Complete one-loop matching of the type-I seesaw model onto the Standard Model effective field theory

In this paper, we accomplish the complete one-loop matching of the type-I seesaw model onto the Standard Model Effective Field Theory (SMEFT), by integrating out three heavy Majorana neutrinos with the functional approach. It turns out that only 31 dimension-six operators (barring flavor structures and Hermitian conjugates) in the Warsaw basis of the SMEFT can be obtained, and most of them appear at the one-loop level. The Wilson coefficients of these 31 dimension-six operators are computed up to O(M-2) with M being the mass scale of heavy Majorana neutrinos. As the effects of heavy Majorana neutrinos are encoded in the Wilson coefficients of these higher-dimensional operators, a complete one-loop matching is useful to explore the low-energy phenomenological consequences of the type-I seesaw model. In addition, the threshold corrections to the couplings in the Standard Model and to the coefficient of the dimension-five operator are also discussed.

Automated summary

In this paper, the complete one-loop matching of the Type-I seesaw model onto the Standard Model Effective Field Theory (SMEFT) is accomplished, resulting in 31 dimension-six operators in the Warsaw basis of the SMEFT. The Wilson coefficients of these operators are computed up to O(M-2), where M is the mass scale of heavy Majorana neutrinos. The effects of heavy Majorana neutrinos on low-energy phenomenology are explored through this one-loop matching, along with discussions on threshold corrections in the Standard Model and the coefficient of the dimension-five operator.