The lepton and baryon number difference B-L is conserved in the Standard Model, but the existence of a matter–antimatter asymmetry and non-zero neutrino masses shows that it may be violated in a deeper theory. The simplest such scenarios, e.g. the three seesaw models, often rely on physics at very high scales, beyond the reach of conventional experimental searches. However, the scale of B-L violation is generally lower in radiative neutrino mass models, where loop suppression provides an alternative explanation for the smallness of neutrino masses. I will show how such models can arise within the framework of dimension–7 B-L-violating effective operators, while also leading to distinct experimental signatures in rare meson decays, and present an example of how the early-universe dynamics of the mediating particles can generate a matter–antimatter asymmetry.
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