Quantum gravity contributions to the gauge and Yukawa couplings in proper time flow

TL;DR

This paper calculates how quantum gravity affects the running of gauge and Yukawa couplings using the proper-time flow method within the Einstein-Hilbert truncation, analyzing scheme dependence and potential observable impacts.

Contribution

It introduces a novel calculation of quantum gravity contributions to matter coupling beta functions using the Schwinger proper-time flow equation and compares scheme sensitivities.

Findings

Quantified the gravitational correction to matter couplings at the gravity fixed point.

Analyzed the dependence of results on gauge-fixing and regulator choices.

Compared the size of quantum gravity effects with those needed for observable predictions.

Abstract

We derive quantum gravity contributions to the beta functions of the gauge and Yukawa couplings of a matter theory using the Schwinger proper-time flow equation. Working in the Einstein-Hilbert truncation, we investigate the gauge-fixing and regulator dependence of the corresponding renormalization group equations. We quantify the sensitivity of our results on unphysical parameters by evaluating the gravitational correction to the running matter couplings at the interactive fixed point of gravity and we compare our findings with existing determinations in alternative schemes. We finally confront the derived contributions with the typical size they should assume to generate observable low-scale predictions in the Standard Model and in several scenarios of new physics.