Time resolution of the ALICE Time-Of-Flight detector with the first Run 3 pp collisions at ${\bf \sqrt{\textit{s}} = 13.6}$ TeV

TL;DR

This paper reports on the upgraded ALICE Time-Of-Flight detector's performance during Run 3 at the LHC, achieving a timing resolution better than 80 ps, which enhances particle identification capabilities.

Contribution

It presents the upgraded TOF detector's operation, calibration procedures, and performance results, demonstrating improved timing resolution in Run 3 pp collision data.

Findings

Timing resolution better than 80 ps achieved

Successful implementation of upgraded electronics and algorithms

Enhanced particle identification capabilities expected for future runs

Abstract

Particle identification (PID) is a fundamental aspect of the ALICE detector system, central to its heavy-ion and proton-proton physics programs. Among the different PID strategies, ALICE uses the Time-Of-Flight (TOF) detector to identify particles at intermediate momenta ($0.5 < p_{\rm T} < 4$ GeV/$c$). The ALICE TOF detector performed successfully during the first ten years of LHC operations. During the Long Shutdown 2, many ALICE sub-detectors, including TOF, were upgraded to fully leverage the targeted 50 kHz interaction rate of Pb-Pb collisions, which required the implementation of a continuous readout scheme. The TOF detector electronics were upgraded and refurbished, while processing algorithms for data quality control, reconstruction, calibration, and analysis were rewritten. This paper presents the upgraded TOF detector operation and calibration procedures and its performance in terms of timing resolution, a key factor for particle separation in ALICE analyses. Using 2022 pp collision data at $\sqrt{s} = 13.6$ TeV from Run 3, the time resolution of the detector was estimated with two independent methods, both yielding consistent results, better than 80 ps. Despite the excellent performance already achieved, further improvements are expected after additional detector commissioning and refined calibration procedures, thus enhancing the ALICE PID capabilities for Run 3 and beyond.