AI 中文总结
该研究探讨MEG-II与Mu3e实验通过缪子味违反衰变μ⁺→e⁺χχ̄探测暗物质的潜力，利用六维四费米子算符分析相互作用，可探测TeV量级新物理能标及冻入产生暗物质的参数区域。
AI 中文摘要
我们研究MEG-II和Mu3e等高强度缪子实验通过轻子味违反衰变μ⁺→e⁺χχ̄揭示暗物质（DM）的潜力。我们用六维四费米子算符描述 underlying 相互作用，并系统探索所有允许的洛伦兹结构。结果表明，对米歇尔谱的精确测量可探测DM质量约1 MeV以上时量级为TeV的新物理能标。对于更轻的DM，其信号局限于米歇尔端点附近，MEG-II中的辐射衰变μ⁺→e⁺χχ̄γ可提供互补探测窗口，灵敏度与非辐射道相当，部分区域更强。值得注意的是，当再加热温度低于几十MeV但高于大爆炸核合成（BBN）界限时，MEG-II和Mu3e可探测到通过同一味违反（LFV）相互作用的冻入机制产生观测到的暗物质丰度的参数区域。
英文摘要
We investigate the potential of high-intensity muon experiments such as MEG~II and Mu3e to uncover dark matter (DM) through the lepton-flavor-violating decay $μ^+\to e^+χ\barχ$. We describe the underlying interactions in terms of dimension-six four-fermion operators and systematically explore all allowed Lorentz structures. We show that precision measurements of the Michel spectrum can probe new-physics scales of ${\cal O}({\rm TeV})$ for DM masses above approximately $1~{\rm MeV}$. For lighter DM, whose signal is confined close to the Michel endpoint, the radiative decay $μ^+\to e^+χ\barχγ$ at MEG~II opens a complementary window, with sensitivity comparable to and, in some regions, stronger than that of the non-radiative channel. Remarkably, for reheating temperatures below the tens-of-MeV scale but above the BBN bound, MEG~II and Mu3e can probe regions in which freeze-in through the very same LFV interactions accounts for the observed DM abundance.
Comments43 Pages, 9 Figures
