Constraints on $Z'$ solutions to the flavor anomalies with trans-Planckian asymptotic safety

TL;DR

This paper explores how trans-Planckian asymptotic safety constrains $Z'$ models addressing flavor anomalies, predicting kinetic mixing and Yukawa couplings, and analyzing LHC search bounds and future prospects.

Contribution

It introduces a framework embedding $Z'$ models within asymptotic safety, deriving constraints on kinetic mixing and couplings, and analyzing experimental bounds and future search prospects.

Findings

Kinetic mixing constraints from LHC dilepton searches are often unavoidable.

Models with specific charge assignments can evade kinetic mixing constraints.

Future LHC runs can probe the remaining parameter space for heavy vector-like fermions.

Abstract

Motivated by the flavor anomalies in $b \to s$ transitions, we embed minimal models with a $Z'$ gauge boson, vector-like fermions, and a singlet scalar in the framework of trans-Planckian asymptotic safety. The presence of a fixed point in the renormalization group flow of the models' parameters leads to predictions for the $\gamma/Z'$ kinetic mixing, the New Physics Yukawa couplings, and the quartic couplings of the scalar potential. We derive the constraint on the kinetic mixing from the most recent high-mass dilepton resonance searches at the LHC, showing that this bound is often inescapable in this framework, unless the U(1) charges conspire to forbid the radiative generation of kinetic mixing. In the latter case, the parameter space consistent with the flavor anomalies can still be probed in depth by direct LHC searches for heavy vector-like quarks and leptons. We derive the current exclusion bounds and projections for future high-luminosity runs.