Speaker
Description
In recent years, the next generation electron–positron collider projects—including CEPC, FCC-ee, and ILC, have emerged as the leading platforms for precision physics, targeting measurements of the Higgs boson, electroweak observables and flavor physics. In particular, the precision studies of charm and hadrons place the most stringent demands on particle identification (PID) over a wide momentum range, making robust PID a cross-cutting priority and a shared technical challenge across all these facilities. As the primary tracking detector adopted in the baseline designs of these colliders, the Time Projection Chamber (TPC) offers a low material budget and excellent spatial resolution. Crucially, its PID capability enabled by high-granularity pixelated readout with pad sizes down to a few hundred micrometres and cluster-counting (d$n$/d$x$) techniques, that is a general central R&D focus at CERN and within the global DRD1 community. Optimizing the TPC readout for PID is therefore a timely and essential task that directly determines the flavor physics reach of the proposed future e$^+$ e$^-$ colliders.
This talk presents the updated results on PID performance and pad-size optimization for the TPC. We have developed a full simulation framework based on Geant4 and Garfield++, covering the entire chain from primary ionization and electron drift to avalanche multiplication and digitized signal readout. The framework enables a realistic evaluation of PID using both traditional d$E$/d$x$ and d$n$/d$x$ methods, and implements a layered truncated-mean algorithm to mitigate the effects of delta electrons. We have systematically evaluated the $\pi/K$ separation power for pad sizes ranging from 55 $\mu$m to 500 $\mu$m, considering both physics performance and engineering feasibility, and have also extended our study to preliminarily evaluate the impact of beam-induced backgrounds on PID performance. In parallel, a full drift length (2.9 m) TPC prototype has been constructed and commissioned, equipped with Micromegas modules and TEPIX readout chips, to experimentally validate the simulation predictions. This talk will present the latest progress on the pad-size optimization, beam-induced background effect studies and prototype development. All studies will provide essential guidance for the TPC technology in future high energy colliders.
