We have investigated the electromagnetic moments of the tau lepton in e + e − → e + γ * γ * e − → e + ττ e − process at the CLIC. We have obtained 95% confidence level bounds on the anomalous magnetic and electric dipole moments for various values of the integrated luminosity and the center of mass energy. We have shown that the e + e − → e + γ * γ * e − → e + ττ e − process at the CLIC leads to a remarkable improvement in the existing experimental bounds on the anomalous magnetic and electric dipole moments.

Potential of the LHC to determine the electromagnetic couplings of the τ lepton is discussed via the process γγ → τ + τ − . Highly improved constraints of the anomalous magnetic and electric dipole moments have been obtained compared to the LEP sensitivity.

We have examined the anomalous electromagnetic moments of the tau lepton in the processes e − γ → ν e τν τ (γ is the Compton backscattering photon) and e − e + → e − γ * e + → ν e τν τ e + (γ * is the Weizsacker-Williams photon) with unpolarized and polarized electron beams at the CLIC. We have obtained 95% confidence level bounds on the anomalous magnetic and electric dipole moments for various values of the integrated luminosity and center-of-mass energy. Improved constraints of the anomalous magnetic and electric dipole moments have been obtained compared to the LEP sensitivity.

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We obtain bounds on the anomalous magnetic and electric dipole moments of the t-quark from a future high-energy and high-luminosity linear electron-positron collider, as the CLIC, with polarized and unpolarized electron beams which are powerful tools for determining new physics. We consider the processes γe − →tbν e (γ is the Compton backscattering photon) and e + e − → e − γ * e + →tbν e e + (γ * is the Weizsacker-Williams photon) as they are one of the most important sources of single top-quark production. For systematic uncertainties of δ sys = 0% (5%), b − tagging efficiency = 0.8, center-of-mass energy of √ s = 3 T eV and integrated luminosity of L = 2 ab −1 the future e + e − collider may put bounds on the electromagnetic dipole momentsâ V andâ A of the top quark of the order of O(10 −2 − 10 −1 ) at the 2σ (3σ) level, which are competitive with those recently reported in previous studies at hadron colliders and the ILC.