Improving t t reconstruction in the dilepton channel at future lepton colliders
Abstract
A future lepton collider, such as the proposed CLIC or ILC, would allow to study top quark properties with unprecedented precision. In this paper, we present a method to reconstruct the t t decay in the dilepton channel at future e+e- colliders. We derive a simple, closed analytical expression for the neutrino four-momenta as a function of the W boson mass and develop a maximization procedure to find the optimal solution for the reconstruction of the full t t event. We show that our method is able to reconstruct neutrino four-momenta with an error of less than 2 \, \% in 60 \, \% of the times. Finally, we test the performance of this reconstruction method in the calculation of the helicity fractions of the W boson. A precise measurement of these observables could be used to probe new physics effects in the Wtb vertex. We find that, from a large t t sample, our reconstruction method allows to calculate these observables with an accuracy better than 1 \, \%.