Physics with Jets at the Lhc ∗

The CERN Large Hadron Collider (LHC) is designed to study pp collisions at a center-of-mass energy of 14 TeV and luminosity of 10cms. The GHz collision rate with 20 interactions per 25 ns bunch crossing places unprecedented demands on detector performance. This report will concentrate on jet physics anticipated from the two big general purpose detectors, a toroidal large hadron collider apparatus (ATLAS) and the compact muon solenoid (CMS). Two additional detectors, a large ion collider experiment at CERN (ALICE), and LHC-b, are designed to explore heavy ion and b-quark physics, respectively. Both ATLAS and CMS have charged particle tracking a magnetic field, electromagnetic and hadronic calorimetry, and outer muon chambers. Gone are the days when major collider detectors were designed without magnets! The 7-kiloton ATLAS detector has approximate dimensions 25 m × 46 m featuring huge 0.5-T toroids, while the 14-kiloton CMS is 15 m × 22 m with a 4-T solenoid. The zeroth-order difference between the detectors is that ATLAS has a high fractional magnet cost (40%) providing good stand alone muon measurement, while the lower CMS magnet cost (25%) allows more resources to be spent on a high-resolution silicon tracker and highperformance crystal calorimetry (Fig. 1).