Measuring CP nature of top-Higgs couplings at the future Large Hadron electron Collider

• Main Authors: Baradhwaj Coleppa, Mukesh Kumar, Satendra Kumar, Bruce Mellado
• Format: Article
• Language: English
• Published: Elsevier 2017-07-01
• Series: Physics Letters B
• Subjects: Electron–proton collision; Top-Higgs coupling; Top polarisation
• Online Access: http://www.sciencedirect.com/science/article/pii/S0370269317303568

We investigate the sensitivity of top-Higgs coupling by considering the associated vertex as CP phase (ζt) dependent through the process pe−→t¯hνe in the future Large Hadron electron Collider. In particular the decay modes are taken to be h→bb¯ and t¯ → leptonic mode. Several distinct ζt dependent features are demonstrated by considering observables like cross sections, top-quark polarisation, rapidity difference between h and t¯ and different angular asymmetries. Luminosity (L) dependent exclusion limits are obtained for ζt by considering significance based on fiducial cross sections at different σ-levels. For electron and proton beam-energies of 60 GeV and 7 TeV respectively, at L=100 fb−1, the regions above π/5<ζt≤π are excluded at 2σ confidence level, which reflects better sensitivity expected at the Large Hadron Collider. With appropriate error fitting methodology we find that the accuracy of SM top-Higgs coupling could be measured to be κ=1.00±0.17(0.08) at s=1.3(1.8) TeV for an ultimate L=1ab−1.