Separation of two electromagnetic or electromagnetic - hadronic showers in CALICE SiW ECAL and ILD

TL;DR

This paper investigates methods to distinguish overlapping electromagnetic and electromagnetic-hadronic showers in highly granular calorimeters, crucial for accurate particle reconstruction at future high-energy electron-positron colliders.

Contribution

It presents experimental and simulation results on separating overlapping showers using multiple PFA algorithms in a highly granular calorimeter system.

Findings

Effective separation of overlapping showers demonstrated

Comparison of three PFA algorithms shows varying performance

Results improve particle identification at high energies

Abstract

CALICE collaboration is developing highly granular calorimeters suitable for individual reconstruction of particles in the jets using Particle Flow Algorithms. Such calorimeters should provide the best jet energy resolution at future high energy $e^{+}e^{-}$ colliders. At high jet energies, typically above 70-100 GeV, the jet particle showers start to overlap, and the resolution is determined by the ability to separate them. Here, we present the results on the separation of two overlapping electromagnetic or electromagnetic - hadronic showers obtained by mixing of the single shower events collected with CALICE SiW ECAL and AHCAL physics prototypes during beam tests at CERN'07 and FermiLab'11, and using International Large Detector (ILD) Monte Carlo simulations. We use three available PFA reconstruction programs (Pandora, Garlic and Arbor).