Muon Anomalous Magnetic Dipole Moment Research Articles

Neutrino mass model and dark matter with Y = 0 inert triplet scalar

We study a one-loop induced neutrino mass model with an inert isospin triplet scalar field of Y=0 and heavier isospin doublet vector-like leptons and singlet Majorana right-handed fermions. In addition to the neutrino mass matrix, we explain sizable scale of muon anomalous magnetic dipole moment 10−9 by introducing a singly-charged boson S±. We show numerical analysis of neutrino oscillation, lepton flavor violations, Z boson decays, and demonstrate our allowed regions in cases of normal and inverted hierarchies. We find the sizable scale of muon anomalous magnetic dipole moment for both cases. Then, we move on to the discussion of dark matter candidates to satisfy the relic density where we have two candidates; fermionic dark matter and bosonic one. And, we classify four cases fermionic dark matter with normal and inverted hierarchies, bosonic one with normal and inverted hierarchies and search for each of the allowed points in the model.

Study on muon MDM and lepton EDM in BLMSSM via the mass insertion approximation

In the framework of the MSSM extension with local gauged baryon and lepton numbers (BLMSSM), we calculate the muon anomalous magnetic dipole moment (MDM) and lepton (e, μ, τ) electric dipole moment (EDM), and discuss how the muon MDM and lepton EDM depend on the parameters within the mass insertion approximation. Among many parameters, , g L , m L and μ H are more sensitive parameters for . Considering the experimental limitations, our best numerical result of is around 2.5 × 10−9, which can well compensate the departure between the experiment data and standard model (SM) prediction. The CP violating phases in BLMSSM are more than those in the MSSM, including new parameters and θ L . They can give large contributions, which play an important role in exploring the source of CP violation and probing new physics beyond SM.

New dark matter candidate in the B-L\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$B-L$$\\end{document} symmetric SSM

The B-L symmetric SUSY model (B-LSSM) introduces a new Z′\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$Z'$$\\end{document} gauge boson and two singlet scalars, which indicates there are more neutralinos in the B-LSSM comparing with the minimal SUSY extension of standard model (MSSM). These new neutralinos provide more dark matter (DM) candidates in the B-LSSM, we find that the super partner of the new scalar singlet can serve as the lightest supersymmetric particle (LSP) and be considered as a DM candidate. The properties of this new DM candidate are analyzed in this work. Taking into account the experimental constraints on Higgs boson mass, B meson rare decays and muon anomalous magnetic dipole moment, the numerical results are obtained and presented. The properties of new DM candidate in the B-LSSM satisfy the observed relic density Ωh2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\Omega h^2$$\\end{document} and comply with the latest upper bounds on σSIχ10-n\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\sigma _\ extrm{SI}^{\\chi _1^0-n}$$\\end{document}, and its mass is expected to greater than 80GeV\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$80\\;\ extrm{GeV}$$\\end{document} approximately.

Muon anomalous magnetic dipole moment in a low scale type I see-saw model

Recent experimental results on muon anomalous magnetic dipole moment have shown a 4.2σ tension with the SM prediction, which has blown a fresh wind into the elementary particle physics community. The problem is believed to be explained only by physics beyond the standard model. Current work considers the anomalous moment in a scenario of models with mirror symmetry and type I see-saw mechanism at low energy scale of electroweak interactions. After a brief introduction to the model, a detailed numerical analysis of muon anomalous phenomenology will be carefully performed. Analysis results show that the model is not successful in explaining the muon moment problem, however the contributions of channels involving neutral Higgs scalars, including both the light and heavy ones, might provide sizable corrections to the discrepancy.

Muon anomalous magnetic dipole moment in the μ νSSM * *Supported by the National Natural Science Foundation of China (11705045, 11535002, 12075074), the Natural Science Foundation for Distinguished Young Scholars of Hebei Province (A2022201017), the Natural Science Foundation of Guangxi Autonomous Region (2022GXNSFDA035068), the youth top-notch talent support program of the Hebei Province, and Midwest Universities Comprehensive Strength Promotion project

Recently, the Muon g-2 experiment at Fermilab measured the muon anomalous magnetic dipole moment (MDM), , and reported that the new experimental average increases the difference between the experiment and the standard model (SM) prediction to 4.2σ. In this work, we reanalyze the muon anomalous MDM at the two-loop level in the μ from the ν Supersymmetric Standard Model ( SSM) combined with the updated experimental average. The SSM can explain the current difference between the experimental measurement and the SM theoretical prediction for the muon anomalous MDM, constrained by the 125 GeV Higgs boson mass and decays, the rare decay , and so on. We also investigate the anomalous MDM of the electron and tau lepton, and , at the two-loop level in the SSM. In addition, the decaying of the 125 GeV Higgs boson into a pair of charged leptons in the SSM is analyzed.

