Loop Effects in Probing Lepton Number Violation

The observation of lepton number violation would provide strong evidence for physics beyond the Standard Model, with neutrinoless double beta decay ($0\nu\beta\beta$) serving as one of the most sensitive experimental probes. In the context of the Standard Model Effective Field Theory (SMEFT), our analysis demonstrates that one-loop corrections can considerably enhance the constraints on new physics scales that are set at tree level for several dimension-7 operators. Through specific ultraviolet (UV) model scenarios, we explore how contributions to $0\nu\beta\beta$ from both dimension-7 and loop-generated dimension-5 SMEFT operators can compete and interplay.