Description:Software for the CMS experiment
Abstract:CMS (Compact Muon Solenoid) is one of the four experiments installed at the Large Hadron Collider (LHC) at CERN in Geneva.<br>
The data taking is foreseen to start in autumn 2008. It will collect events produced in proton-proton collision at 14 TeV in the center of mass, with central attention to Higgs boson and Supersymmetry discovery. A large number of simulated events has been produced in the last years for preliminary studies.<br>
The simulated events are exploited to develop and test the software to be used the data taking. A computing structure organized in tiers has been developed to allow users to access simulated data in a distributed way. After the start-up of the experiment, a few PetaBytes per year, including data and Monte Carlo, are expected to be stored. Major part of data composition is given by background events, which can be skimmed only in off-line analyses. This makes mandatory the adoption of a GRID computing technology. The CMS collaboration has already developed a GRID application to connect the CMS software with the GRID infrastructure. This application, called CRAB (CMS Remote Analysis Builder), is already working and largely used. It has been tested using the GRID technologies during the CMS Computing, Software and Analysis challenges (CSA) in 2006, 2007 and 2008.
An original software package has been written in the context of this application and included in the CMS software framework. It makes use of simulated events to test the trigger of the experiment, with a special attention devoted to triggers for Supersymmetric and Exotic events. The package is now part of the official framework CMSSW, and is used for the validation of the trigger algorithms for every CMSSW release. The CMSSW packages are commonly used through the GRID.