New Renormalization Group Equations and the Naturalness Problem

TL;DR

This paper introduces new renormalization group equations for scalar fields that help analyze the unnaturalness problem, revealing a relation between Green functions and propagators that highlights the unnaturalness of scalar fields.

Contribution

It presents a novel set of differential equations for Green functions that extend the traditional renormalization group approach to better understand naturalness issues.

Findings

Identified a relation between four-point Green function and propagator indicating unnaturalness.

Discussed potential low-momentum manifestations of unnaturalness.

Connected new equations to existing RG frameworks.

Abstract

Looking for an observable manifestation of the so-called unnaturalness of scalar fields we introduce a seemingly new set of differential equations for connected Green functions. These equations describe the momentum dependence of the Green functions and are close relatives to the previously known renormalization group equations. Applying the new equations to the theory of scalar field with $\phi^4$ interaction we identify a relation between the four-point Green function and the propagator which expresses the unnaturalness of the scalar field. Possible manifestations of the unnaturalness at low momenta are briefly discussed.