The Bearable Compositeness of Leptons

Abstract

Partial compositeness as a theory of flavor in the lepton sector is assessed. We begin presenting the first systematic analysis of neutrino mass generation in this context, and identifying the distinctive mass textures. We then update the bounds from charged lepton flavor and CP violating observables. We put forward a $U(1{)}^3\times CP$ symmetry of the composite sector, in order to allow the new physics to be not far above the TeV scale. This hypothesis effectively suppresses the new contributions to the electron EDM and $\mu \to e\gamma$, by far the most constraining observables, and results in a novel pattern of flavor violation and neutrino masses. The CP violation in the elementary-composite mixing is shown to induce a CKM phase of the correct size, as well as order-one phases in the PMNS matrix. We compare with the alternative possibility of introducing multiple scales of compositeness for leptons, that also allow to evade flavor and CP constraints. Finally, we examine violations of lepton flavor universality in $B$-meson semi-leptonic decays. The neutral-current anomalies can be accommodated, predicting strong correlations among different lepton flavors, with a few channels close to the experimental sensitivity.

arXiv commentReference from ACME collaboration added and bounds from electron EDM updated. Typos and minor errors corrected

References in corpus (36)

• Dimension-Six Terms in the Standard Model Lagrangian
• Bulk Fields and Supersymmetry in a Slice of AdS
• Order of Magnitude Smaller Limit on the Electric Dipole Moment of the Electron
• Neutrino masses and mixings in non-factorizable geometry
• The Strongly-Interacting Light Higgs
• A custodial symmetry for Zbb
• Status of neutrino oscillations 2018: first hint for normal mass ordering and improved CP sensitivity
• Updated fit to three neutrino mixing: exploring the accelerator-reactor complementarity
• Flavor Structure of Warped Extra Dimension Models
• Fermion Masses, Mixings and Proton Decay in a Randall-Sundrum Model
• Detailed calculation of lepton flavor violating muon-electron conversion rate for various nuclei
• Flavor Violating Higgs Decays
• Composite Higgses
• Flavour anomalies after the $R_{K^{\ast }}$ measurement
• Current unknowns in the three neutrino framework
• The Elements of the Neutrino Mass Matrix: Allowed Ranges and Implications of Texture Zeros
• Lepton Flavor Violation in the Standard Model with general Dimension-Six Operators
• Renormalisation-group improved analysis of $\mu \to e$ processes in a systematic effective-field-theory approach
• What is the scale of new physics behind the $B$-flavour anomalies?
• On Partial Compositeness and the CP asymmetry in charm decays
• Violation of lepton flavour universality in composite Higgs models
• Probing the Randall-Sundrum geometric origin of flavor with lepton flavor violation
• Flavor and CP Invariant Composite Higgs Models
• Global fits to b -> s ll data and signs for lepton non-universality
• Addressing the B-physics anomalies in a fundamental Composite Higgs Model
• B-decay anomalies in Pati-Salam SU(4)
• A Natural origin for the LHCb anomalies
• The $\mu \to e\gamma$ decay in a systematic effective field theory approach with dimension 6 operators
• A Common Origin for Neutrino Anarchy and Charged Hierarchies
• Flavor hierarchies from dynamical scales
• Structure of neutrino mass matrix and CP violation
• Neutrino mass matrix: inverted hierarchy and CP violation
• Leptons in Composite MFV
• Lepton Flavour Violation in Composite Higgs Models
• Probing light top partners with CP violation
• A Flavor Sector for the Composite Higgs

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• EFT approach to the electron Electric Dipole Moment at the two-loop level
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• Hypercharged Naturalness
• A vector leptoquark for the B-physics anomalies from a composite GUT
• Natural Seesaw and Leptogenesis from Hybrid of High-Scale Type I and TeV-Scale Inverse
• Holographic models of composite Higgs in the Veneziano limit. Part II. Fermionic sector
• Effective comparison of neutrino-mass models
• Composite Higgs and leptoquarks from a simple group
• SU(6) Gauge-Higgs Grand Unification: Minimal Viable Models and Flavor
• The Techni-Pati-Salam Composite Higgs
• Exploring the Flavor Symmetry Landscape
• Electric Dipole Moments, New Forces and Dark Matter
• Muon collider probes of Majorana neutrino dipole moments and masses
• Conformal Leptogenesis in Composite Higgs Models
• A forgotten fermion: the hypercharge -3/2 doublet, its phenomenology and connections to dark matter
• A composite Froggatt-Nielsen model of flavor
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