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

Abstract

In this work we study the potential of the processes $e^{+}{e}^{-}\to e^{+}{\gamma }^{\ast }{e}^{-}\to e^{+}\tau {\bar{\nu }}_{\tau }{\nu }_e$ and $e^{+}{e}^{-}\to e^{+}{\gamma }^{\ast }{\gamma }^{\ast }{e}^{-}\to e^{+}{\nu }_{\tau }{\bar{\nu }}_{\tau }{e}^{-}$ 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}$f{b}^{-1}$ and center-of-mass energy of 3\hspace{1mm}$TeV$, we derive $95\%C.L.$ limits on the dipole moments: ${\mu }_{{\nu }_{\tau }}\le 1.44\times 10^{-6}{\mu }_B$ and $d_{{\nu }_{\tau }}\le 2.78\times 10^{-17}ecm$ in the ${\gamma }^{\ast }{e}^{-}$ collision mode and of ${\mu }_{{\nu }_{\tau }}\le 3.4\times 10^{-7}{\mu }_B$ and $d_{{\nu }_{\tau }}\le 6.56\times 10^{-18}ecm$ with the ${\gamma }^{\ast }{\gamma }^{\ast }$ collision mode, improving the existing limits.

Comments: 25 pages, 14 figures