Improved bounds on the dipole moments of the tau-neutrino at high-energy $\gamma^* e^-$ and $\gamma^* \gamma^*$ collisions: ILC and CLIC

Abstract

In this work we study the potential of the processes $e^+e^- \to e^+\gamma^* e^- \to e^+\tau \bar\nu_\tau \nu_e $ and $e^+e^- \to e^+\gamma^* \gamma^* e^- \to e^+\nu_\tau \bar\nu_\tau e^- $ at a future high-energy and high-luminosity linear electron positron collider, such as the ILC and CLIC to study the sensibility on the anomalous magnetic and electric dipole moments of the tau-neutrino. For integrated luminosity of 590\hspace{1mm}$fb^{-1}$ and center-of-mass energy of 3\hspace{1mm}$TeV$, we derive $95 \% \hspace{1mm}C. L.$ limits on the dipole moments: $\mu_{\nu_\tau}\leq 1.44 \times 10^{-6}\mu_B$ and $d_{\nu_\tau}\leq 2.78 \times 10^{-17}\hspace{1mm} e\hspace{0.5mm} cm$ in the $\gamma^* e^-$ collision mode and of $\mu_{\nu_\tau}\leq 3.4 \times 10^{-7}\mu_B$ and $d_{\nu_\tau}\leq 6.56 \times 10^{-18}\hspace{1mm} e\hspace{0.5mm}cm$ with the $\gamma^*\gamma^*$ collision mode, improving the existing limits.