Speaker
Description
Measurement of Muon Ionization Energy Loss in the High-Granularity Dual-Readout Calorimeter
We report on the response of the High-Granularity Dual-Readout Module (HG-DREAM) to muons with energies between 100 and 160 GeV, measured at the CERN SPS H8 beam line. HG-DREAM samples showers with two types of fibers: scintillating fibers, and Cherenkov fibers of fused silica and clear plastic. Comparing the two signals event by event is the basis of the dual-readout technique. Although the module was designed for hadronic calorimetry, its dual-readout structure also allows the energy lost by muons to be separated into its radiative and non-radiative components, an interesting by-product for dual-readout calorimetry at the FCC-ee and other future collider experiments. A muon traversing the calorimeter loses energy through ionization and radiative processes, mainly bremsstrahlung. The scintillating fibers detect both components, while the Cherenkov fibers are sensitive only to the radiative component. When the muons travel along the fiber direction, their primary Cherenkov radiation falls outside the fibers' numerical aperture. When both channels are calibrated with electromagnetic showers from positrons, their responses to the radiative component are equal, and it cancels in the difference S − C. What remains is the non-radiative energy loss, which is constant over the studied energy range, while the radiative contribution grows with muon energy. This separation is possible only with the electromagnetic calibration where we can isolate the ionization loss. We present the measured scintillation, Cherenkov and S − C signals as a function of muon energy, and compare them with the Geant4 simulation.
