scholarly journals Supersymmetric gauged $$ \mathrm{U}{(1)}_{L_{\mu }-{L}_{\tau }} $$ model for electron and muon (g − 2) anomaly

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Heerak Banerjee ◽  
Bhaskar Dutta ◽  
Sourov Roy

Abstract Minimal gauged $$ \mathrm{U}{(1)}_{L_{\mu }-{L}_{\tau }} $$ U 1 L μ − L τ models can provide for an additional source for the muon anomalous magnetic moment however it is difficult to accommodate the discrepancy in the electron magnetic moment in tandem. Owing to the relative sign between the discrepancies in these quantities, it seems unlikely that they arise from the same source. We show that a supersymmetric (SUSY) gauged $$ \mathrm{U}{(1)}_{L_{\mu }-{L}_{\tau }} $$ U 1 L μ − L τ model can accommodate both the muon and electron anomalous magnetic moments in a very simple and intuitive scenario, without utilizing lepton flavor violation. The currently allowed parameter space in this kind of a scenario is constrained from the latest LHC and various low energy experimental data,e.g., recent COHERENT data, CCFR, Borexino, BaBaR, supernova etc. These constraints, in conjunction with the requirement to explain both lepton magnetic moments, lead to an upper bound on the first generation slepton mass, a lower bound on the second generation slepton mass and constricts the allowed range for the new gauge boson mass and coupling. The scheme can be probed at the ongoing COHERENT and Coherent CAPTAIN-Mills experiments and at future experiments, e.g., DUNE, BELLE-II etc.

2003 ◽  
Vol 18 (16) ◽  
pp. 2769-2778
Author(s):  
Graham D. Kribs

I explain the theoretical connection between lepton flavor violation and muon g - 2 in supersymmetry1. Given any central value deviation of muon g - 2 from the standard model that is assumed to be due to weak scale supersymmetry, I show that stringent bounds on lepton flavor violating scalar masses can be extracted. These bounds are essentially independent of supersymmetric parameter space. I then briefly compare this indirect handle on supersymmetric lepton flavor violation with direct observation at a future lepton collider operating in the e- e- mode. This is a summary of a talk given at e- e-01: 4th International Workshop on Electron-Electron Interactions at TeV Energies.


2021 ◽  
Vol 81 (9) ◽  
Author(s):  
Tong Li ◽  
Michael A. Schmidt ◽  
Chang-Yuan Yao ◽  
Man Yuan

AbstractAny 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 $$g-2$$ g - 2 precision measurement at Fermilab. We consider the most general SM gauge invariant Lagrangian of $$\Delta L=0$$ Δ L = 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 of the LHC, the MACE experiment, a proposed muonium-antimuonium conversion experiment, and a muon collider. Currently-available LHC data is already able to probe unexplored parameter space via the CLFV process $$pp\rightarrow \gamma ^*/Z^*\rightarrow \ell _1^\pm \ell _1^\pm \ell _2^\mp \ell _2^\mp $$ p p → γ ∗ / Z ∗ → ℓ 1 ± ℓ 1 ± ℓ 2 ∓ ℓ 2 ∓ .


2019 ◽  
Vol 29 (1) ◽  
pp. 87
Author(s):  
Le Tho Hue ◽  
Dinh Phan Khoi ◽  
Hoang Hanh Phuong ◽  
Ha Thanh Hung

Lepton flavor violating (LFV) decays of charged leptons \(\mu\rightarrow e\gamma\)  and SM-like Higgs boson \(h\rightarrow \mu\tau\) are discussed in the framework of the  economical 3-3-1 model  adding three additional singlets neutrinos (E331\(X_R\)). We will show that the appearance of new neutrinos and charged Higgs bosons in this model can result in interesting regions of the parameter space, which satisfy  the recent experimental bound of \(Br(\mu\rightarrow e\gamma)\)  as well as give large \(Br(h\rightarrow \mu\tau)\geq \mathcal{O}(10^{-7})\) . In these regions,  the charged Higgs boson mass lies within the range of \(2-3\) TeV. Our results show that the LFV decays are important channels to distinguish the E331\(X_R\)  and the original economical (E331) models, which predicts suppressed LFV decay rates.


2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Vincenzo Cirigliano ◽  
Kaori Fuyuto ◽  
Christopher Lee ◽  
Emanuele Mereghetti ◽  
Bin Yan

Abstract We present a comprehensive analysis of the potential sensitivity of the Electron-Ion Collider (EIC) to charged lepton flavor violation (CLFV) in the channel ep→τX, within the model-independent framework of the Standard Model Effective Field Theory (SMEFT). We compute the relevant cross sections to leading order in QCD and electroweak corrections and perform simulations of signal and SM background events in various τ decay channels, suggesting simple cuts to enhance the associated estimated efficiencies. To assess the discovery potential of the EIC in τ-e transitions, we study the sensitivity of other probes of this physics across a broad range of energy scales, from pp→eτX at the Large Hadron Collider to decays of B mesons and τ leptons, such as τ→eγ, τ→eℓ+ℓ−, and crucially the hadronic modes τ→eY with Y∈π, K, ππ, Kπ, …. We find that electroweak dipole and four-fermion semi-leptonic operators involving light quarks are already strongly constrained by τ decays, while operators involving the c and b quarks present more promising discovery potential for the EIC. An analysis of three models of leptoquarks confirms the expectations based on the SMEFT results. We also identify future directions needed to maximize the reach of the EIC in CLFV searches: these include an optimization of the τ tagger in hadronic channels, an exploration of background suppression through tagging b and c jets in the final state, and a global fit by turning on all SMEFT couplings, which will likely reveal new discovery windows for the EIC.


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