Commissioning of the ALICE TPC

Abstract

The main tracking detector of the ALICE experiment at the LHC is a large time projection chamber. This detector has been fully assembled and, before being lowered to the underground experimental area, was commissioned with cosmic rays and tracks produced by an UV laser system. This paper presents the commissioning including preliminary results from the analysis of data on noise, electron diffusion, drift velocity and spatial resolution.

Heavy-ion physics with ALICE

“…The ALICE experimental apparatus, sketched in figure 1, consists of two main components: a central detector and a muon arm. The central detector, covering mid-rapidity (|η| < 0.9) 1 For the full author list see the appendix. a Due to the limited rate capability of the ALICE detector, we plan to limit the luminosity in our interaction region to a maximum of 10 31 cm −2 s −1 .…”

“…over full azimuth, is contained inside a large solenoidal magnet providing a magnetic field |B| < 0.5 T. It includes, from the interaction region outwards, a vertex detector-the inner tracking system (ITS)-made of six layers of silicon microdetectors (Si pixels, Si drifts and Si strips), a large time projection chamber (TPC) (see [1]), a transition radiation detector (TRD) for electron identification and a time-of-flight detector (TOF) (see [2]) for the identification of pions, kaons and protons. The central detector is completed by two detectors with reduced azimuthal acceptance: the high momentum particle identification detector (HMPID)-an array of ring imaging Cherenkov detectors for particle identification at high momentum-and the photon spectrometer (PHOS)-a high-resolution electromagnetic calorimeter made of high density scintillator crystals (see [3]).…”

The Role of Mesons in Light-by-Light Scattering at Low Transverse Momentum

“…In this limit of p t , the possibility of observing processes that have not been explored so far arises, such as meson resonances or VDM-Regge. The observation of photons with transverse momentum less than 1 GeV will be possible in the ALICE 3 experiment planned for the 2030s [7]. In this context, it is vital to not only generate predictions for light-by-light scattering but also to estimate the background.…”