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Abstract We present the first detailed phenomenological analysis of a radiative Majorana neutrino mass model constructed from opening up a ∆L = 2 mass-dimension-11 effective operator constructed out of standard model fields. While three such operators are generated, only one dominates neutrino mass generation, namely O 47 = L C ¯ L Q C ¯ L Q ¯ Q C HH , $$ {O}_{47}=\overline{L^C}L\overline{Q^C}L\overline{Q}{Q}^C HH, $$ where L denotes lepton doublet, Q quark doublet and H Higgs doublet. The under- lying renormalisable theory contains the scalars S 1 ∼ 3 ¯ 1 1 / 3 $$ {S}_1\sim \left(\overline{3},1,1/3\right) $$ coupling as a diquark, S 3 ∼ 3 ¯ 3 1 / 3 $$ {S}_3\sim \left(\overline{3},3,1/3\right) $$ coupling as a leptoquark, and Φ3 ∼ (3, 3, 2/3), which has no Yukawa couplings but does couple to S 1 and S 3 in addition to the gauge fields. Neutrino masses and mixings are generated at two-loop order. A feature of this model that is different from many other radiative models is the lack of proportionality to any quark and charged- lepton masses of the neutrino mass matrix. One consequence is that the scale of new physics can be as high as 107 TeV, despite the operator having a high mass dimension. This raises the prospect that ∆L = 2 effective operators at even higher mass dimensions may, when opened up, produce phenomenologically-viable radiative neutrino mass models. The parameter space of the model is explored through benchmark slices that are subject to experimental constraints from charged lepton flavour-violating decays, rare meson de- cays and neutral-meson mixing. The acceptable parameter space can accommodate the anomalies in R K (∗) and the anomalous magnetic moment of the muon. |
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