The CMS Silicon Pixel detector for HL-LHC

The LHC is planning an upgrade program which will bring the luminosity to about 5~$\times10^{34}$~cm$^{-2}$s$^{-1}$ in 2026, with the goal of an integrated luminosity of 3000 fb$^{-1}$ by the end of 2037. This High Luminosity scenario, HL-LHC, will present new challenges of higher data rates and increased radiation. To maintain its physics potential in this harsh environment, the CMS detector will undergo a major upgrade program known as the Phase II upgrade. The new Phase II pixel detector will require a high bandwidth readout system and highly radiation tolerant sensors and on-detector ASICs. Several technologies for the sensors are being studied. Serial powering schemes are under consideration to accommodate significant constraints on the system. These prospective designs, as well as new layout geometries that include very forward pixel discs with acceptance extended from $\vert\eta\vert<2.4$ to $\vert\eta\vert<4$, are presented together with performance estimates.