Particle Identification in 4th

The importance of particle identification Physics measurements often depend on the efficiency and the purity of an event ensemble, and the efficiency is a product of several small efficiencies for the isolation and identification of each event feature. The 4th detector has been designed from the beginning with particle identification in mind, knowing that we may be seeking small signals and that, in this sense, identification efficiency is equivalent to luminosity. The 4th detector is unique in several respects and is rich in particle identifications measurements some of which are new in high energy physics. The dual-readout calorimeters are responsible for the majority of the “electromagnetic”, “‘muonic”, or “hadronic” tags; the cluster-counting CluCou chamber provides e−μ−π−K−p discrimination in the few-GeV region by a precision measurement of specific ionization; the resolutions of both the tracking chamber and calorimeters through ILCroot are responsible for tagging W → jj and Z → jj decays and for e − γ discrimination; and, the time resolutions of the optical calorimeters (both fiber and crystal) yield the time-of-flight resolutions.