Exploring the anomalous top–Higgs FCNC couplings at the electron proton colliders

Abstract

We perform an updated analysis on the searches for the anomalous FCNC Yukawa interactions between the top quark, the Higgs boson, and either an up or charm quark tqh, q = u, c). We probe the observability of the FCNC top-Higgs couplings through the processes e − p → ν et → ν e hq signal I) and e − p → ν e hb signal II) at the proposed electron proton ep colliders, where the Higgs boson decays to a bb pair. We find that at the high-luminosity (1 ab −1 ) ep colliders where the electrons have a polarization of 80% and electron energy is typical 60 GeV, the 2σ upper limits on Brt → uh) are 0.15×10 −2 2.9×10 −4 ) at the 7TeV@LHeC 50TeV@FCC-eh) for signal I and 0.15 × 10 −2 2.2 × 10 −4 ) for signal II. We also give an estimate on how the sensitivity (taking signal I as example) would change when we reduce the electron beam energy from 60 to 50 GeV or even 40 GeV due to the cost. The conclusion is that the discovery potential is reduced 8.7% (29.4%) if the electron beam changes from 60 to 50 (40) GeV at the 7 TeV LHeC, and 16.8% (19.8%) at the 50 TeV FCC-eh.

Top FCNC interactions through dimension-six four-fermion operators at the electron proton collider

“…This is obtained by assuming the experimental uncertainty to be as high as 30%. While at the LHeC, most efforts have been put at dimension four FCNC operators [25][26][27][28][29][30]. The exact process e − p → e − t has been considered at a recent paper [25] while focusing on anomalous Ztq couplings.…”

Probing top quark FCNC couplings in the triple-top signal at the high energy LHC and future circular collider

“…The possibility of the top quark anomalous FCNC couplings with light quarks (q = u, c) and a gauge bosons (g, H, Z, γ) is explored in a model-independent way considering the most general effective Lagrangian approach [58,60]. In the search of anomalous FCNC interactions at high energy colliders, this approach has been extensively studied in literature for lepton and hadron colliders [21][22][23][24][25][26][27][28][29][30][31][32][61][62][63][64][65][66][67][68][69][70][71]. In this framework, these FCNC vertices are described by higher-dimensional effective operators L tqX FCNC independently from the underlying theory.…”

TOP Production at the electron proton colliders

“…We consider two signal productions that contain the top-Higgs FCNC couplings [8]. One is signal.I : e − p → ν et → ν e hq → ν e bbq,…”