我们讨论这些意外对称性如何在红外区域产生，同时与紫外区域味层级的动力学生成兼容。
英文摘要
Upcoming experiments are set to dramatically improve the search for charged lepton flavor violation, with the sensitivity to the rates of $μ\to eee$ decay and $μN\to eN$ conversion expected to improve by four orders of magnitude in the near future. We study how these measurements reshape our understanding of fundamental interactions and their implications for the Higgs hierarchy problem. We consider the framework of Strongly Interacting Light Higgs with partial compositeness. In generic models of partial compositeness, the existing constraints from $μ\to eγ$ and the electric dipole moment (EDM) of the electron require the scale of Higgs compositeness to be above $\sim\mathcal{O}(100)$ TeV. These mass scales lie beyond the direct reach of the LHC and envisioned future colliders and are comparable to, or higher than, those accessible to future $μ\to3e$ and $μN\to eN$ searches. We show, however, that models where the strongly coupled sector has an accidental $U(3)\times\mathrm{CP}$ or $U(2)\times U(1) \times\mathrm{CP}$ symmetry, broken by the elementary--composite mixings, can substantially relax these constraints. In the $U(3)$ case, these symmetries (1) lead to an accidental alignment of the Yukawa and dipole couplings at leading order, suppressing $μ\to eγ$ and the electron EDM, allowing the compositeness scale to lie in the few-TeV range; (2) are probed by the upcoming $μ\to eee$ and $μN\to eN$ experiments; and (3) provide a direct target for current and future collider experiments. In the $U(2)\times U(1)$ case, $μ\to eγ$ and the electron EDM remain important constraints, while upcoming searches for $μ\to eee$, $μN\to eN$ and flavor-violating $τ$ decays provide complementary probes. We discuss how these accidental symmetries can arise in the infrared compatibly with the dynamical generation of flavor hierarchies in the ultraviolet.
Comments48 pages, 10 figures
