We discuss the potential of the photon-induced two lepton final states at the LHC to explore the phenomenology of the Kaluza-Klein (KK) tower of gravitons in the scenarios of the Arkani-Hamed, Dimopoulos and Dvali(ADD) model and Randall-Sundrum (RS) model. The sensitivity to model parameters can be improved compared to the present LEP or Tevatron sensitivity.

Potential of the LHC to explore the phenomenology of the Kaluza-Klein (KK) tower of gravitons in the scenarios of the Arkani-Hamed, Dimopoulos and Dvali(ADD) model and Randall-Sundrum (RS) model is discussed via the process γγ → γγ including the Standard Model one loop diagram. The improved constraints on model parameters have been obtained compared to the LEP and Tevatron 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.

We study the potential of the exclusive pp → pℓ − ℓ + p process to probe excited leptons at the LHC which is known to be one of the most clean channel at the hadron colliders. The sensitivity of the model parameters is obtained 95% confidence level by considering three forward detector acceptances; 0.0015 < ξ < 0.5, 0.0015 < ξ < 0.15 and 0.1 < ξ < 0.5. * sceminan@cumhuriyet.edu.tr

In this study, light-by-light (LBL) scattering with initial polarized Compton backscattered photons at the CLIC, induced by axion-like particles (ALPs), is investigated. The total cross sections are calculated assuming CP-even coupling of the pseudoscalar ALP to photons. The 95% C.L. exclusion region for the ALP mass and its coupling constant f is presented. The results are compared with CLIC bounds previously obtained for the unpolarized case. It is shown that the bounds on f for the polarized beams in the region with collision energy of 3000 GeV and integrated luminosity of 4000 fb are on average 1.5 times stronger than the bounds for the unpolarized beams. Moreover, our CLIC bounds are stronger than those for all current exclusion regions for GeV. In particular, they are more restrictive than the limits that follow from the ALP-mediated LBL scattering at the LHC.