ALICE FIT data processing and performance during LHC Run 3

TL;DR

The paper discusses the ALICE experiment's upgraded FIT detector for LHC Run 3, focusing on its data processing, performance, and ability to accurately measure collision parameters at higher luminosities.

Contribution

It introduces the redesigned FIT detector, detailing its simulation, software, data processing, and performance metrics during LHC Run 3.

Findings

High trigger efficiency achieved

Precise collision time measurement demonstrated

Effective centrality and multiplicity resolution

Abstract

During the upcoming Run 3 and Run 4 at the LHC the upgraded ALICE (A Large Ion Collider Experiment) will operate at a significantly higher luminosity and will collect two orders of magnitude more events than in Run 1 and Run 2. A part of the ALICE upgrade is the new Fast Interaction Trigger (FIT). This thoroughly redesigned detector combines, in one system, the functionality of the four forward detectors used by ALICE during the LHC Run 2: T0, V0, FMD and AD. The FIT will monitor luminosity and background, provide feedback to the LHC, and generate minimum bias, vertex and centrality triggers, in real time. During the offline analysis FIT data will be used to extract the precise collision time needed for time-of-flight (TOF) particle identification. During the heavy-ion collisions, FIT will also determine multiplicity, centrality, and event plane. The FIT electronics designed to function both in the continuous and the triggered readout mode. In these proceedings the FIT simulation, software, and raw data processing are briefly described. However, the main focus is on the detector performance, trigger efficiencies, collision time, and centrality resolution.