Constraining the top quark effective field theory using the t ¯ tg production at future lepton colliders (original) (raw)

Our main aim in this paper is to constrain the effective field theory describing the top quark couplings through the e − e + → t ¯ tg process. The analysis is carried out considering four different center-of-mass energies of 500, 1000, 1500, and 3000 GeV including a realistic simulation of the detector response and the main sources of background processes. The study is performed on the benchmark scenarios proposed by the future electron-positron colliders such as CLIC and ILC. The expected limits at 95% CL are derived on the new physics couplings such as t ¯ tγ , t ¯ tZ, hgt ¯ t, and t ¯ tg for each benchmark scenario using the dileptonic t ¯ t final state. We show that the 95% CL limits on dimensionless Wilson coefficients ¯ ci determined in this analysis could be probed down to 10 −4. Our findings indicate that a future lepton collider operating at a center-of-mass energy above the t ¯ t threshold would improve the constraints by orders of magnitude with respected to the LHC expectations. CONTENTS