We investigate whether the Minimal Supersymmetric Standard Model with the scalar masses of the third generation distinct from the first two, in order to be able to accommodate the muon anomalous magnetic moment, is consistent with the latest results from LHCb, direct collider bounds from the ATLAS and CMS experiments. In particular, we show that this class of models allows for satisfying both the constraints from the muon $(g-2)_μ$ experiment and various bounds from the LHC. In addition, such models can also explain the observed dark matter relic density.
Flavor and CP violations from sleptons at the muon collider
超对称理论通常有新的味道和CP破坏源的夸克和slepton质量矩阵。它们将有助于轻子味道破坏过程，如$μ\to e γ$，它可以在μ子对撞机前端的强μ子源下远低于电流约束进行探测。此外，如果slepton可以在μ子对撞机上产生，那么在它们的产生和衰变过程中就会发生味道破坏，这使得我们可以直接探测味道混合结构。$μ^+ e^-$和$e^+ μ^-$事件数目之间的不对称性将是超对称风味混合中CP破坏的标志。
We propose a SUSY scenario to explain the current electron and muon $g-2$ discrepancies without introducing lepton flavor mixings. Threshold corrections to the Yukawa couplings can enhance the electron $g-2$ and flip the sign of the SUSY contributions. The mechanism predicts a flavor-dependent slepton mass spectrum. We show that it is compatible with the Higgs mediation scenario.
Lepton Flavor Violation: From Muon Decays to Muon Colliders
University of California Santa Cruz（加州大学圣克鲁兹分校）；University of Oregon（俄勒冈大学）；University of Chicago（芝加哥大学）；Harvard University（哈佛大学）；University of California, Berkeley（加州大学伯克利分校）；Lawrence Berkeley National Laboratory（劳伦斯伯克利国家实验室）；University of Pittsburgh（匹兹堡大学）；Cornell University（康奈尔大学）；Institute for Advanced Study（普林斯顿高等研究院）；New York University（纽约大学）
A muon collider would be a powerful probe of flavor violation in new physics. There is a strong complementary case for collider measurements and precision low-energy probes of lepton flavor violation (as well as CP violation). We illustrate this by studying the collider reach in a supersymmetric scenario with flavor-violating slepton mixing. We find that the collider could discover sleptons and measure the slepton and neutralino masses with high precision, enabling event reconstruction that could cleanly separate flavor-violating new physics signals from Standard Model backgrounds. The discove…
Any observation of charged lepton flavor violation (CLFV) implies the existence of new physics beyond the SM in charged lepton sector. CLFV interactions may also contribute to the muon magnetic moment and explain the discrepancy between the SM prediction and the recent muon $g-2$ precision measurement at Fermilab. We consider the most general SM gauge invariant Lagrangian of $ΔL=0$ bileptons with CLFV couplings and investigate the interplay of low-energy precision experiments and colliders in light of the muon magnetic moment anomaly. We go beyond previous work by demonstrating the sensitivity…
We consider a model with multi-charged particles including vector-like fermions and a charged scalar under a local $U(1)_{μ- τ}$ symmetry. We search for allowed parameter region explaining muon anomalous magnetic moment (muon $g-2$) and $b \to s \ell^+ \ell^-$ anomalies, satisfying constraints from the lepton flavor violations, $Z$ boson decays, meson anti-meson mixing and collider experiments. Carrying out numerical analysis, we explore the typical size of the muon $g-2$ and Wilson coefficients to explain $b \to s \ell^+ \ell^-$ anomalies in our model when all other experimental constraints a…
For the purpose of minimizing the number of sample model evaluations, we propose and study algorithms that utilize (sequential) versions of likelihood-to-evidence ratio neural estimation.We apply our algorithms to a supersymmetric interpretation of the anomalous muon magnetic dipole moment in the context of a phenomenological minimal supersymmetric extension of the standard model, and recover non-trivial models in an experimentally-constrained theory space. Finally we summarize further potential possible uses of these algorithms in future studies.
We analyze the flavor violating muon decay $μ\rightarrow eχ$, where $χ$ is a massive gauge boson, with emphasis in the regime where $χ$ is ultralight. We first study this process from an effective field theory standpoint in terms of form factors. We then present two explicit models where $μ\rightarrow eχ$ is generated at tree level and at the one-loop level. We also comment on the prospects of observing the process $μ\rightarrow eχ$ in view of the current limits on $μ\rightarrow 3e$ from the SINDRUM collaboration.