Negative muon count for the Fermilab Muon Campus accelerator

The Fermilab Muon g-2 experiment aims to measure the muon anomalous magnetic dipole moment to a precision of 0.14 ppm. Recent results with positive muons confirm a discrepancy between its experimental and theoretical value. However, running the experiment with negative muons is equally as important as it will provide an additional data point for the value of the muon anomaly. This work will examine the feasibility of achieving such a measurement by estimating the rates of negative muons arriving at the experiment as well as discuss important accelerator-based modifications needed in order to achieve this goal. We found that the rate of negative muons arriving at the experiment is roughly 60% that of positives. Although highly polarized, the delivered negative muons are mostly free from unwanted backgrounds contrary to their countersign muons.

General kinetic mixing in gauged U(1)Lμ−Lτ model for muon g−2 and dark matter

The gauged $U(1{)}_{{L}_{\ensuremath{\mu}}\ensuremath{-}{L}_{\ensuremath{\tau}}}$ extension of the Standard Model is a very simple framework that can alleviate the tension in muon anomalous magnetic dipole moment, reinforced by the recent Fermilab measurement. We explore experimental probes of the $(g\ensuremath{-}2{)}_{\ensuremath{\mu}}$ target with a general treatment of kinetic mixing between the ${Z}^{\ensuremath{'}}$ gauge boson and the photon. The physical value of the kinetic mixing depends on a free parameter of the model and energy scale of a process. We find neutrino constraints on the $(g\ensuremath{-}2{)}_{\ensuremath{\mu}}$ target including Borexino, coherent elastic neutrino-nucleus scattering, and white dwarfs are sensitive to this freedom and can be lifted if the kinetic mixing lies in proximity of zero at low momentum transfer. As a further step, we explore ${L}_{\ensuremath{\mu}}\ensuremath{-}{L}_{\ensuremath{\tau}}$ charged dark matter with a thermal origin and show that the same scenario of kinetic mixing can relax existing direct detection constraints and predict novel recoil energy dependence in the upcoming searches. Future joint effort of neutrino and dark matter experiments and precision spectral measurement will be the key to test such a theory.

Muon g−2 in a two-Higgs-doublet model with a type-II seesaw mechanism

We study the two-Higgs-doublet model with type-II seesaw mechanism. In view of constraints from the Higgs data, we consider the aligned two-Higgs-doublet scheme and its effects on muon anomalous magnetic dipole moment, $a_{\mu}$, including both one-loop and two-loop Barr-Zee type diagrams. Thanks to a sizable trilinear scalar coupling, the Barr-Zee type diagrams mediated by the Higgs triplet fields have a dominant effect on $a_{\mu}$. In particular, unlike the usual two-Higgs-doublet models that require exotic Higgs bosons light in mass, the masses of the corresponding particles in the model are of ${\cal O}(100)$~GeV. The doubly-charged Higgs boson presents a different decay pattern from the usual Higgs triplet model and thus calls for a new collider search strategy, such as multi-$\tau$ searches at the LHC.

Large (g−2)μ and signals of decays eb→eaγ in a 3−3−1 model with inverse seesaw neutrinos

We show that under current experimental bound of the decays $e_a\rightarrow e_b\gamma$, the recent experimental data of the muon anomalous magnetic dipole moment $(g-2)_{\mu}$ can be explained in the framework of the 3-3-1 model with right handed neutrinos. In addition, all of these branching ratios can reach closely the recent experimental upper bounds.

Explanations for anomalies of muon anomalous magnetic dipole moment, b→sμμ¯ , and radiative neutrino masses in a leptoquark model

We propose a leptoquark model simultaneously to explain anomalies of muon anomalous magnetic dipole moment and $b\to s \mu\bar\mu$ in light of experimental reports very recently. Here, we satisfy several stringent constraints such as $\mu\to e\gamma$ and meson mixings. In addition, we find these leptoquarks also play an role in generating tiny neutrino masses at one-loop level without introducing any additional symmetries. We have numerical analysis and show how degrees our parameter space is restricted.

