Study Of Top Partner Single Production At High Energy Colliders

The Standard Model of particle physics is a theory based on the gauge theory which describes the strong,weak and electromagnetic interactions of fundamental particles.It is one of the most perfect theories in the particle physics,and has been tested by many experiments.However,there are many unexplainable problems in both the theory itself and experimental observations(for example,the theory itself has fine-tuning problem,and cannot provide dark matter candidate in experiment),and these problems have not been reasonably explained.So theorists have put forward many theoretical models beyond the Standard Model to explore new physics.The fine-tuning problem stems from the quadratic divergence to the Higgs mass caused by the top quark,W±,Z boson loops and Higgs self-energy in the Standard Model.A common method to alleviate the fine-tuning problem is introducing the top partner in new physics models.In this paper,we first give a review of the Standard Model of particle physics,and briefly introduce the Littlest Higgs Model with T-parity and Vector-Like Quark Model,then introduce the relevant knowledge of Collider Physics and the current situation of direct search for top partner in experiments.Finally,the top partner was studied from the following two aspects in our work:(1)Focus on the linear collider,we study the single top partner production in the tZ channel at ey collision in the littlest Higgs Model with T-parity.According to the leptonic or the hadronic decays of the W and Z from the top partner,we choose two decay modes for comparison.For the Mode A(B),the excluded ability of this process at(?)=3 TeV can’t exceed the existing experimental limits.We also considered the initial state radiation effect and find that this effect will reduce the excluding ability of ey collision on the the top partner mass by about 10 GeV.Besides,the ability to exclude the LHT parameter space at ey collision will complement the existing experiments.(2)We investigate the single production of T decaying into Wb in the Vector-Like Quark Model with 4 flavour scheme at the LHC and future high energy pp colliders,such as HL-LHC,HE-LHC and FCC-hh.By performing a detailed detector simulation and the background analysis,we display the excluding capability on the top partner T at different collider with different integrated luminosity at 95%confidence level.We find that the excluding capability is enhanced obviously with the increase of the collision energy and the HE-LHC and FCC-hh have greater advantage in high mT regions.For the high integrated luminosity of 3000 fb-1:①the HL-LHC can exclud the region g*>0.06～0.09 with mT ∈[1300 GeV,2000 GeV];②the HE-LHC can exclud the regions g*>0.06～0.06 with mT ∈[1300 GeV,1700 GeV]and g*>0.04～0.08 with mT ∈[1700 GeV,3000 GeV];③the FCC-hh can exclud the regions g*～0.04～0.04 with mT ∈[1300 GeV,1900 GeV]and g*>0.03～0.03 with mT ∈[1900 GeV,3000 GeV].Besides,we also display the discovering capability on the top partner at different colliders.