Revisiting lepton flavor violation: $\tau$ and meson decays

Abstract

The minimal type-I seesaw model provides a simple explanation of neutrino flavor oscillations and induces charged lepton flavor violation (cLFV). Despite extensive previous studies, semileptonic cLFV channels remain underexplored. Using updated form factors, decay constants, and oscillation data, we revisit $\tau$ and meson decay channels, performing a systematic comparison across the seesaw parameter space. Surprisingly, we find that decays such as $\tau \to \ell \rho$ can dominate over purely leptonic $\tau$-sector probes, including $\tau \to 3\ell$ and even $\tau \to \ell \gamma$, in certain regions. In contrast, heavy-meson decays remain far below experimental sensitivity. Considering global constraints on the seesaw parameters, we derive branching ratios for the relevant cLFV processes and identify those within potential reach of next-generation experiments.

arXiv commentVersion accepted for publication in JHEP. New section added, conclusion unchanged. 20 pages + appendices (39 pages in total), 9 figures in the main text (+ 4 from appendices)

References in corpus (51)

• Oscillating neutrinos and mu --> e, gamma
• 2020 Global reassessment of the neutrino oscillation picture
• $B\to V{\ell }^{+}{\ell }^{-}$ in the Standard Model from Light-Cone Sum Rules
• Right-Handed Neutrinos at LHC and the Mechanism of Neutrino Mass Generation
• Flavour-Violating Charged Lepton Decays in Seesaw-Type Models
• Low energy effects of neutrino masses
• NuFit-6.0: Updated global analysis of three-flavor neutrino oscillations
• Minimal Flavour Seesaw Models
• A possible symmetry of the $\nu$MSM
• TeV Scale See-Saw Mechanisms of Neutrino Mass Generation, the Majorana Nature of the Heavy Singlet Neutrinos and $\betabeta$-Decay
• STCF Conceptual Design Report: Volume 1 -- Physics & Detector
• Phenomenology of GeV-scale Heavy Neutral Leptons
• Muon conversion to electron in nuclei in type-I seesaw models
• Lepton Flavor and Number Conservation, and Physics Beyond the Standard Model
• Non-decoupling of Heavy Neutrinos and Lepton Flavour Violation
• The mu - e Conversion in Nuclei, mu --> e gamma, mu --> 3e Decays and TeV Scale See-Saw Scenarios of Neutrino Mass Generation
• On the Connection of Leptogenesis with Low Energy CP Violation and LFV Charged Lepton Decays
• Lepton flavor violating Higgs boson decays from massive seesaw neutrinos
• B-meson decay constants: a more complete picture from full lattice QCD
• Low Energy Signatures of the TeV Scale See-Saw Mechanism
• Charged Lepton Flavour Violation from Massive Neutrinos in Z Decays
• Lattice QCD and QCD Sum Rule determination of the decay constants of eta_c, J/psi and hc states
• Constraints on Sterile Neutrinos in the MeV to GeV Mass Range
• Modeling the Pion and Kaon Form Factors in the Timelike Region
• Lepton Flavor Violation in the Standard Model Extended by Heavy Singlet Dirac Neutrinos
• Quasi-Degenerate Neutrino Mass Spectrum, μ-> e + γDecay and Leptogenesis
• Experimental bounds on sterile neutrino mixing angles
• Lepton flavor violation in the Higgs sector and the role of hadronic tau-lepton decays
• Precision tests of fundamental physics with $\eta$ and ${\eta }^{\prime }$ mesons
• FLAG Review 2024
• Charged Lepton Flavor Violation at the EIC
• Masses and decay constants of the $\eta$ and ${\eta }^{\prime }$ mesons from lattice QCD
• The model-discriminating power of lepton flavor violating tau decays
• Lepton Flavor Violation and Dilepton Tails at the LHC
• Light neutrinos from massless texture and below TeV seesaw scale
• Narrow resonances studies with the radiative return method
• SEMILEPTONIC LEPTON-NUMBER/FLAVOUR-VIOLATING tau DECAYS IN MAJORANA NEUTRINO MODELS
• Lepton flavor violating quarkonium decays
• Complete One-loop Matching of the Type-I Seesaw Model onto the Standard Model Effective Field Theory
• Probing Lepton-number/flavour-violation in Semileptonic Tau Decays into Two Mesons
• Lepton flavor-violating transitions in effective field theory and gluonic operators
• Lepton Flavor Violating $\tau$ Decays in TeV Scale Type I See-Saw and Higgs Triplet Models
• Rare Decays of the ${\eta }^{{}^{\prime }}$
• Lepton-flavour violation in hadronic tau decays and $\mu -\tau$ conversion in nuclei
• Long-lived heavy neutral leptons with a displaced shower signature at CMS
• Hadronic Footprint of GeV-Mass Dark Matter
• Indirect constraints on lepton-flavour-violating quarkonium decays
• Comprehensive Analysis of Charged Lepton Flavour Violation in the Symmetry Protected Type-I Seesaw
• Heavy Neutral Leptons -- Advancing into the PeV domain
• Tree-level unitarity constraints on heavy neutral leptons
• The REDTOP experiment: Rare $\eta /{\eta }^{\prime }$ Decays To Probe New Physics