Muon (g \u2212 2) in the B-LSSM

The difference between the updated experimental result on the muon anomalous magnetic dipole moment and the corresponding theoretical prediction of the standard model on that is about 4.2 standard deviations. In this work, we calculate the muon anomalous MDM at the two-loop level in the supersymmetric B − L extension of the standard model. Considering the experimental constraints on the lightest Higgs boson mass, Higgs boson decay modes h → γγ, WW, ZZ, boverline{b} , tau overline{tau} , B rare decay overline{B} → Xsγ, and the transition magnetic moments of Majorana neutrinos, we analyze the theoretical predictions of the muon anomalous magnetic dipole moment in the B − L supersymmetric model. The numerical analyses indicate that the tension between the experimental measurement and the standard model prediction is remedied in the B − L supersymmetric model.

Radiative seesaw mechanism for charged leptons

We discuss a mechanism where charged lepton masses are derived from one-loop diagrams mediated by particles in a dark sector including a dark matter candidate. We focus on a scenario where the muon and electron masses are generated at one loop with new $\mathcal{O}(1)$ Yukawa couplings. The measured muon anomalous magnetic dipole moment, $(g\ensuremath{-}2{)}_{\ensuremath{\mu}}$, can be explained in this framework. As an important prediction, the muon and electron Yukawa couplings can deviate significantly from their standard model predictions, and such deviations can be tested at High-Luminosity LHC and future ${e}^{+}{e}^{\ensuremath{-}}$ colliders.

Flavor-changing decay h \u2192 \u03c4 \u03bc at super hadron colliders

We study the flavor-changing decay h → τ μ with τ = τ− +τ+ and μ = μ− +μ+ of a Higgs boson at future hadron colliders, namely: a) High Luminosity Large Hadron Collider, b) High Energy Large Hadron Collider and c) Future hadron-hadron Circular Collider. The theoretical framework adopted is the Two-Higgs-Doublet Model type III. The free model parameters involved in the calculation are constrained through Higgs boson data, Lepton Flavor Violating processes and the muon anomalous magnetic dipole moment; later they are used to analyze the branching ratio of the decay h → τ μ and to evaluate the gg → h production cross section. We find that at the Large Hadron Collider is not possible to claim for evidence of the decay h → τ μ achieving a signal significance about of 1.46σ by considering its final integrated luminosity, 300 fb−1. More promising results arise at the High Luminosity Large Hadron Collider in which a prediction of 4.6σ when an integrated luminosity of 3 ab−1 and tan β = 8 are achieved. Meanwhile, at the High Energy Large Hadron Collider (Future hadron-hadron Circular Collider) a potential discovery could be claimed with a signal significance around 5.04σ (5.43σ) for an integrated luminosity of 3 ab−1 and tan β = 8 (5 ab−1 and tan β = 4).

Higgs boson decay h \u2192 Z\u03b3 and muon magnetic dipole moment in the \u03bc\u03bdSSM

To solve the μ problem and generate three tiny neutrino masses in the MSSM, the μ from ν Supersymmetric Standard Model (μνSSM) introduces three singlet right- handed neutrino superfields, which lead to the mixing of the Higgs doublets with the sneutrinos. The mixing affects the lightest Higgs boson mass and the Higgs couplings. The present observed 95% CL upper limit on signal strength of the 125 GeV Higgs boson decay h → Zγ is 6.6, which still is plenty of space to prove the existence of new physics. In this work, we investigate the signal strength of the 125 GeV Higgs boson decay channel h → Zγ in the μνSSM. Besides, we consider the two-loop electroweak corrections of muon anomalous magnetic dipole moment (MDM) in the model, which also make important contributions compared with one-loop electroweak corrections.

