A Model of Muon Anomalies

TL;DR

This paper proposes a new gauge symmetry extension of the Standard Model with scalar leptoquarks that explain muon anomalies while remaining consistent with other constraints, and discusses its phenomenological implications.

Contribution

It introduces a novel U(1) gauge symmetry with scalar leptoquarks that address muon anomalies and are compatible with phenomenological constraints and collider searches.

Findings

Explains muon g-2 and B-meson anomalies with new leptoquarks.

Ensures model stability and compatibility up to the Planck scale.

Suppresses charged lepton flavor violation and postpones proton decay.

Abstract

The Standard Model (SM) is augmented with a $\mathrm{U}(1)_{B-3L_\mu} $ gauge symmetry spontaneously broken above the TeV scale when an SM-singlet scalar condenses. Scalar leptoquarks $S_{1(3)} = (\overline{\mathbf{3}},\, \mathbf{1} (\mathbf{3}),\, ^1\!/_3)$ charged under $\mathrm{U}(1)_{B-3L_\mu} $ mediate the intriguing effects observed in muon $(g-2)$, $R_{K^{(*)}}$ and $b \to s \mu^+ \mu^-$, while generically evading all other phenomenological constraints. The fermionic sector is minimally extended with three right-handed neutrinos, and a successful type-I seesaw mechanism is realized. Charged lepton flavor violation is effectively suppressed, and proton decay - a common prediction of leptoquarks - is postponed to the dimension-6 effective Lagrangian. Unavoidable radiative corrections in the Higgs mass and muon Yukawa favor leptoquark masses interesting for collider searches. The parameters of the model are radiatively stable and can be evolved by the renormalization group to the Planck scale without inconsistencies. Alternative lepton-flavored gauge extensions of the SM, under which leptoquarks become muoquarks, are proposed for comparison.