The TICL (v4) reconstruction at the CMS Phase-2 High Granularity Calorimeter Endcap

In this note we show the development and results achieved with the new version of TICL (The Iterative CLustering) (version 4), being developed for particle flow reconstruction in CMS during Phase 2 of the LHC, using the High Granularity Calorimeter (HGCAL). This new version consists in a new longitudinal pattern recognition algorithm (CLUE3D) for associating 2D layer clusters created by the CLUE clustering algorithm, and in a new linking algorithm that has been developed for connecting together the tracksters obtained by CLUE3D, and improve the Particle Flow reconstruction and interpretation. The new longitudinal pattern recognition algorithm is named CLUE3D, while the linking algorithm uses geometrical association to connect aligned tracksters exploiting energy and timing information to select for compatibility, so as to remove possible spurious links.