Feasibility at the LHC, FCC-he and CLIC for sensitivity estimates on anomalous $\tau$-lepton couplings

Abstract

In this paper, we present detailed studies on the feasibility at $pp$, $e^-p$ and $e^+e^-$ colliders for model-independent sensitivity estimates on the total cross-section and on the anomalous $\tau^+\tau^-\gamma$ interaction through the tau pair production channels $pp \to p\tau\bar \tau \gamma p$, $e^-p \to e^- \tau\bar \tau \gamma p$ and $e^+e^- \to e^+ \tau\bar \tau \gamma e^-$ at the $\gamma^*\gamma^* \to \tau^+\tau^-\gamma$ mode. Measurements of the anomalous couplings of the $\tau$-lepton $\tilde{a}_\tau$ and $\tilde{d}_\tau$ provide an excellent opportunity to probing extensions of the Standard Model. We estimate the sensitivity at the $95\%$ Confidence Level, and we consider that the $\tau$-lepton decays leptonically or semi-leptonically. We found that of the three considered colliders, the future CLIC at high energy and high luminosity should provide the best sensitivity on the dipole moments of the $\tau$-lepton $\tilde a_\tau= [-0.00128, 0.00105]$ and $ |\tilde{d}_\tau({\rm ecm})|= 6.4394\times 10^{-18}$, which show a potential advantage compared to those from LHC and FCC-he.