Effective field theory offers an appropriate approach to lepton-number violating processes at low energy and to connecting to origin of lepton number violation at high energy scale. In this talk I'll focus on dimension seven operators appearing in standard model effective field theory. I'll discuss their completeness and independence, and their renormalization. I'll explain how to extract anomalous dimensions for a suitably chosen basis of operators constrained by nontrivial flavor relations. As simple illustrations, I'll estimate renormalization effects on neutrinoless double beta decay and unusual proton decay. Reminder: I delivered exactly the same seminar on Mar 22 at TDLI, Jiao-Tong Univ. Please ignore this seminar if you were present there.
