Experiments at the LHC

The Large Hadron Collider, now under contruction at the European Center for Nuclear Research, represents a unique opportunity for Heavy-Ion Physics. It will provide nuclear collisions at a center-of-mass energy 30 times higher then the present Relativistic Heavy Ion Collider, opening a new era for this field, in which particle production will be dominated by hard processes, and the energy densities will possibly be high enough to treat the generated quark-gluon plasma as an ideal gas. While RHIC is providing a wealth of interesting data, many physicists are working hard to prepare the experiments which will run at the LHC. ALICE, A Large Ion Collider Experiment, the dedicated detector designed to study nucleus-nucleus collisions at the LHC, is developing rapidly: the R&D is essentially complete, and large parts of the main detectors are in production. CMS, Compact Muon Solenoid, an experiments designed for p-p collisions, has defined a Heavy-Ion program, which will expand the LHC nuclear physics reach and provide stimulating competition in the measurement of hard probes. The scientific motivations of the experiments at the LHC are discussed in the review by K. Kajantie [1]. In the following, I will briefly summarize the experimental conditions at the LHC with nuclear beams, describe the main detector components of ALICE and, more briefly, CMS, and shortly discuss the physics program of the two experiments.