Singlet vector-like T quark production in association with Wb at the CLIC

In a simplified model including an SU(2)singlet vector-like top quark T(VLT)with charge 2/3,we investigate the associated production of Wb with VLT at a Compact Linear Collider(CLIC).Focusing on the T→Wb decay channel,we discuss two decay models:e+e-→TW+b→(l-vb)(jjb)and e+e-→TW+b→(jjb)(l+νb).In this paper,we consider recent experimental limits including the electroweak precision observables,the width of the top quark,and the direct LHC searches.Through a detailed detector simulation,we show the exclusion and discovery capability on the T at 3 TeV CLIC,where the initial state radiation effect has also been considered.The results show that it is promising to detect the VLT at future high-energy e+e-colliders.

Single top partner production in the tZ channel at eγ collision in the littlest Higgs model with T-parity

Introducing the top partner is a common way to cancel the largest quadratically divergent contribution to the Higgs mass induced by the top quark. In this work, we study single top partner production in the tZ channel at eγ collision in the littlest Higgs model with T-parity(LHT). Since it is well known that polarized beams can enhance the cross section, we analyze the signal via polarized electron beams,and photon beams. we have selected two decay modes for comparison, based on the leptonic or the hadronic decays of the W and Z from the top partner. We then construct a detailed detector simulation, and choose a set of cuts to enhance signal significance. For mode A(B), the capacity for exclusion in this process at s1/2=3TeV is comparable to the current experimental limits with L=1000(500) fb-1. If the integrated luminosity can be increased to 3000 fb-1, the top partner mass+mTcan be excluded up to 1350(1440) GeV at 2σ level. We also considered the initial state radiation effect, and find that this effect reduces the excluding ability of the eγ collision on the the top partner mass by approximately 10 GeV. Moreover, the ability to exclude the LHT parameter space at eγ collision complements the existing research.

T-odd top partner pair production in the dilepton final states at the LHC in the littlest Higgs Model with T-parity

In the littlest Higgs model with T-parity, we discuss the pair production of the T-odd top partner （T_） that decays almost 100% into the top quark and the lightest T-odd particle （AH）. Considering the current constraints, we investigate the observability of the T-odd top partner pair production through the process pp→T_T_ →ttAHAH in the final states with two leptons at 14 TeV LHC. We analyze the signal significance and found that the lower limits on the T-odd top partner mass are approximately 1.2 TeV, 1.3 TeV, and 1.4 TeV at the 2or confidence level at 14 TeV LHC with an integrated luminosities of 30 fb^-1, 100 fb^-1, and 300 fb^-1, respectively. This lower limit can be increased to approximately 1.5（1.6） TeV if we used 1000（3000） fb^-1 of the integrated luminosity.