Study on CEPC performances with different collision energies and geometric layouts

Abstract: Circular Electron-Positron Collider(CEPC) is one of the largest plans in high energy physics study at China, which would serve as Higgs Factory firstly and then upgrade to a hadron collider. In this paper we give the 50km and 100km design in both single ring and double ring schemes, including $Z$ boson and $W$ boson and Higgs boson by using the optimized method. Also, we give the potential of CEPC running at $Z$ and $W$ poles. And we analysis the relationship of luminosity with circumference and filling factor, which gives a way to evaluate the choice of geometry. What's more, we compare the nominal performance of CEPC-SPPC and LHC and FCC.