We present an economical model where an $S^{}_1$ leptoquark and an anomaly-free $U(1)^{}_X$ gauge symmetry with $X = B^{}_3-2L^{}_μ/3-L^{}_τ/3$ are introduced, to account for the muon anomalous magnetic moment $a^{}_μ\equiv (g^{}_μ-2)$ and flavor puzzles including $R^{}_{K^{(\ast)_{}}}$ and $R^{}_{D^{(\ast)_{}}}$ anomalies together with quark and lepton flavor mixing. The $Z^\prime_{}$ gauge boson associated with the $U(1)^{}_X$ symmetry is responsible for the $R^{}_{K^{(\ast)_{}}}$ anomaly. Meanwhile, the specific flavor mixing patterns of quarks and leptons can be generated after the spontan…
The recent experimental status, including the confirmation of the muon $g-2$ anomaly at Fermilab, indicates a Beyond Standard Model (BSM) satisfying the following properties: 1) it enhances the $g-2$ 2) suppresses flavor violations, such as $μ\to e γ$, 3) suppresses CP violations, such as the electron electric dipole moment (EDM). In this letter, I show that if the masses of heavy leptons are generated radiatively, the eigenbasis of the mass matrix and higher dimensional photon operators can be automatically aligned. As a result, the muon $g-2$ is enhanced but the EDM of the electron and $μ\to…
The stringent experimental bound on $μ\rightarrow e γ$ is compatible with a simultaneous and sizable new physics contribution to the electron and muon anomalous magnetic moments $(g-2)_\ell$ ($\ell=e,\,μ$), only if we assume a non-trivial flavor structure of the dipole operator coefficients. We propose a mechanism in which the realization of the $(g-2)_\ell$ correction is manifestly related to the mass generation through a flavor symmetry. A radiative flavon correction to the fermion mass gives a contribution to the anomalous magnetic moment. In this framework, we introduce a chiral enhancemen…
Higgs-mediated muon-electron conversion process in supersymmetric seesaw model
在超对称跷跷板模型中研究了Higgs交换图对轻子味破坏的μ子-电子转换过程的影响。这种贡献对于tan β的大值和中性重希格斯玻色子质量的小值是显著的，在这种情况下，B（mu N -> e N）/ B（mu -> e γ）的分支比的比率增强。我们还表明，转换分支比的靶原子的依赖性提供了希格斯交换图的大小上的信息。
Patterns of flavor signals in supersymmetric models
研究了四种超对称模型中夸克和轻子的味信号，即最小超引力模型、含右手中微子的最小超对称标准模型、含右手中微子的SU（5）超对称大统一理论和含U（2）味对称的最小超对称标准模型.考虑到最近在Tevatron上观测到的B_s-B_s条混合的约束，我们计算了B_d和B_s衰变中的b -> s（d）跃迁观测值。我们还计算了右手中微子模型的轻子味破坏过程μ-> e γ，τ-> μ γ和τ-> e γ。我们调查的可能性，以区分风味结构的超对称性破缺部门使用的各种口味的信号，预计将在实验中，如MEG，LHCb和未来的超级B工厂测量的模式。
Flavor-specific scalar bosons exist in various Standard Model extensions and couple to a single generation of fermions via a global flavor symmetry breaking mechanism. Given this strategy, we propose a MeV flavor-specific scalar model in dimension-$5$ operator series, which explains the muon g-2 anomaly and proton radius puzzle by coupling with the muon and down-quark at the same time. The framework is consistent with the null result of high-intensity searches. Specifically, the supernova constraints for muon couplings become weakened by including the contribution of down-quark interaction. Th…
Flavor violating processes in the lepton sector have highly suppressed branching ratios in the standard model. Thus, observation of lepton flavor violation (LFV) constitutes a clear indication of physics beyond the standard model (BSM). We review new physics searches in the processes that violate the conservation of lepton (muon) flavor by two units with muonia and muonium--antimuonium oscillations.
