Probing the Anomalous FCNC tqγ Couplings at Large Hadron Electron Collider

Abstract

We investigate the anomalous flavour changing neutral current (FCNC) interactions of top quark through the process − → − ± + . We calculate the signal and background cross sections in electron-proton collisions at Large Hadron electron Collider (LHeC) with a 7 TeV proton beam from the LHC and a new 60 GeV electron beam from energy recovery linac (ERL). We study the relevant background processes including one electron and three jets in the final state. The distributions of the invariant mass of two jets and an additional jet tagged as -jet are used to account for signal and background events after the analysis cuts. We find upper bounds on anomalous FCNC couplings of the order of 10 −2 at LHeC for a luminosity projection of 500 fb −1 together with the fast simulation of detector effects. As a matter of interest, we analyze the sensitivity to the couplings ( , ) and find an enhanced sensitivity to at the LHeC when compared to the results from the HERA.

Top and EW physics at the LHeC and the FCC-eh

“…The expected statistical significance as a function of the integrated luminosity is presented in Fig. 1 (lower left) for different values of the coupling strength λ [7]. Assuming a coupling strength of λ = 0.01 an observation with 5 σ standard deviations is expected already at an integrated luminosity of 100 fb −1 .…”

“…The polarization asymmetry in NC-EW interactions as a function of Q 2 for the FCC-ep [2] (middle left). Expected sensitivities as a function of the integrated luminosity on the SM and anomalous Wtb couplings [6] (middle right), on FCNC tuγ couplings [7] (lower left), and on FCNC t → uH branching ratios [8] (lower right).…”

An experiment for electron-hadron scattering at the LHC

“…The LHeC also provides access to Flavor Changing Neutral Current (FCNC) processes driven by the γ tq and Ztq vertexes, where q = u, c [28,29]. This is achieved by measuring the process e − p → e − W ± q + X .…”

Top and Electroweak Physics at the LHeC and the FCC-eh

“…Figure 2: Expected sensitivities as a function of the integrated luminosity on the SM and anomalous Wtb couplings [11] (upper left), on |V ts | (upper right) [16], on FCNC t → qV branching ratios (lower left) [20], and on FCNC t → uH branching ratios [22] (lower right).…”

“…Single top quark NC DIS production can be used to search for Flavor Changing Neutral Current (FCNC) tuγ, tcγ, tuZ, and tcZ couplings [20] as given in…”