The Muon Anomalous Magnetic Moment in the Excited Fermion Paradigm

TL;DR

This paper investigates how excited fermions could explain the muon's anomalous magnetic moment, using one-loop corrections and effective Lagrangian methods, and derives constraints from experimental data.

Contribution

It provides a detailed analysis of the muon g-2 anomaly within the excited fermion framework, combining theoretical calculations with experimental bounds.

Findings

The muon g-2 anomaly can be explained within a narrow parameter space.

Effective theory constraints are derived from electroweak precision tests.

LHC search data complement the bounds on excited fermion models.

Abstract

Extensions of the Standard Model featuring excited fermions present an interesting framework that motivates the search for exotic particles at the LHC. Additionally, these extensions offer potential explanations for the muon's anomalous magnetic moment and other precision observables, shedding light on the energy scale and key parameters of the new theory. Our analysis focuses on the one-loop radiative correction originating from excited lepton doublet and triplet states using the effective Lagrangian approach. The bounds derived from the $(g-2)_\mu$ anomaly can be complemented with the ones arising from other observables like the electroweak precision observable $\Delta \rho$ and the signals from direct LHC searches to constraint the effective theory. Our results suggest that the $(g-2)_\mu$ anomaly can be addressed within a very narrow region of the effective theory scale. Consequently, this imposes indirect constraints on the parameter space of excited fermions.