Ricerc@Sapienza

During the high-luminosity operation of the large hadron collider (LHC) up to 200 concurrent interactions per-bunch collision are expected, a factor 5 higher than the current LHC conditions. Only one collision contains the rare signatures of interest for discoveries and precision measurements and the contribution of the remaining interactions (pile-up) must be reduced. At such pile-up levels, particle reconstruction and correct assignment to primary interaction vertices present a formidable challenge to the LHC detectors that must be overcome in order to reap that benefit.

An important upgrade of the CMS experiments is planned to fully exploit the leap in luminosity: the goal is to maintain the current excellent detector performance, despite the very challenging operating conditions. In particular CMS has planned to add an hermetic timing detector, to correctly assign charged tracks to their production vertices. Time resolution goal is set to be better than 30 ps per track in order to achieve the needed pile-up rejection factor of ~5-6 per track.

Presently, this new detector is under the research and development phase. The barrel sector will consist of small LYSO crystals read out by silicon photomultipliers: the optimal geometry and the readout electronics is still under discussion.

We propose the test of different configurations and geometries for the barrel detector using a prototype, which will be run at Sapienza with cosmic rays and different radioactive sources and using electrons/pions at beam tests at CERN. In addition, the implementation of a 4D reconstruction which exploits the timing detector information is foreseen by using a detailed simulation of this new detector.