Triggering on Hard Probes in Heavy-Ion Collisions with the CMS Experiment at the LHC Original Research Article

Studies of heavy-ion collisions at the LHC will benefit from an array of qualitatively new probes not readily available at lower collision energies. These include fully formed jets at View the MathML source, Z0ʹs and abundantly produced heavy flavors. For Pb+Pb running at LHC design luminosity, the collision rate in the CMS interaction region will exceed the available bandwidth to store data by several orders of magnitude. Therefore an efficient trigger strategy is needed to select the few percent of the incoming events containing the most interesting signatures. In this report, we will present the heavy-ion trigger strategy developed for the unique two-layer trigger system of the CMS experiment which consists of a “Level-1” trigger based on custom electronics and a High Level Trigger (HLT) implemented using a large cluster of commodity computers.