Reaching the Planck scale with muon lifetime measurements

Physics with a Millimole of Muons

The eventual prospect of muon colliders reaching several TeV encourages us to consider the experimental opportunities presented by very copious stores of muons, approaching $10^{21}$ per year. I summarize and comment upon some highlights of the Fermilab Workshop on Physics at the First Muon Collider and at the Front End of a Muon Collider. Topics include various varieties of $μμ$ colliders, $μp$ colliders, and applications of the intense neutrino beams that can be generated in muon storage rings.

Axion-Like Particles at High Energy Muon Colliders -- A White paper for Snowmass 2021

We study the discovery potential for heavy axion-like particles (ALPs) and the perspectives for determining their coupling properties at a muon collider. Focusing on their couplings to the Standard Model (SM) gauge bosons $γ, Z, W^\pm$, we show that a high-energy muon collider can substantially extend the mass coverage, essentially reaching the kinematic limit of the collider energy. The unique kinematics allow for non-ambiguous determination of the individual coupling strengths. The associated production via $μ^+μ^-$ annihilation and the VBF processes with the tagged outgoing muons can be uti…

离散时空理论可以解释缪子磁矩偏差

Discrete Spacetime Theories Can Explain the Muon Magnetic Moment Discrepancy

本文提出若时空具有基本长度尺度，其对光子传播子的修正可解释缪子反常磁矩偏差，并基于双重狭义相对论计算出该尺度为 $10^{-22}$ m，对应能量约 30 TeV，且有望在下一代对撞机中得到实验验证。

超对称大统一理论中的μ子g-2与轻子味破坏

Muon g-2 and lepton flavor violation in supersymmetric GUTs

本文提出一类超对称大统一模型，可同时解释μ子g-2偏差、给出轻子味破坏信号并符合暗物质限制，为超对称搜寻提供关联基准。

缪子对撞机中修正缪子汤川耦合的多希格斯玻色子信号

Multi Higgs Boson Signals of a Modified Muon Yukawa Coupling at a Muon Collider

研究缪子对撞机中双希格斯和三希格斯产生对缪子汤川耦合修正的敏感性，发现高能下灵敏度可达0.8%，并在二型双希格斯模型中通过增强因子达到10^-6水平。

Minimal models for $g-2$ and dark matter confront asymptotic safety

We use the framework of asymptotic safety above the Planck scale to constrain the parameter space of simple models of new physics that can accommodate the measured value of the anomalous magnetic moment of the muon and the relic density of dark matter. We couple parametrically to the trans-Planckian quantum physics a set of SU(2)$\times$U(1) invariant extensions of the Standard Model, each comprising an inert scalar field and one pair of colorless fermions that communicate to the muons through Yukawa-type interactions. The presence of an interactive UV fixed point in the system of gauge and Yu…

A Combined View of Sterile-Neutrino Constraints from CMB and Neutrino Oscillation Measurements

We perform a comparative analysis of constraints on sterile neutrinos from the Planck experiment and from current and future neutrino oscillation experiments (MINOS, IceCube, SBN). For the first time, we express the Planck constraints on $N_{\rm eff}$ and $m_{\rm eff}^{\rm sterile}$ from the Cosmic Microwave Background in the parameter space used by oscillation experiments using both mass-squared differences and mixing angles. In a model with a single sterile neutrino species and using standard assumptions, we find that the Planck data and the oscillation experiments measuring muon-neutrino di…

The Supersymmetric Flavor Problem

The supersymmetric $SU(3)\times SU(2)\times U(1)$ theory with minimal particle content and general soft supersymmetry breaking terms has 110 physical parameters in its flavor sector: 30 masses, 39 real mixing angles and 41 phases. The absence of an experimental indication for the plethora of new parameters places severe constraints on theories posessing Planck or GUT-mass particles and suggests that theories of flavor conflict with naturalness. We illustrate the problem by studying the processes $μ\rightarrow e + γ$ and $K^0 - \bar{K}^0$ mixing which are very sensitive probes of Planckian phys…

利用单一混合站解开簇射成分能谱的创新方法

Innovative Approaches to Unravel the Shower Components' Energy Spectrum with a Single Hybrid Station

本文提出两种基于单一混合探测器站的方法，分别利用不同探测器响应差异和机器学习重建μ子方向，以提取宇宙线广延大气簇射中电磁成分和μ子成分的能谱。

The High-Energy Frontier of the Intensity Frontier: Closing the Dark Photon, Inelastic Dark Matter, and Muon g-2 Windows

We study hidden sector and long-lived particles at past (CHARM and NuCal), present (NA62 and SeaQuest/DarkQuest), and future (LongQuest) experiments that are at the high-energy frontier of the intensity frontier. We focus on exploring the minimal vector portal and variere-lifetime particles (VLP). VLP models have mostly been devised to explain experimental anomalies while avoiding existing constraints, and we demonstrate that proton fixed-target experiments provide one of the most powerful probes for the sub-GeV to few GeV mass range of the VLP models, using inelastic dark matter (iDM) as an e…

The flavor of quantum gravity

We develop an effective field theory to describe the coupling of non-thermal quantum black holes to particles such as those of the Standard Model. The effective Lagrangian is determined by imposing that the production cross section of a non-thermal quantum black hole be given by the usual geometrical cross section. Having determined the effective Lagrangian, we estimate the contribution of a virtual hole to the anomalous magnetic moment of the muon, $μ\to e γ$ transition and to the electric dipole moment of the neutron. We obtain surprisingly weak bounds on the Planck mass due to a chiral supp…

Testing the $a_μ$ anomaly in the electron sector through a precise measurement of $h/M$

The persistent $a_μ\equiv (g-2)/2$ anomaly in the muon sector could be due to new physics visible in the electron sector through a sub-ppb measurement of the anomalous magnetic moment of the electron $a_e$. Driven by recent results on the electron mass (S. Sturm et al., Nature 506 (2014) 467), we reconsider the sources of uncertainties that limit our knowledge of $a_e$ including current advances in atom interferometry. We demonstrate that it is possible to attain the level of precision needed to test $a_μ$ in the naive scaling hypothesis on a timescale similar to next generation $g-2$ muon exp…