ALICE experiment


ALICE (A Large Ion Collider Experiment) is one of the four experiments at the Large Hadron Collider (LHC) in Geneva, Switzerland. It is designed to study deeply the heavy ion (Pb-Pb) collisions at the ultra-relativistic energy (up to 5.5 TeV per nucleon in the mass centre) identifying the produced hadrons, electrons, muons and photons.
The ALICE apparatus is quite complex, and from the center to the outer part of the detector we find: Inner Tracking System (ITS) + Muon Forward Tracker (MFT), Time Projection Chamber (TPC) with a radius of 5 m, Transition Radiation Detector (TRD), Time Of Flight (TOF), High Momentum Particle Identification (HMPID), ElectroMagnetic CALorimeter (EMCAL) and the magnet which encloses all.
The Pb-Pb program is accompanied by precision measurements in p-p and p-Pb collisions to provide a quantitative base for comparisons with results from Pb-Pb collisions.
The main goal of the experiment is to study the state of matter called Quark Gluon Plasma (QGP), a state where quarks and gluons are completely deconfined. This state was the one formed within 10-23 seconds after the Big Bang.
The nature of the QGP as an almost-perfect liquid emerged from the experimental investigations at CERN SPS and at BNL RHIC. ALICE has confirmed this basic picture, observing the formation of hot hadronic matter at unprecedented values of temperature, density and volume. These physics results have been achieved by ALICE after only two years of Pb-Pb running and one p-Pb run, demonstrating its excellent capabilities to measure high-energy nuclear collisions at the LHC.
Despite these successes there are several limitations for which the current experimental setup is not yet fully optimized. ALICE is therefore preparing a major upgrade of its apparatus, planned for installation during the Long Shutdown 2 (LS2) of LHC in the years 2019-2020.
The upgraded detector will have greatly improved features in terms of impact parameter resolution, standalone tracking efficiency at low pT, momentum resolution and readout capabilities enhancing ALICE physics capabilities, in particular for high precision measurements of rare probes at low transverse momenta.

Alice experiment Event display

For more information: visit ALICE website