Is the muon a third family lepton?

Abstract

We propose a new family structure for the Standard Model fermions, where the muon is assigned to the third family, taking the placeholder from the tau lepton. This reassignment, which is a mere choice of convention in the Standard Model, becomes physically meaningful in the presence of new physics assuming a direct link between quarks and leptons. In fact, when quark and leptons are coupled by new interactions, the choice of which lepton is assigned to a particular quark generation brings physical consequences, revealing potentially meaningful patterns in the masses and mixings, while pointing to precise and testable predictions for experiments.

4 pages, 2 figures; updated with the latest RK measurement, main discussion and conclusions unchanged; extended version, 6 pages, 2 figures, matching published version

References in corpus (10)

• Test of lepton universality in beauty-quark decays
• Averages of $b$-hadron, $c$-hadron, and $\tau$-lepton properties as of 2021
• Gauge leptoquark as the origin of B-physics anomalies
• Reading the footprints of the B-meson flavor anomalies
• Low Scale Flavor Gauge Symmetries
• Measurement of the B${}_{\mathrm{S}}^0$ $\to$ ${\mu }^{+}{\mu }^{-}$ decay properties and search for the B${}^0$ $\to$ ${\mu }^{+}{\mu }^{-}$ decay in proton-proton collisions at $\sqrt{s}$ = 13 TeV
• Searching for Leptoquarks at Future Muon Colliders
• Models of Lepton and Quark Masses
• Goldstone Bosons in Effective Theories with Spontaneously Broken Flavour Symmetry
• Search for pair-produced scalar and vector leptoquarks decaying into third-generation quarks and first- or second-generation leptons in pp collisions with the ATLAS detector

Cited by in corpus (1)

• Probing Light Scalars and Vector-like Quarks at the High-Luminosity LHC