Speaker
Description
Calorimeters based on liquified noble gases have demonstrated excellent performance over the past decades in various particle physics experiments, offering good energy resolution, linearity, uniformity, and stability. To achieve the goals of FCC’s ambitious physics programme, future detector technologies must meet stringent performance requirements.
As part of an extensive R&D programme, the ALLEGRO (A Lepton-Lepton Collider Experiment with Granular Read-Out) detector concept is being developed as a general-purpose detector for the FCC-ee, designed to deliver high jet energy resolution, excellent particle identification and low systematic uncertainties.
Its electromagnetic sampling calorimeter combines noble liquid technology with multilayer printed circuit boards for signal readout, enabling a highly granular design. It features 11 longitudinal layers with cell sizes of about 2 × 1.8 cm² in the θ × φ plane. The use of a strip layer with four times finer segmentation is under investigation to support particle flow reconstruction methods and to improve the pi0 rejection. Since π⁰s decay into two photons that often produce overlapping showers, they can mimic single photon signatures in the detector. To address this, shower shape variables such as lateral width and energy distribution profiles, are being studied to characterize these subtle differences and improve discrimination.
Simulation studies are ongoing to evaluate the impact of various strip layer configurations on π⁰ rejection performance. Preliminary results indicate that different shower shape variables are optimal at different energy ranges. Additionally, it was observed that showers tend to develop deeper in the detector than initially expected, suggesting that pushing the strip layer further back than originally planned could enhance performance.
This poster will present the current status of the calorimeter design and simulation studies, with a particular focus on photon/π⁰ separation, and will outline future strategies for optimizing the design and preparations for the prototyping phase.
