Speaker
Description
The FCC-ee will operate at unprecedented luminosity, producing large numbers of low-energy electron–positron pairs via incoherent pair creation (IPC) at every bunch crossing, which represent a critical background most significantly at the Z pole. These pairs propagate through the innermost detector layers, dominating the occupancy and bandwidth that drive vertex detector design, and require reliable estimates from beam-beam simulation. We have recently extended the Guinea-Pig program's IPC implemention adding the detector solenoid field during tracking and propagation across the beam-pipe boundary, which changes the predicted innermost-layer occupancy by close to an order of magnitude.
Since current predictions rely on a few long-standing generators such as Guinea-Pig and CAIN, we validate them against WarpX, a modern, independently developed electromagnetic particle-in-cell code. We present work in progress on the modifications needed for WarpX to reproduce the corrected treatment, the observables on which the two codes can be meaningfully compared, and initial results on pair kinematics and propagation, together with an output of the generated pairs in a compact ROOT format within Key4hep for detector simulation and overlay with physics events.