A novel layered reconstruction framework for longitudinal segmented electromagnetic calorimeter

摘要: In future high-energy physics experiments, the electromagnetic calorimeter (ECAL) will operate in exceptionally high-luminosity. An ECAL featuring layered readout in the longitudinal direction and precise time-stamped information offers a multi-dimensional view, enriching our comprehension of the showering process of electromagnetic particles in high-luminosity environments. And it is taken as the baseline design for several new experiments, including the planned upgrades of the current running experiments. Reconstructing and matching the multi-dimensional information across different layers poses new challenges in utilizing layered data effectively. This work introduces a novel layered reconstruction framework for the ECAL with a layered readout information structure and develops the layered clustering algorithm. It expands the concept of clusters from planes to multiple layers. Additionally, this work presents the corresponding layered cluster correction methods, investigates the transverse shower profile, which is utilized for overlapping clusters splitting, and develops the layered merged $\pi^0$ reconstruction algorithm based on this framework. By incorporating energy and time information in 3-dimension, this framework provides a suitable software platform for the preliminary research of longitudinal segmented ECAL and new perspectives in physics analysis.

Furthermore, taking the PicoCal in LHCb Upgrade \Rmnum{2} as a concrete example, the performance of the framework has been preliminarily evaluated using single photons and $\pi^{0}$ particles from the neutral $B^0$ meson decay $B^0\rightarrow\pi^+\pi^-\pi^0$ as benchmarks. The results demonstrate that compared to the unlayered framework, utilizing this framework for longitudinal segmented ECAL significantly enhances the position resolution and the ability to split overlapping clusters, thereby improving the reconstruction resolution and efficiency for photons and $\pi^0$s.