Lepton flavor violation by two units

Abstract

Charged lepton flavor violation arises in the Standard Model Effective Field Theory at mass dimension six. The operators that induce neutrinoless muon and tauon decays are among the best constrained and are sensitive to new-physics scales up to $10^7$GeV. An entirely different class of lepton-flavor-violating operators violates lepton flavors by two units rather than one and does not lead to such clean signatures. Even the well-known case of muonium--anti-muonium conversion that falls into this category is only sensitive to two out of the three $\Delta L_{\mu }=-\Delta L_e=2$ dimension-six operators. We derive constraints on many of these operators from lepton flavor universality and show how to make further progress with future searches at Belle II and future experiments such as $Z$ factories or muon colliders.

8 pages, matches PLB version

References in corpus (30)

• Dimension-Six Terms in the Standard Model Lagrangian
• Non-Abelian Discrete Symmetries in Particle Physics
• Renormalization Group Evolution of the Standard Model Dimension Six Operators II: Yukawa Dependence
• Tri-Bimaximal Neutrino Mixing, A4 and the Modular Symmetry
• Neutrino-less Double Beta Decay and Particle Physics
• Search for Lepton Flavor Violating Tau Decays into Three Leptons with 719 Million Produced Tau+Tau- Pairs
• Averages of $b$-hadron, $c$-hadron, and $\tau$-lepton properties as of 2021
• New Bounds from Searching for Muonium to Antimuonium Conversion
• Measuring the leading hadronic contribution to the muon g-2 via $\mu e$ scattering
• Lepton flavor violating Z' explanation of the muon anomalous magnetic moment
• Neutrino Tridents at DUNE
• The Standard Model effective field theory at work
• Neutrino Trident Scattering at Near Detectors
• Quark and Lepton Flavor Triality
• Muonium Hyperfine Structure and the Decay ${\mu }^{+}\to e^{+}+{\overline{\nu }}_e+{\nu }_{\mu }$ in Models with Dilepton Gauge Bosons
• Neutrino Trident Production at the Intensity Frontier
• Lepton flavor at the electroweak scale: A complete A4 model
• Interpretation of Lepton Flavor Violation
• Muonium-antimuonium oscillations in effective field theory
• Probing Lepton Flavor Triality with Higgs Boson Decay
• Five-body leptonic decays of muon and tau leptons
• Complementarity of $\mu$TRISTAN and Belle II in searches for charged-lepton flavour violation
• Searches for Lepton Flavor Violation in Tau Decays at Belle II
• Neutrino mass models at $\mu$TRISTAN
• Probing new charged scalars with neutrino trident production
• Physics with Like-Sign Muon Beams
• Lepton-flavour-violating tau decays from triality
• The leptonic di-flavor and di-number violation processes at high energy ${\mu }^{\pm }{\mu }^{\pm }$ colliders
• Four-lepton Z-boson decay constraints on the SMEFT
• Standard Model Decays of Tau into Three Charged Leptons

Cited by in corpus (6)

• Conceptual Design of the Muonium-to-Antimuonium Conversion Experiment (MACE)
• Lepton flavor violation by three units
• Can a Nonstandard Invisible Pair Mimic the Michel Distribution?
• Positron Transport System for Muonium-to-Antimuonium Conversion Experiment
• Lepton flavor violating top quark FCNC processes at the $\mu$TRISTAN
• Lepton flavor violation with tau leptons