Mass Difference for Charged Quarks from Asymptotically Safe Quantum Gravity.

Astrid Eichhorn,Aaron Held

doi:10.1103/physrevlett.121.151302

Abstract

We propose a scenario to retrodict the top and bottom mass and the Abelian gauge coupling from first principles in a microscopic model including quantum gravity. In our approximation, antiscreening quantum-gravity fluctuations induce an asymptotically safe fixed point for the Abelian hypercharge leading to a uniquely fixed infrared value that is observationally viable for a particular choice of microscopic gravitational parameters. The unequal quantum numbers of the top and bottom quark lead to different fixed-point values for the top and bottom Yukawa couplings under the impact of gauge and gravity fluctuations. This results in a dynamically generated mass difference between the two quarks. To work quantitatively, the preferred ratio of electric charges of bottom and top in our approximation lies in close vicinity to the standard-model value of Q_{b}/Q_{t}=-1/2.

Highlights

We propose a scenario to retrodict the top and bottom mass and the Abelian gauge coupling from first principles in a microscopic model including quantum gravity
The top quark is substantially heavier than all the other quarks, with a pole mass of Mt ≈ 173 GeV [1] significantly larger than the pole mass of the second-heaviest quark, the bottom at Mb ≈ 4.9 GeV [2]
The mechanism follows from microscopic physics in the ultraviolet (UV), where an interplay of quantum gravity and gauge boson dynamics generates asymptotic safety [3,4], i.e., an interacting renormalization group (RG) fixed point at trans

Summary

Introduction

We propose a scenario to retrodict the top and bottom mass and the Abelian gauge coupling from first principles in a microscopic model including quantum gravity. The mechanism follows from microscopic physics in the ultraviolet (UV), where an interplay of quantum gravity and gauge boson dynamics generates asymptotic safety [3,4], i.e., an interacting renormalization group (RG) fixed point at trans-

Results

Conclusion