Particle identification at FCC-ee

Guy Wilkinson

doi:10.1140/epjp/s13360-021-01810-4

Abstract

Equipping an experiment at FCC-ee with particle identification (PID) capabilities, in particular the ability to distinguish between hadron species, would bring great benefits to the physics programme. Good PID is essential for precise studies in quark flavour physics and is also a great asset for many measurements in tau, top, and Higgs physics. The requirements placed by flavour physics and these other applications are surveyed, with an emphasis on the momentum range over which PID is necessary. Possible solutions are discussed, including classical RICH counters, time-of-flight systems, and dE/dx and cluster counting. Attention is paid to the impact on the global detector design that including PID capabilities would imply.

Highlights

Particle identification (PID), here defined as the ability to distinguish between hadron species, is essential for several areas of collider physics, in particular flavour and spectroscopy studies, and brings significant benefits for many others
Among the many studies that will be pursued at FCC-ee, it is flavour physics and spectroscopy, both pursued at the Z pole, that have the greatest reliance on PID
Three main applications exist, which can be illustrated with reference to the decay Bs0 → Ds± K ∓, which is an important mode in CP-violation studies for measuring the unitarity triangle angle γ:

Summary

Introduction

Particle identification (PID), here defined as the ability to distinguish between hadron species, is essential for several areas of collider physics, in particular flavour and spectroscopy studies, and brings significant benefits for many others. Conceptual designs for FCC-ee experiments have not placed great emphasis on this capability. In this brief article, the PID requirements at the FCC-ee are assessed, and a summary is given of the various detector technologies that are available to meet these needs. It is seen that the problem is challenging, and that more studies and developments are necessary to arrive at a satisfactory solution

The importance of PID in the FCC-ee physics programme

Candidate PID technologies

Time-of-flight detectors

Conclusions

Findings

Methods