Integrating out new fermions at one loop

Authors

Andrei Angelescu, University of Nebraska - Lincoln
Peisi Huang, University of Nebraska - LincolnFollow

Date of this Version

1-11-2021

Citation

JHEP01 (2021) 049. https://doi.org/10.1007/JHEP01(2021)049

Comments

Open access

Abstract

We present the fermionic universal one-loop effective action obtained by integrating out heavy vector-like fermions at one loop using functional techniques. Even though previous approaches are able to handle integrating out heavy fermions with non-chiral interactions, i.e. vanishing γ⁵ interaction terms, the computations proceed in a tedious manner that obscures a physical interpretation. We show how directly tackling the fermionic functional determinant not only allows for a much simpler and transparent computation, but is also able to account for chiral interaction terms in a simple, algorithmic way. Finally, we apply the obtained results to integrate out at one loop the vector-like fermions appearing in a toy model and in a fermionic model that exhibits strong cosmological phase transitions.