7th international workshop on new Photon-Detectors (PD2025)

Precision timing with the CMS Barrel Timing Layer

4 Dec 2025, 18:07

15m

Auditorium Enzo Biagi (Bologna, Italy)

Talk Timing Applications Plenary Session

Speaker

Martina Malberti (Istituto Nazionale di Fisica Nucleare)

Description

For the High-Luminosity phase of the LHC (HL-LHC), the Compact Muon Solenoid (CMS) experiment is undergoing an upgrade with the addition of the new MIP Timing Detector (MTD), designed to measure the arrival time of charged particles with a precision of 30-60 ps. The time information from the MTD will help handle the expected ~200 concurrent interactions per bunch crossing (pileup) to preserve the present event reconstruction performance. Furthermore, it will introduce new capabilities to the CMS detector by enabling particle identification and expanding the physics reach in searches for long-lived unstable particles. The central part of the MTD, the Barrel Timing Layer (BTL), is made of about 166,000 scintillating LYSO:Ce crystal bars with double-ended SiPM readout. Following its design optimisation and successful performance validation through dedicated test beam campaigns on prototypes, the BTL is now in the construction phase. This contribution will provide an overview of the key design features of the BTL, present recent large-scale system tests and the progress on the BTL assembly, and discuss recent developments in 4D vertex reconstruction and pileup rejection introduced by the MTD.