Decoupling of charm beyond leading order

TL;DR

This paper investigates how charm quark effects decouple at low energies using a model with two degenerate charm quarks, confirming that corrections follow the expected quadratic inverse mass behavior.

Contribution

It provides a non-perturbative analysis of charm decoupling, validating the quadratic mass dependence of power corrections in an effective theory approach.

Findings

Power corrections are quadratic in inverse charm mass.

Effective theory reduces to pure gauge theory at leading order.

Ratios of hadronic scales confirm theoretical expectations.

Abstract

We study the effective theory of decoupling of a charm quark at low energies. We do this by simulating a model, QCD with two mass-degenerate charm quarks. At leading order the effective theory is a pure gauge theory. By computing ratios of hadronic scales we have direct access to the power corrections in the effective theory. We show that these corrections follow the expected leading behavior, which is quadratic in the inverse charm quark mass.