Lepton specific two-Higgs-doublet model based on a U(1)X gauge symmetry with dark matter

We discuss a two Higgs doublet model with extra $U(1)_X$ gauge symmetry where lepton specific (type-X) structure for Yukawa interactions is realized by charge assignment of fields under the $U(1)_X$. Extra charged leptons are introduced to cancel gauge anomaly associated with extra gauge symmetry. In addition, we introduce scalar fields as dark matter candidates to which we assign $Z_2$ odd parity for guaranteeing stability of them. We then analyze phenomenology of the model such as scalar potential, muon anomalous magnetic dipole moment, collider physics associated with $Z'$ boson from $U(1)_X$, and dark matter physics. Carrying out numerical analysis we search for phenomenologically viable parameter region.

A simple model for explaining muon-related anomalies and dark matter

We propose a model to explain several muon-related experimental anomalies and the abundance of dark matter. We introduce a vector-like exotic lepton that form an iso-doublet and three right-handed Majorana fermions as an iso-singlet. A real/complex scalar field is added as a dark matter candidate. We impose a global [Formula: see text] symmetry under which fields associated with the SM muon are charged. To stabilize the dark matter, we impose a [Formula: see text] (or [Formula: see text]) symmetry under which the exotic lepton doublet and the real (or complex) scalar field are charged. We find that the model can simultaneously explain the muon anomalous magnetic dipole moment and the dark matter relic density in no conflict with any lepton flavor-violating/conserving observables, with some details depending upon whether the scalar field is real or complex. Besides, we extend the framework to the quark sector in a way similar to the lepton sector, and find that the recent anomalies associated with the [Formula: see text] transition can also be accommodated while satisfying constraints such as the [Formula: see text] decays and neutral meson mixings.

A variant two-Higgs doublet model with a new Abelian gauge symmetry

We consider a two-Higgs doublet model extended with a broken Abelian gauge symmetry under which all Standard Model (SM) quarks, fourth generation fermions and a new SM-singlet scalar boson are charged. Such a setup is shown to be able to accommodate the muon anomalous magnetic dipole moment while being consistent with existing constraints of flavor-violating decays of charged leptons and Z boson. The new scalar boson offers a suitable dark matter candidate that interacts with the SM particles via the Higgs portal and the Z′ boson associated with the new gauge symmetry. The dark matter direct detection bound is found to impose a strong constraint on the new gauge coupling.

A novel approach to finely tuned supersymmetric standard models: The case of the non-universal Higgs mass model

Discarding the prejudice about fine tuning, we propose a novel and efficient approach to identify relevant regions of fundamental parameter space in supersymmetric models with some amount of fine tuning. The essential idea is the mapping of experimental constraints at a low energy scale, rather than the parameter sets, to those of the fundamental parameter space. Applying this method to the non-universal Higgs masses model, we identify a new interesting superparticle mass pattern where some of the first two generation squarks are light whilst the stops are kept heavy as 6TeV. Furthermore, as another application of this method, we show that the discrepancy of the muon anomalous magnetic dipole moment can be filled by a supersymmetric contribution within the 1 {\sigma} level of the experimental and theoretical errors, which was overlooked by the previous studies due to the required terrible fine tuning.

Loop suppressed light fermion masses with U(1)R gauge symmetry

We propose a model with two Higgs doublet where quark and charged-lepton masses in the first and second families are induced at one-loop level, and neutrino masses are induced at the two-loop level. In our model we introduce an extra $U(1)_R$ gauge symmetry that plays a crucial role in achieving desired terms in no conflict with anomaly cancellation. We show the mechanism to generate fermion masses, the resultant mass matrices and Yukawa interactions in mass eigenstates, and discuss several interesting phenomenologies such as muon anomalous magnetic dipole moment and dark matter candidate that are arisen from this model.

125 GeV Higgs decay with lepton flavor violation in the μνSSM**Supported by Major Project of NNSFC (11535002) and NNSFC (11275036, 11647120), the Open Project Program of State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, China (Y5KF131CJ1), the Natural Science Foundation of Hebei province (A2013201277, A2016201010, A2016201069), Hebei Key Lab of Optic-Electronic Information and Materials,

Recently, the CMS and ATLAS collaborations have reported direct searches for the 125 GeV Higgs decay with lepton flavor violation, h → μτ. In this work, we analyze the signal of the lepton flavour violating (LFV) Higgs decay h → μτ in the μ from ν Supersymmetric Standard Model (μνSSM) with slepton flavor mixing. Simultaneously, we consider the constraints from the LFV decay τ → μγ, the muon anomalous magnetic dipole moment and the lightest Higgs mass around 125 GeV.