Search for an exotic vectorlike X-quark in same-sign dilepton final states at the future 3 TeV CLIC

Vectorlike quarks(VLQs)with masses at the TeV-scale have been predicted in many new physics scenarios beyond the Standard Model(SM).Based on a simplified(X,T)doublet model including the exotic vectorlike X quark(VLQ-X)with an electric charge 5/3,we study the production of the VLQ-X decaying into tW at the future Compact Linear Collider(CLIC)with √s=3 TeV including the initial state radiation and beamstrahlung effects.We focus on the final signals,including same-sign dileptons(electrons or muons),at least one b-tagged jet,and large missing transverse momentum.By performing detailed signal-to-background analyses and detector simulations,we obtain the 2σexclusion capabilities and discovery reaches,respectively,on the mass of the VLQ-Xmx as well as the relevant parameters(Br(X→_(t)W))for mx≥1500GeV and the coupling strength g^(*) for mx≥1500 GeV)for some typical luminosities at the 3 TeV CLIC.