Charged lepton flavor violating decays and $(g-2{)}_{e_a}$ in an extended standard model with singlet and triplet leptoquarks

Abstract

We study the anomalous magnetic moments of charged leptons and their lepton flavor-violating decays in a Standard Model extension containing one $SU(2{)}_L$singlet and one $SU(2{)}_L$ triplet scalar leptoquark. Our results reveal significant correlations among $\Delta a_{e,\mu }$ and the decay rates of $e_b\to e_a\gamma$, and $h,Z\to e_b{e}_a$. In particular, the branching ratios $\mathrm{Br}(e_b\to e_a\gamma )$ and $\mathrm{Br}(h,Z\to e_b{e}_a)$ exhibit significant correlations. The model cannot simultaneously accommodate sizable values of $|\Delta a_e|=\mathcal{O}(10^{-13})$ and $|\Delta a_{\mu }|=\mathcal{O}(10^{-10})$. For $|\Delta a_{\mu }|=\mathcal{O}(10^{-10})$ and $\mathrm{Br}(\mu \to e\gamma )>10^{-15}$, the decay rates are suppressed to $\mathrm{Br}(\tau \to e\gamma )<\mathcal{O}(10^{-12})$ and $\mathrm{Br}(h\to \tau e)<\mathcal{O}(10^{-6})$, while the remaining ones can reach the forthcoming experimental sensitivities. Conversely, for $|\Delta a_e|=\mathcal{O}(10^{-13})$, one obtains the suppressed decay rates $\mathrm{Br}(\tau \to \mu \gamma )<\mathcal{O}(10^{-11})$ and $\mathrm{Br}(h\to \tau \mu )<\mathcal{O}(10^{-7})$.

27 pages, 9 figures