Probing optimal measurements of the electromagnetic dipole moments of the $\tau$ lepton

TL;DR

This paper explores how optimal measurement techniques can improve the detection of electromagnetic dipole moments of the tau lepton at the LHC, highlighting potential benefits and current limitations in experimental sensitivity.

Contribution

It introduces the use of optimal observables for measuring the tau lepton's anomalous magnetic dipole moment in heavy-ion collisions, analyzing their effectiveness with existing data.

Findings

Optimal observables can enhance sensitivity to tau AMDM with larger phase space.

Current data and methods show limited improvement without increased luminosity or helicity measurements.

Future experiments should consider these factors for better tau dipole moment measurements.

Abstract

Precise measurements of the electromagnetic dipole moments of charged leptons are powerful probes of physics beyond the Standard Model of particle physics. It is essential to study avenues for optimizing the measurement strategies for the anomalous magnetic dipole moment (AMDM) and the electric dipole moment (EDM) of the $\tau$-lepton which have recently become accessible at the Large Hadron Collider (LHC). In this work, we study the prospects of employing optimal observables for measuring the AMDM of the $\tau$-lepton in PbPb collisions at the LHC. The performance of optimal observables is investigated in a statistical analysis, assuming an integrated luminosity of 2.0 nb$^{-1}$, approximately corresponding to the amount of data collected during PbPb collisions in Run 2 of the LHC. Improvements of sensitivity to the $\tau$ AMDM with optimal observables are obtained only for a larger phase space than studied so far, more integrated luminosity or including the determination of the helicities of the $\tau$-leptons. Both, chances and limitations, of optimal observables for the $\tau$ AMDM determination will be important to consider in future experiments.