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

Abstract 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 doublet model including the exotic vectorlike X quark (VLQ- X ) with an electric charge , we study the production of the VLQ- X decaying into at the future Compact Linear Collider (CLIC) with 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 exclusion capabilities and discovery reaches, respectively, on the mass of the VLQ- X as well as the relevant parameters ( for GeV and the coupling strength for GeV) for some typical luminosities at the 3 TeV CLIC.