The discrepancy between the measured value and the Standard Model prediction of the muon anomalous magnetic moment is one of the most important issues in the particle physics. It is known that introducing a mediator boson X with the $μτ$ lepton flavor violating (LFV) couplings is one good solution to explain the discrepancy, due to the $τ$ mass enhancement in the one-loop correction. In this paper, we study the signal of this model, i.e. the same-sign leptons, in the Belle II experiment, assuming the flavor-diagonal couplings are suppressed. We show that the Belle II experiment is highly sensi…
Lepton-flavor violating decays of neutral Higgs to muon and tauon in supersymmetric economical 3-3-1 model
在超对称经济3 - 3 - 1（SUSYE331）模型中研究了Higgs粒子到μ子-τ子的轻子味破坏（LFV）衰变.在sleptons {mu，tau}中存在风味混合和大的v/v '值时，Br（H--> tau ^+ mu ^-）/Br（H--> tau ^+ tau ^-）的比率可以达到不可忽略的值O（10 ^{-3}），如在许多已知的SUSY模型中那样。我们预测，对于标准模型的希格斯玻色子，大型强子对撞机可能会检测到它衰变为μ子和τ子。我们还研究了左右LFV修正值之间的不对称性，证明了LFV效应主要由左FLV项控制，在小的数值极限下，左FLV项比右LFV项大O（10^3）倍。|μ_ρ|/m_SUSY。Higgs介导的影响的衰变τ-->亩的贡献进行了讨论。
Muon anomalous magnetic moment, lepton flavor violation, and flavor changing neutral current processes in SUSY GUT with right-handed neutrino
受大气和太阳中微子异常的大混合角解的启发，在SU（5）超对称大统一理论框架下分析了中微子味变中性流过程和轻子味破坏过程以及μ子反常磁矩.为了解释夸克和轻子的真实质量关系，我们考虑了GUT尺度以上的高维算子的影响。结果表明，超对称（SUSY）效应对$K^0-\bar{K}^0$混合CP破坏参数、$ε_K$、$μ\to e γ$分支比和μ子反常磁矩的贡献在很宽的参数空间范围内变大.我们还研究了这些量之间的相关性。在目前的实验范围内的$\text{B}(μ\to e γ)$，大超对称性的贡献是可能的，无论是在μ子异常磁矩或在$ε_K$。在前一种情况下，最近在BNL E821实验上测量的μ子异常磁矩的有利值可以被容纳。在后一种情况下，Kobayashi-Maskawa相的允许区域可能与标准模型（SM）中的预测不同，因此$B\to J/ψK_S$模式和$Δm_{B_s}$模式的CP不对称性的测量可以将这种情况与SM区分开来。当中微子参数与Mikheyev-Smirnov-Wolfenstein小混合角解一致时，$τ\to μγ$分支比可以接近当前实验上界，并且混合诱导的辐射B衰变CP不对称性可以增强.
The present work investigates the possibility that both dark matter and the anomalous magnetic moment of the muon may be explained within the context of the inverse seesaw extended Next-to-Minimal Supersymmetric Standard Model (ISS-NMSSM). In ISS-NMSSM, the newly introduced Higgs-neutrino Yukawa coupling $Y_ν$ provides additional Higgsino-sneutrino loop contribution to $(g-2)_μ$. If the deviation between the experimental observations and the Standard Model predictions of the anomalous muon magnetic moment is confirmed by the further experimental and theoretical studies, it can be explained nat…
Neutrino Mass, Muon Anomalous Magnetic Moment, and Lepton Flavor Nonconservation
如果中微子质量的产生机制既能解释新观测到的μ子反常磁矩，又能解释目前轻子味不守恒的实验界，那么中微子质量矩阵应该是几乎简并的，并且在未来的对撞机上可以观察到潜在的物理现象。我们在两个具体的例子中说明了这一论断，并表明，$Γ(μ\to e γ)/m_μ^5$，$Γ(τ\to e γ)/m_τ^5$，和$Γ(τ\to μγ) /m_τ^5$的比例分别为$(Δm^2)_{sol}^2/2$，$(Δm^2)_{sol}^2 /2$，和$(Δm^2)_{atm}^2$，其中的$Δm^2$参数是太阳和大气中微子振荡和双峰混合已被假定。
Clockwork models can explain the flavor hierarchies in the Standard Model quark and lepton spectrum. We construct supersymmetric versions of such flavor clockwork models. The zero modes of the clockwork are identified with the fermions and sfermions of the Minimal Supersymmetric Standard Model. In addition to generating a hierarchical fermion spectrum, the clockwork also predicts a specific flavor structure for the soft SUSY breaking sfermion masses. We find sizeable flavor mixing among first and second generation squarks. Constraints from Kaon oscillations require the masses of either squarks…
