Selection rules for charged lepton flavor violating processes from residual flavor groups

We systematically investigate the possible phenomenological impact of residual flavor groups in the charged lepton sector. We consider all possible flavor charge assignments for Abelian residual symmetries up to <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:msub><a:mi mathvariant="double-struck">Z</a:mi><a:mn>8</a:mn></a:msub></a:math>. The allowed flavor structures of operators in Standard Model effective field theory (up to dimension six) lead to distinctive and observable patterns of charged lepton flavor violating processes. We illustrate the relevance of such selection rules displaying the current bounds on and the future sensitivities to the new physics scale. These results demonstrate, in particular, the importance and discriminating power of searches for lepton flavor violating <d:math xmlns:d="http://www.w3.org/1998/Math/MathML" display="inline"><d:mi>τ</d:mi></d:math> lepton decays and muonium to antimuonium conversion.