Speaker
Description
Improving the precision of the top quark mass measurement is essential for understanding the properties of the Higgs field at high energy scales and the vacuum stability of the universe. In previous measurements with inclusive top quark decays (such as the lepton + jets final state), the dominant uncertainties arose from the energy reconstruction of QCD jets. We have developed a method to extract the mass from a high-momentum lepton and a J⁄ψ meson in the decay chain of the top quark. By using only lepton momentum, the uncertainties associated with jet reconstruction have been reduced to below 100 MeV. However, uncertainties related to the modeling of top quark production and decay are now dominant and must be controlled. A rigorous estimation has shown that the uncertainties arising from the modeling of tt ̅ events can be suppressed to below 1 GeV, bringing them to the same level as the statistical uncertainty. The method of this measurement using J⁄ψ meson and the estimation of the systematic uncertainties are presented.
