Study of Top quark FCNC coupling structure at LHeC and FCC-he

Speaker :  Dr. Subhasish Behera (National Taiwan U.)

Abstract :
We investigate the possible presence of Flavor Changing Neutral Current (FCNC) interactions of the top quark with Z−boson, gluon and photon. We consider the Large Hadron-electron Collider (LHeC) to study the tqZ FCNC coupling through e−p → e−t process and tqγ and tqg through e−p → e−tj at the Future Circular Collider in the proton-electron mode (FCC-he). Focusing on disentangling the effects of different couplings that could be present, we exploit the presence of the scattered electron, the angular distribution of which is sensitive to the type of coupling involved. Top quark polarisation accessed through the angular distribution of the decay lepton provides additional handle in identifying the nature of the couplings. Further, we demonstrate the potential of electron beam polarisation in distinguishing the left-handed and right-handed couplings of Z−boson, gluon and photon separately.