Model-independent study on the anomalous $\tau \bar{\tau}\gamma$ couplings at the ILC

TL;DR

This study evaluates the potential of the ILC to set new limits on anomalous tau lepton couplings using photon-photon collisions, showing significant improvements over current experimental bounds.

Contribution

It provides a model-independent analysis of tau anomalous couplings at the ILC through effective Lagrangian approach, with detailed sensitivity estimates.

Findings

Best limits without systematic error: -0.00082<tilde{a}_tau}<0.00050

Electric dipole moment limit: |tilde{d}_tau|<3.5969e-18 e·cm

ILC collisions significantly improve existing bounds on tau anomalous moments

Abstract

The potential of the process $\gamma \gamma \rightarrow \tau \bar{\tau}\gamma$ is examined in a model-independent way using the effective Lagrangian approach for the ILC which is designed with standard configurations of 0.25 TeV/2000 fb$^{-1}$, 0.35 TeV/200 fb$^{-1}$ and 0.5 TeV/4000 fb$^{-1}$. The limits obtained for $\tilde{a}_{\tau}$ and $\tilde{{d}_{\tau}}$ parameters defining the anomalous $\tau \bar{\tau}\gamma$ couplings at $95\%$ confidence level and systematic uncertainties of $\delta_{sys}=0,5,10 \%$ are compared with the experimental results. The best limits obtained without systematic error on the anomalous couplings are $-0.00082<\tilde{a}_{\tau}<0.00050$ and $|\tilde{{d}_{\tau}}|<3.5969 \times 10^{-18}$ $e\,cm$, respectively. Thus, our results show that $\gamma \gamma$ collisions at the ILC lead to a remarkable improvement in the existing experimental limits on the anomalous magnetic and electric dipole moments of the tau lepton.