# The upgrade of the CMS $PbWO_{4}$ crystal electromagnetic calorimeter for the HL-LHC and prospects for precision timing resolution.

Da Rold A. per la Collaborazione CMS

Comunicazione
I - Fisica nucleare e subnucleare
Aula 32C-3 - Mercoledì 19 h 09:00 - 13:00
The 61200 $PbWO_{4}$ scintillating crystals, forming the barrel part of the CMS electromagnetic calorimeter, operated successfully in the high radiation environment of the LHC. To cope with the bandwidth and latency requirements of the high luminosity upgrade, a refurbishment of the read-out electronics is foreseen. The upgraded front-end electronics will allow the individual readout of all crystals, exploiting the response of the scintillating crystals to reach a timing resolution of $\approx 30$ps for high energy photons and electrons. We discuss the present timing resolution, benefits of improved precision timing on event reconstruction and studies on the timing properties of the crystals.