A study of the measurement of the $\tau$ lepton anomalous magnetic moment in high energy lead-lead collisions at LHC

TL;DR

This paper proposes a new method using ultra-peripheral lead-lead collisions at LHC to measure the tau lepton's anomalous magnetic moment with improved sensitivity, leveraging photon-photon interactions and advanced analysis techniques.

Contribution

It introduces a novel experimental approach combining effective Lagrangian modeling and multivariate analysis to enhance the measurement sensitivity of the tau lepton's magnetic moment.

Findings

Sensitivity to a_tau = 0 +0.011 -0.019 at 95% CL

Uses photon-photon interactions in lead-lead collisions at LHC

Achieves improved precision over previous measurements

Abstract

The $\tau$ lepton anomalous magnetic moment: $a_\tau = \frac{g_{\tau}-2}{2}$ was measured, so far, with a precision of only several percents despite its highly sensitivity to physics beyond the Standard Model such as compositeness or Supersymmetry. A new study is presented to improve the sensitivity of the $a_\tau $ measurement with photon-photon interactions from ultra-peripheral lead-lead collisions at LHC. The theoretical approach used in this work is based on an effective Lagrangian and on a photon flux implemented in the MadGraph5 Monte Carlo simulation. Using a multivariate analysis to discriminate the signal from the background processes, a sensitivity to the anomalous magnetic moment $\rm{a_{\tau}}$ = 0 $_{+0.011} ^{-0.019}$ is obtained at 95\% CL with a dataset corresponding to an integrated luminosity of 2 nb$^{-1}$ of lead-lead collisions and assuming a conservative 10\% systematic uncertainty. The present results are compared with previous calculations and available measurements.